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KONSEP DASAR EKOSISTEM
(smno.psdl.ppsub.2013)
Konsep Ekosistem
Suatu EKOSISTEM merupakan lingkungan biologis yang terdiri atas semua organisme hidup
dalam suatu area tertentu, serta komponen abiotik dan komponen fisik dari lingkungan yang
berinteraksi dengan organisme, seperti udara, tanah, air dan radiasi matahari. Ekosistem ini meliputi
semua organisme dalam suatu area tertentu, berinteraksi dengan faktor-faktor abiotik ; merupakan
suatu komunitas biologis dengan lingkungan fisiknya.
“Ekosistem adalah suatu sistem ekologi yang terbentuk oleh hubungan timbal balik tak
terpisahkan antara makhluk hidup dengan lingkungannya. Ekosistem bisa dikatakan juga
suatu tatanan kesatuan secara utuh dan menyeluruh antara segenap unsur lingkungan hidup
yang saling memengaruhi. Ekosistem merupakan penggabungan dari setiap unit biosistem
yang melibatkan interaksi timbal balik antara organisme dan lingkungan fisik sehingga aliran
energi menuju kepada suatu struktur biotik tertentu dan terjadi suatu siklus materi antara
organisme dan anorganisme. Matahari sebagai sumber dari semua energi yang ada. Dalam
ekosistem, organisme dalam komunitas berkembang bersama-sama dengan lingkungan fisik
sebagai suatu sistem. Organisme akan beradaptasi dengan lingkungan fisik, sebaliknya
organisme juga memengaruhi lingkungan fisik untuk keperluan hidup. Pengertian ini
didasarkan pada Hipotesis Gaia, yaitu: "organisme, khususnya mikroorganisme, bersamasama dengan lingkungan fisik menghasilkan suatu sistem kontrol yang menjaga keadaan di
bumi cocok untuk kehidupan". Hal ini mengarah pada kenyataan bahwa kandungan kimia
atmosfer dan bumi sangat terkendali dan sangat berbeda dengan planet lain dalam tata
surya (SUMBER: http://id.wikipedia.org/wiki/Ekosistem).
Ecosystem: Complex of living organisms, their physical environment, and all their
interrelationships in a particular unit of space. An ecosystem's abiotic (nonbiological)
constituents include minerals, climate, soil, water, sunlight, and all other nonliving elements;
its biotic constituents consist of all its living members. Two major forces link these
constituents: the flow of energy and the cycling of nutrients. The fundamental source of
energy in almost all ecosystems is radiant energy from the sun; energy and organic matter
are passed along an ecosystem's food chain. The study of ecosystems became increasingly
sophisticated in the later 20th century; it is now instrumental in assessing and controlling
the environmental effects of agricultural development and industrialization.
(http://www.answers.com/topic/ecosystems-1#ixzz1f2hC3okb)
Definisi Ekosistem
Sistem ekologi dapat didefinisikan sebagai suatu komunitas tumbuhan dan binatang yang
saling berinteraksi beserta lingkungan abiotik atau alamiahnya. Ekosistem-ekosistem dapat
dikelompokkan berdasarkan vegetasi dominannya, topography, iklim atau beberapa criteria lainnya.
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Hutan boreal, misalnya, dicirikan oleh dominasi pohon konifer, padang rumput dicirikan oleh
dominasi rumput, tundra Arktik ditentukan oleh zona iklim yang keras. Di sebagian besar
wilayah dunia, masyarakat manusia merupakan komponen penting dan sering dominan
dalam suatu ekosistem. Ekosistem tidak hanya mencakup wilayah alam (misalnya, hutan,
danau, pesisir laut sistem), tetapi juga sistem binaan manusia (misalnya, ekosistem
perkotaan, agroekosistem, impoundments). Populasi manusia semakin terkonsentrasi di
ekosistem perkotaan, dan diperkirakan bahwa, pada tahun 2010, 50 persen dari populasi
dunia akan tinggal di daerah perkotaan.
Suatu bentang-lahan terdiri atas mozaik ekosistem-ekosistem, termasuk kota-kota, sungai,
danau, system pertanian, dsb. Batas-batas yang tepat di antara ekosistem-ekosistem
tersebut seringkali sulit ditetapkan.
Suatu sistem fungsional yang meliputi komunitas ekologis organisme bersama
dengan lingkungan fisiknya, saling berinteraksi sebagai satu kesatuan. Ekosistem dicirikan
oleh aliran energi melalui jaring-jaring makanan, produksi dan degradasi bahan organik, dan
transformasi serta siklus unsur hara. Produksi molekul organik berfungsi sebagai basis
energi untuk semua aktivitas biologis di dalam ekosistem. Konsumsi tanaman oleh herbivora
(organisme yang mengkonsumsi tanaman hidup atau ganggang) dan detritivores (organisme
yang mengkonsumsi bahan organik mati) berfungsi untuk mentransfer energi yang
tersimpan dalam molekul organik yang diproduksi melalui proses fotosintesis untuk
organisme lain. Proses lain yang berhubungan dengan produksi bahan organik dan aliran
energi adalah siklus unsur hara.
Semua aktivitas biologis dalam ekosistem didukung oleh produksi bahan organik
oleh autotrof (organisme yang dapat menghasilkan molekul organik seperti glukosa dari
karbon dioksida). Lebih dari 99% produksi autotrophic di Bumi melalui proses fotosintesis
oleh tanaman, alga, dan beberapa jenis bakteri. Secara kolektif organisme ini disebut
photoautotrophs (autotrof yang menggunakan energi matahari untuk menghasilkan molekul
organik). Selain fotosintesis, beberapa produksi dilakukan oleh bakteri chemoautotrophic
(autotrof yang menggunakan energi yang tersimpan dalam ikatan kimia dari molekul
anorganik seperti hidrogen sulfida, untuk menghasilkan molekul organik). Molekul-molekul
organik yang dihasilkan oleh autotrophs digunakan untuk mendukung metabolisme
organisme dan reproduksi, serta membangun jaringan baru. Biomasa dalam Jaringan baru
ini dikonsumsi oleh herbivora atau detritivores, yang pada akhirnya dikonsumsi oleh predator
atau detritivores lainnya.
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Skematik wilayah pesisir pantai yang terdiri atas beragam ekosistem
Sumber: http://www.eoearth.org/article/Ecosystems_and_Human_WellBeing:_Volume_1:_Current_State_and_Trends:_Coastal_Systems
Model aliran energy melalui ekosistem.
http://www.answers.com/topic/ecosystems-1#ixzz1f2eXwrp3
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Ekosistem darat (terrestrial ecosystems), yang meliputi 30% permukaan bumi,
menyumbangkan sekitar separuh dari total produksi global bahan organic fotosintetik—sekitar 60 ×
1015 gram karbon per tahun. Lautan, yang meliputi 70% permukaan bumi menghasilkan bahan
organic sekitar 51 × 1015 g C setiap tahun.
Jaring-jaring Makanan
Organisme dapat diklasifikasikan berdasarkan banyaknya transfer energy melalui jaring-jaring
makanan. Produksi bahan organic secara foto-autotrofik mencerminkan transfer energy yang pertama di
dalam suatu ekosistem dan diklasifikasikan denagai PRODUKSI PRIMER. Konsumsi suatu tumbuhan oleh by a
herbivora merupakan transfer energi ke dua , sehingga herbivore menempati tingkat trofik ke dua, juga dikenal
sebagai PRODUKSI SEKUNDER. Organiske konsumen yang merupakan transfer ke satu, dua atau tiga dari fotoautotrof dikelompokkan sebagai konsumen primer, sekunder, dan tersier. Bergerak melalui suatu jarring-jaring
makanan, energy hilang selama proses transfer sebagai panas, sebagaimana dijelaskan dengan Hukum
Termodinamika ke dua. Oleh karena itu, jumlah total transfer energy jarang yang melebihi empat atau lima;
dengan adanya kehilangan energy selama setiap proses transfer, maka sedikit sekali energy yang tersedia
untuk mendukung organism yang berada pada tingkat tertinggi dari suatu jaring-jaring makanan.
“Energy flow drives the ecosystem, determining limits of the food supply and the
production of all biological resources. Light energy from the sun is captured by green
plants and converted to chemical energy. Energy is stored in plants as carbohydrates and
used by the plant to support all functions such as vegetative growth, fruit maturation and
respiration. Other organisms use and convert this chemical energy to various forms
through food chains. A food chain is a succession of organisms in a community that
constitutes a feeding sequence in which food energy is transferred from one organism to
the next as each consumes a lower number and in turn is preyed upon by a higher number.
At the bottom of the chain is a photosynthesizing plant, usually followed by an herbivore,
a successions of carnivores, and finally decomposers. At each step, some of the chemical
energy is assimilated and used by the organism and the rest is released in respiration and
waste products”.
Jaring-jaring makanan (Food web) merupakan rantai-rantai makanan yang saling berkaitan
secara “rumit” dalam suatu komunitas. Struktur trofik (Trophic structure) merupakan serangkaian
keterkaitan dalam suatu jaring-jaring makanan yang mendeskripsikan transfer energy dari suatu
tingkat nutritional ke tingkat berikutnya. Sasaran produksi tanaman adalah memaksimumkan energy
ekosistem ke dalam hasil-panen; penggunaan energy tanaman oleh hama tidak diperlukan karena
hal ini berarti mengambil energy dari produksi tanaman.
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Dalam suatu siklus biogeokimia, unsure-unsur hara anorganik yang diperlukan untuk pertumbuhan dan perkembangan organism bersirkulasi dari komponen
abiotik ke komponen biotic dan kembali lagi ke komponen abiotik dari ekosistem (Source Flint, M.L and P. Gouveia, 2001)
Sumber: http://www.knowledgebank.irri.org/ipm/index.php/ecosystem-ecology….. diunduh 29/6/2011
Diagram jaring-jaring makanan dalam alfalfa. Setiap tanda panah mencerminkan transfer makanan, atau energy dari satu organism ke organism lainnya.
Jaring-jaring menjadi lebih kompleks kalau semakin banyak spesies yang dimasukkan ke dalam system. (Flint, M.L. and P. Gouveia. 2001).
Sumber: http://www.knowledgebank.irri.org/ipm/index.php/ecosystem-ecology….. diunduh 29/6/2011
Organisme hidup membentuk jaring-jaring makanan
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Organisme yang hidup di dalam suatu agroekosistem merupakan komponen biotik.
Organisme dapat dianalisis sebagai jaring makanan yang mencerminkan transfer material
dan energi dari satu kelompok organisme kepada kelompok organism yang lain . Untuk
analisis jaring makanan , organisme dikelompokkan menurut fungsinya dalam aliran energi
dan hara, dan bukan klasifikasi menurut genus dan spesiesnya. Semua tanaman dalam
suatu agro-ekosistem membentuk produsen primer dan menjadi dasar dari jarring-jaring
makanan. Tanaman menangkap energi matahari melalui daun dan dikombinasikan dengan
air dan hara dari tanah dan karbon dioksida dari udara menghasilkan bahan biomasa
tanaman . Organisme tingkat berikutnya adalah herbivora yang hidup dari hara dan energi
yang dihasilkan oleh tanaman atau produsen primer lainnya. Banyak jenis organisme dapat
bertindak sebagai herbivora, seperti burung , serangga , nematoda , jamur , bakteri dan
virus. Selanjutnya, energi dan hara dalam herbivora dieksploitasi untuk pertumbuhan dan
reproduksi oleh kelompok lain dari organisme yang disebut konsumen sekunder. Hewan
yang hidup dari energi dan hara dalam substansi konsumen sekunder disebut konsumen
tersier . Banyak jenis organisme juga dapat bersifat sebagai konsumen primer , konsumen
sekunder dan tersier .
Sumber: http://www.knowledgebank.irri.org/ipm/index.php/ecosystem-ecology….. diunduh 29/6/2011
Sumber: http://platforms.inibap.org/agro/concepts.html ….. diunduh 29/6/2011
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Jaring makanan dalam tanah memiliki banyak organisme yang memangsa biomasa
tumbuhan hidup dan mati. Dengan demikian, banyak organisme memperoleh energi
untuk tumbuh dan berkembang biak dan akhirnya hara yang diikat dalam biomasa
tumbuhan dan hewan dapat tersedia kembali untuk pertumbuhan tanaman.
Sumber: http://platforms.inibap.org/agro/concepts.html ….. diunduh 29/6/2011
Burung merupakan salah satu organism (fauna) dalam jaring-jaring makanan ekosistem
pantai mempunyai peran yang sangat penting.
Sumber: http://www.touregypt.net/parks/linked_coastal_ecosystems.htm
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Siklus Biogeokimia
Berbeda dengan energi, yang hilang dari ekosistem sebagai panas, unsur hara (atau
nutrisi) yang membentuk molekul dalam organisme tidak berubah dan dapat berulang-ulang
ber-siklus di antara organisme dan lingkungan hidupnya. Sekitar 40 unsur menyusun tubuh
organisme, dimana karbon, oksigen, hidrogen, nitrogen, dan fosfor yang paling banyak. Jika
salah satu dari unsure tersebut dalam lingkungan tumbuh suplainya kurang, pertumbuhan
organisme dapat terhambat, meskipun tersedia cukup banyak energi. Secara khusus,
nitrogen dan fosfor adalah elemen yang paling sering membatasi pertumbuhan organisme.
Keterbatasan ini ditandai oleh meluasnya penggunaan pupuk, yang diterapkan pada bidang
pertanian untuk mengatasi kurangnya ketersediaan hara.
The movement of energy from one level of the food web to the next. The proportion of
energy at one level of the food web that makes it to the next level is called ecological
efficiency - this is usually less than 10%. In an agroecosystem, we also care about how well
the energy consumed by organisms, usually either the crop plants (the producers, with
energy from the sun) or livestock (herbivores, with energy from feed or pasture), is
converted into body tissue - this is conversion efficiency.
Sumber: http://www.acad.carleton.edu/curricular/BIOL/classes/bio160/ClassResources/Case_Studies/Case3_Energy/Case3_Directions.htm ….. diunduh
29/6/2011
Siklus karbon terjadi di antara atmosfer dan ekosistem darat dan laut. Siklus ini
terjadi ada kaitannya dnegan produksi primer dan dekomposisi bahan organik.
Tingkat produksi primer dan dekomposisi bahan organik, selanjutna dikendalikan
oleh pasokan nitrogen, fosfor, dan zat besi. Pembakaran bahan bakar fosil
merupakan perubahan terbaru siklus global yang melepaskan karbon yang telah
lama terkubur dalam kerak bumi ke dalam atmosfer. Karbon dioksida di atmosfer
menangkap panas pada permukaan bumi dan merupakan faktor utama yang
mengatur iklim. Perubahan siklus karbon global ini mengakibatkan dampak pada
iklim, isu-isu ini merupakan masalah besar yang sedang diselidiki oleh ahli ekologi
ekosistem.
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Siklus Karbon
Organic chemicals are made from carbon more than any other atom, so the Carbon Cycle is a
very important one. Carbon between the biological to the physical environment as it moves
through the carbon cycle.
Earth's atmosphere contains 0.035% carbon dioxide, CO2, and the biological environment
depends upon plants to pull carbon into sugars, proteins, and fats. Using photosynthesis,
plants use sunlight to bind carbon to glucose, releasing oxygen (O2)in the process. Through
other metabolic processes, plants may convert glucose to other sugars, proteins, or fats.
Animals obtain their carbon by eating and digesting plants, so carbon moves through the
biotic environment through the trophic system. Herbivore eat plants, but are themselves
eaten by carnivores.
Karbon kembali ke lingkungan fisik melalui beberapa cara. Tanaman dan hewan
melakukan respirasi, sehingga mereka melepaskan CO2 selama respirasinya.
Tumbuhan dapat mengkonsumsi lebih banyak CO2 melalui fotosintesis daripada
yang dapat dihasilkannya melalui respirasi. Jalur lain kembalinya CO2 ke lingkungan
fisik terjadi melalui kematian tanaman dan hewan. Kalau organisme mati, bakteri
dekomposer mengkonsumsi biomasa. Dalam proses dekomposisinya, sejumlah
karbon dilepaskan kembali ke lingkungan fisik dengan cara fosilisasi. Sebagian
karbon tetap tinggal dalam lingkungan biologis kalau organisme lain memangsa
decomposer tersebut. Namun sejauh ini, sebagian besar karbon kembali ke
lingkungan fisik melalui proses respirasi CO2.
Sumber: http://www.starsandseas.com/SAS%20Ecology/SAS%20chemcycles/cycle_carbon.htm ..... diunduh 29/6/2011
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Siklus Nitrogen
Protein, asam nukleat , dan bahan kimia organik lainnya mengandung nitrogen ,
sehingga nitrogen adalah unsur yang sangat penting dalam organisme biologis .
Nitrogen menyusun 79% dari atmosfer bumi , namun sebagian besar organisme
tidak dapat menggunakan gas nitrogen (N2). N2 memasuki sistem trofik melalui
proses fiksasi nitrogen . Bakteri yang ditemukan pada akar beberapa tanaman
legume dapat memfiksasi N2 menjadi molekul organik, membentuk protein.
Demikian juga, hewan mendapatkan nitrogen dengan jalan memakan biomasa
tanaman. Tetapi setelah titik ini , siklus nitrogen akan jauh lebih rumit daripada siklus
karbon. Hewan melepaskan nitrogen dalam urine-nya . Ikan melepaskan NH3 , tetapi
kalau konsnetrasi NH3 pekat, bersifat racun bagi organisme hidup . Jadi organisme
harus mengencerkan NH3 dengan banyak air . Kehidupan air , ikan tidak
menghadapi masalah dengan persyaratan ini, tetapi hewan darat memiliki masalah
serius. Mereka mengkonversi NH3 menjadi urine, atau senyawa kimia lainnya yang
tidak beracun seperti NH3 . Proses pelepasan NH3 disebut ammonification . Karena
NH3 bersifat racun , sebagian besar NH3 yang dilepaskan tidak tersentuh . Tetapi
bakteri tanah memiliki kemampuan untuk mengasimilasi NH3 menjadi protein .
Bakteri ini efektif memakan NH3 , dan membuat protein darinya. Proses ini disebut
asimilasi .
Some soil bacteria does not convert NH3 into proteins, but they make nitrate NO3- instead.
This process is called nitrification. Some plants can use NO3-, consuming nitrate and making
proteins. Some soil bacteria, however, takes NO3-, and converts it into N2, returning
nitrogen gas back into the atmosphere. This last process is called denitrification, because it
breaks nitrate apart.
Sumber: http://www.starsandseas.com/SAS%20Ecology/SAS%20chemcycles/cycle_carbon.htm .....
diunduh 29/6/2011
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Siklus Phosphorus
Fosfor adalah kunci untuk system energi dalam organisme, fosfor yang
menggerakkan energi dari ATP ke molekul lain , mengendalikan reaksi enzimatik,
atau transportasi seluler. Fosfor juga merupakan perekat yang memegang DNA
bersama-sama , mengikat gula deoksiribosa bersama-sama , membentuk tulang
punggung dari molekul DNA. Fosfor melakukan fugnsi yang sama di dalam RNA .
Faktor kunci untuk memasukkan fosfor ke dalam sistem tropik adalah tanaman.
Tanaman menyerap fosfor dari air dan tanah ke dalam tubuhnya, mensintesisnya
menjadi molekul P-organik . Setelah diambil oleh tanaman, fosfor yang tersedia bagi
hewan yang mengkonsumsi biomasa tanaman. Ketika tumbuhan dan hewan mati,
bakteri mendekomposisi biomasa, melepaskan sejunmlah fosfor anorganik kembali
ke tanah. Di dalam tanah , fosfor dapat bergerak sejauh 100 - 1.000 mil dari tempat
dimana P dilepaskan, melalui aliran air dan sungai. Dengan demikian siklus air
memainkan peran kunci dalam pergerakan fosfor dalam ekosistem . Dalam beberapa
kasus , fosfor diangkut memasuki danau , dan menetap di dalam sedimen di bagian
dasar danau. Di dasar danau ini, fosfor dapat berubah menjadi batuan sedimen ,
batu kapur , yang akan dirilis jutaan tahun kemudian . Batuan sedimen berfungsai
sebagai cadangan, melestarikan banyak fosfor untuk digunakan di masa depan .
Sumber: http://www.starsandseas.com/SAS%20Ecology/SAS%20chemcycles/cycle_carbon.htm ..... diunduh
29/6/2011
Siklus hara dalam suatu agroekosistem melibatkan tanaman, ikan dan ternak. Salah satu
jalur utama aliran hara adalah jalur tanaman-ternak-tanah. KOlam ikan, jalur utamanya adalah
tanaman dan ternak. Dalam beberapa kasus dalam system pertanian tradisional di Asia, limbah
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manusia dan rumahtangga menjadi input penting bagi tanaman dan kolam ikan, sedangkan limbah
dapur penting bagi ternak dan kolam ikan.
Sumber: Edwards (1993) (http://www.fao.org/docrep/006/y5098e/y5098e05.htm ..... diunduh 2/7/2011)
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Aliran hara di antara komponen dalam agroekosistem dan antara agroekosistem dengan system
eksternalnya adalah sebagai berikut.
Sumber: Le and Rambo (1993) (http://www.fao.org/docrep/006/y5098e/y5098e05.htm ..... diunduh 2/7/2011)
Fotosintesis
Organisme dan fungsi suatu sel hidup bergantung pada persediaan energi yang tak hentihentinya, sumber energi ini tersimpan dalam molekul-molekul organik seperti karbohidrat.
Organisme heterotrofik seperti ragi dan kita sendiri, hidup dan tumbuh dengan memasukkan
molekul-molekul organik ke dalam sel-selnya. Untuk tujuan praktis, satu-satunya sumber molekul
bahan bakar yang menjadi tempat bergantung seluruh kehidupan ialah fotosintesis. Fotosintesis
menyediakan makanan bagi hampir seluruh kehidupan di dunia baik secara langsung atau tidak
langsung. Organisme memperoleh senyawa organik yang digunakan untuk dan rangka karbon
dengan satu atau dua cara utama: nutrisi autotrofik atau heterotrofik. Autotro dapat diartikan
bahwa dapat menyediakan makanan bagi diri sendiri hanya dalam pengertian bahwa autotrof dapat
mempertahankan dirinya sendiri tanpa memakan dan menguraikan organisme lain. Autotrof
membuat molekul organik mereka sendiri dari bahan mentah anorganik yang diperoleh dari
lingkuannya. Oleh karena alasan inilah, para ahli biologi menyebut autotrof sebagai produsen
biosfer.
Organisme heterotrof memperoleh materi organik melalui cara pemenuhan nutrisi kedua.
Ketidakmampuan dalam membuat makanan mereka sendiri, menyebabkan hererotrof ini
hidup tergantung pada senyawa yang dihasilkan oleh organisme lain; heteritrif merupakan
komponen biosfer. Sebagian autotrof mengkonsumsi sisa-sisa organisme mati, menguraikan
dan memekan sampah seperti bangkai, tinja dan daun-daun yang gugur. Heterotrof ini
dikenak sebagai pengurai. Sebagian besar fungi dan banyak jenis bakteri memperoleh
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makana dengan cara seperti ini. Hampir seluruh heterotrof, termrasuk manusia, benar-benar
tergantung pada fotoautotrof untuk mrndapatkan makanan dan juga untuk mendapatkan
oksigen, yang merupakan produk samping fotosintesis.
Jalur Fotosintesis
Dengan keberadaan cahaya, bagian-bagian tumbuhan yang berwarna hijau menghasilkan
bahan organik dan oksigen dari karbon dioksida dan air. Dengan menggunakan rumus molekul,
persamaan kimia fotosintesis adalah:
6CO2 + 12 H2O + energi cahaya -----> C6H12O6 + 6O2 + 6H2O
Karbohidrat C6H12O6 ialah glukosa. Air muncul pada kedua sisi persamaan itu karena 12
molekul dikonsumsi dan 6 molekul terbentuk lagi selama fotosintesis. Persamaan itu dapat
disederhanakan dengan memperlihatkan selisih konsumsi air:
6CO2 + 6H2O + energi cahaya ----> C6H12O6 + 6O2
Dalam bakteri berfotosintesis, sebagai pengganti H2O dipakai zat pereduksi yang lebih kuat
seperti H2, H2S dan H2R (R adalah gugus organik). Persamaan reaksinya adalah:
2CO2 + 2H2R -----> 2C2O + O2 +2R
Bakteri menggunakan H2R dan menggunakan hidrogen untuk membuat gula. Dari reaksi
kimia tersebut dapat dikatakan bahwa semua organisme fotosintetik membutuhkan sumber
hidrogen, tetapi sumber itu bermacam-macam.
Tempat Berlangsungnya Proses Fotosintesis
Di dalam tumbuhan, proses fotosintesis pada umumnya berlangsung dalam organel khusus
yang disebut plastid. Plastid mengandung senyawa, yaitu klorofil. Semua bagian yang berwarna hijau
pada tumbuhan, termasuk batang hijau dan buah yang belum matang, memiliki kloroplas, tetapi
daun merupakan tempat utama berlangsungnya fotosintesis pada sebagian besar tumbuhan.
Terdapat ± setengah juta kloroplas tiap milimeter persegi permukaan daun. Warna daun berasal dari
klorofil, pigmen warna hijau yang terdapat dalam kloroplas. Energi cahaya yang diserap klorofil inilah
yang menggunakan sintesis molekul makanan dalam kloroplas.
Sebagian besar spesies tumbuhan, terpacu pertumbuhan dan perkecambahan dalam
keadaan terang. Namun biji juga dapat terhambat perkecambahanyya oleh cahaya. Panjang
gelombang merah jauh dari sinar matahari hampir selalu merupakan panjang gelombang yang paling
menghambat. Cahaya biru juga kadang menghambat. Biji yang membutuhkan cahaya untuk
berkecambah disebut fotodorman. Biji yang biasanya berkecambah dalam gelap akan terhambat
oleh cahaya. Biji yang biasa berkecambah dalam gelap akan mengalami dormansi atau fase istirahat
saat terkena cahaya dalam tingkat intensitas tertentu.
Cahaya tampak sebagai sumber energi yang digunakan tumbuhan untuk fotosintesis
merupakan bagian spektrum energi radiasi. Reaksi cahaya dalam fotosintesis merupakan bagian
akibat langsung penyerapan foton oleh molekul pigmen seperti klorofil. Menurut Michael (1994),
tidak seluruh foton mempunyai tingkat energi yang sesuai untuk aktivasi pigmen daun. Di atas 760
nm foton tidak memiliki cukup energi dan di bawah 390 nm foton memiliki terlalu banyak energi, hal
15
ini dapat menyebabkan ionisasi dan kerusakan pigmen. Hanya foton dengan panjang gelombang
antara 390 dan 760 nm memiliki tingkat energi yang cocok untuk fotosintesis. Aktivasi pigmen
merupakan akibat langsung dari interaksi antara foton dengan pigmen, maka pengukuran cahaya
yang digunakan dalam fotosintesis seringkali dilakukan berdasarkan densitas aliran foton, dan bukan
berdasarkan energi. Densitas aliran foton merupakan jumlah foton yang menumbuk suatu luas
permukaan tertentu per satuan waktu. Panjang gelombang antara 400 dan 700 nm mempunyai
efisiensi tinggi dalam fotosintesis, maka pengukuran cahaya untuk fotosintesis biasanya didasarkan
pada densitas aliran foton dalam panjang gelombang 400 dan 700 nm.
Sumber: http://ecology07.blogspot.com/2011_03_01_archive.html …. Diunduh 29/6/2011
16
Kesehatan Ekosistem
It is important to recognize the inherent difficulties in defining "health," whether at the level
of the individual, population, or ecosystem. The concept of health is somewhat of an enigma, being
easier to define in its absence (sickness) than in its presence. Perhaps partially for that reason,
ecologists have resisted applying the notion of "health" to ecosystems. Yet, ecosystems can become
dysfunctional, particularly under chronic stress from human activity. For example, the discharge of
nutrients from sewage, industrial waste, or agricultural runoff into lakes or rivers affects the normal
functioning of the ecosystem, and can result in severe impairment. Excessive nutrient inputs from
human activity was one of the major factors that severely compromised the health of the lower
Laurentian Great Lakes (Lake Erie and Lake Ontario) and regions of the upper Great Lakes (Lake
Michigan). Unfortunately, degraded ecosystems are becoming more the rule than the exception.
The study of the features of degraded systems, and comparisons with systems that have not
been altered by human activity, makes it possible to identify the characteristics of healthy
ecosystems. Healthy ecosystems may be characterized not only by the absence of signs of pathology,
but also by signs of health, including measures of vigor (productivity), organization, and resilience.
Vigor can be assessed in terms of the metabolism (activity and productivity) of the system.
Ecosystems differ greatly in their normal ranges of productivity. Estuaries are far more productive
than open oceans, and marshes have higher productivity than deserts. Health is not evaluated by
applying one standard to all systems. Organization can be assessed by the structure of the biotic
community that forms an ecosystem and by the nature of the interactions between the species
(both plants and animals). Invariably, healthy ecosystems have more diversity of biota than
ecologically compromised systems. Resilience is the capacity of an ecosystem to maintain its
structure and functions in the face of natural disturbances. Systems with a history of chronic stress
are less likely to recover from normal perturbations such as drought than those systems that have
been relatively less stressed.
“Healthy ecosystems can also be characterized in economic, social, and human health terms.
Healthy ecosystems support a certain level of economic activity. This is not to say that the
ecosystem is necessarily self-sufficient, but rather that it supports economic productivity to
enable the human community to meet reasonable needs. Inevitably, ecosystem degradation
impinges on the long-term sustainability of the human economy that is associated with it,
although in the short-term this may not be evident, as natural capital (e.g., soils, renewable
resources) may be overexploited and temporarily enhance economic returns. Similarly, with
respect to social well-being, healthy ecosystems provide a basis for and encourage community
integration. Historically, for example, native Hawaiian groups managed their ecosystem through
a well-developed social cohesiveness that provided a high degree of cooperation in fishing and
farming activity”.
17
Kesehatan Agro-ecosystem
Salah satu hipotesis dasar dalam suatu proposal penelitian adalah bahwa
“paradigma kesehatan agro-ekosistem” akan menyediakan kerangka kerja
konseptual yang bagus daripada “paradigma keberlanjutan-pertanian”, yang ' tidak
mengandung banyak fakta empiris karena kurangnya definisi yang komprehensif dan
metodologi analitis' (ILRI 1998). Kedua paradigm tersbeut memang dapat dibedakan,
tetapi untuk tujuan praktis biasanya keduanya dianggap sama, pada dasarnya identik
(perbandingan ini dikembangkan secara lebih rinci dalam Smit dan Smithers (1994).
Begitu istilah 'agro digabungkan dnegan “ekosistem”
maka secara eksplisit
komponen manusia dilibatkan, sehingga agro-ekosistem pada dasarnya setara
dengan definisi yang luas dari “pertanian”, yang mencakup komponen ekologi dan
manusia.
“Sustainable agriculture” telah didefinisikan dengan berbagai cara dan sudut pandang (Smit
and Brklacich 1989; Cai and Smit 1994; Smit and Smithers 1994), tetapi kebanyakan melingkupi sifatsifat esensial yang sama. Misalnya dua definisi berikut ini:
Agri-food systems that are economically viable, meet society's need for safe and nutritious
foods, while conserving natural resources and the quality of the environment for future
generations (SCC 1992),
Agricultural system that can indefinitely meet demands for food and fibre at socially
acceptable economic and environmental costs (Crosson 1992).
Dalam kedua hal tersebut di atas, pertanian berkelanjutan didefinisikan dengan
memperhatikan:
 Kebutuhan atau permintaan social atas pangan, termasuk gizi, dan mencerminkan
kesehatan manusia
 Kelayakan ekonomis, mengacu kepada pemeliharaan system produksi
 Kualitas lingkungan, yang diarahkan pada kondisi sumberdaya biofisik.
Definisi “keberlanjutan” juga memperhatikan sifat-sifat ini atas waktu ('generasi mendatang”
atau 'indefinite'). Definisi kesehatan agro-ecosystem melingkupi sifat-sifat esensial yang sama, yaitu:
1. Kesejahteraan manusia
2. Keragaan ekonomis, dan
3. Kondisi ekologis.
Pada kenyataannya, esensi dari perspektif kesehatan agroekosistem (agro-ecosystem health,
AESH) adalah bahwa ia mencerminkan eksistensi dan interrelationships di antara beberapa domain
system pertanian (economi, manusia dan ekologi), dan bahwa kesehatan system secara keseluruhan
merupakan fungsi dari kondisi dan interdependensi di antara komponen-komponen ini.
A simple conceptualisation of agro-ecosystem health indicates three main dimensions,
which interact (hence overlapping sets), which manifest at different scales (hence the different sizes
of sets), and which can be employed in numerous applications, including a) using indicators to
compare systems or document changes in AESH, b) identifying and specifying relationships among
18
dimensions to understand dynamics and determinants of AESH, and c) assessing responses in AESH
to stresses, both those associated with external environments (such as climatic variations or macroeconomic conditions) and those reflecting interventions or policies.
Kesehatan Agro-ecosystem: Suatu teladan representasi diagramatik.
Landasan konseptual dari dua paradigm ini, AESH dan agricultural sustainability (AS), pada
hakekatnya sinonim. Keduanya bersifat evaluative dari keseluruhan kondisi lingkungan pedesaan,
ekonomi, dan manusia. Sehingga sasarannya juga meliputi komponen ini:

Peningkatan ketahanan pangan

Pengentasan kemiskinan

Melestarikan kualitas lingkungan yang baik.
In other respects as well, AESH and AS are very similar. Both are applicable at different
spatial and temporal scales. For both, considerable effort has been expended in developing
indicators, and similar kinds of indicators (often very long lists) have been proposed.
Indicators can take a wide variety of forms, including state and functional indicators,
diagnostic and early warning indicators. There are also many examples of particular
empirical studies employing indicators, especially of sustainable agriculture . However,
neither of these frameworks can supply a single, comprehensive measurable indicator which
can adequately capture the scope of these systems. Nor do either of them provide a specific
set of analytical steps to document change, assess responses, or evaluate interventions in
these systems. The noteworthy contribution of the agro-ecosystem health concept is a
metaphor, providing a broad framework which facilitates the consideration of multiple
dimensions and the interactions among them.
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Indikator kesehatan agro-ecosystem
What is the route by which a metaphor or concept can be applied to something so that
researchers or practitioners can use in the field? For example, there is the interest in indicators, or
measurable properties which indicate the health of an agro-ecosystem. For indicators, which
represent only one element of any analysis, three distinct approaches have been tried.
Holistik
This approach, of which several versions have been proposed, aims to define a set of very
generic 'criteria', essentially from first principles, which will be applicable to all dimensions. Thus, we
get such 'holistic indicators' as integrity, efficiency, resilience, effectiveness, response capability,
balance, richness, transformation ability, self-regulatory capacity, flexibility, stability, and so on. A
particular appeal of this approach is the expectation that the selected criteria will lead to
measurable equivalent indicators on each of the dimensions.
A conceptual framework for agro-ecosystem health.
Sumber: http://www.ilri.org/InfoServ/Webpub/fulldocs/Aesh/Concepts.htm ..... diunduh 29/6/2011
Terintegrasi = Disaggregated
In this approach, the indicators of the various dimensions of agro-ecosystem health are
supplied by scientists and practitioners in each of the disciplines involved. Indicators developed via
this route tend to reflect the variables which are conventionally analysed in the various disciplines.
Thus, economists provide indicators such as gross margins, benefit /cost ratios, or net income.
Sociologists will list measures of household and community structure, power relations, equity,
gender roles, and so on. From the human health and nutrition fields come indicators of morbidity,
longevity, other physiological features and measures of nutritional status or functionality. From the
geophysical and biological sciences come equally long lists of ecosystem variables which have been
of theoretical interest or have been used before. This approach certainly generates an ample
smorgasbord of indicators. The weaknesses of this approach are that the lists are impractically long,
20
there are no established principles for selecting from among the many possibilities (they may all be
'scientifically valid'), and they often are not readily understood by the people in the agroecosystems.
Berbasis Komunitas = Community-based
The essence of this approach (also called stakeholder-derived) is that the indicators are
identified with the active participation of the people who live in the agro-ecosystem. A variety of
methods are available for this kind of participatory approach, in which the researchers necessarily
play at least a facilitatory role, but where the indicators are certainly meaningful to local people as
well as to the analysts. These include a practical and efficient way of selecting key indicators,
allowing researchers to learn about communities' priorities and alternative measurements
(sometimes supplied directly by residents), and promotion of people's involvement in (and
'ownership of') both analysis of agro-ecosystems and any management initiatives to improve their
health.
Bagaimana Ekosistem Sehat menjadi Patologis
Stress from human activity is a major factor in transforming healthy ecosystems to sick
ecosystems. Chronic stress from human activity differs from natural disturbances. Natural
disturbances (fires, floods, periodic insect infestations) are part of the dynamics of most ecosystems.
These processes help to "reset" ecosystems by recycling nutrients and clearing space for
recolonization by biota that may be better adapted to changing environments. Thus, natural
perturbations help keep ecosystems healthy. In contrast, chronic and acute stress on ecosystems
resulting from human activity (e.g., construction of large dams, release of nutrients and toxic
substances into the air, water, and land) generally results in long-term ecological dysfunction.
Lima sumber utama cekaman (stress) antropogenik (akibat dari kegiatan manusia) terhadap
ekosistem, yaitu: rekayasa struktur fisik, panen berlebihan, limbah residual, masuknya
spesies eksotik, dan perubahan global.
Rekayasa Struktur Fisik
Aktivitas-aktivitas seperti drainage rawa-rawa, pengerukan dasar danau, pembendungan
sungai, dan pembangunan jalan raya, berarti proses fragmentasi bentang lahan dan
mengubah serta merusak habitat-habitat kritis. Aktivitas-aktivitas ini juga mengganggu siklus
hara dan menyebabkan hilangnya biodiversitas.
Panen berlebihan
Overexploitation is commonplace when it comes to harvesting of wildlife, fisheries, and
forests. Over long periods of time, stocks of preferred species are reduced. For example, the
giant redwoods that once thrived along the California coast now exist only in remnant
patches because of overharvesting. When dominant species like the giant redwoods
(arguably the world's tallest tree—one specimen was recorded at 110 meters tall with a
circumference of 13.4 meters) are lost, the entire ecosystem becomes transformed.
Overharvesting often results in reduced biodiversity of endemic species, while facilitating
the invasion of opportunistic species.
21
Limbah / Residu.
Discharges from municipal, industrial, and agricultural sources into the air, water, and land
have severely compromised many of the earth's ecosystems. The effects are particularly
apparent in aquatic ecosystems. In some lakes that lack a natural buffering capacity, acid
precipitation has eliminated most of the fish and other organisms. While the visual effect
appears beneficial (water clarity goes up) the impact on ecosystem health is devastating.
Systems that once contained a variety of organisms and were highly productive (biologically)
become devoid of most lifeforms except for a few acid-tolerant bacteria and sedimentdwelling organisms.
Introduksi Spesies Eksotik
The spread of exotics has become a problem in almost every ecosystem of the world.
Transporting species from their native habitat to entirely new ecosystems can wreck havoc,
as the new environments are often without natural checks and balances for the new species.
In the Great Lakes Basin, the accidental introduction of two small pelagic fishes, the alewife
and the rainbow smelt, combined with the simultaneous overharvesting of natural
predators, such as the lake trout, led to a significant decline in native fish species.
The introduction of the sea lamprey, an eel-like predacious fish that attacks larger fish, into
Lake Erie and the upper Great Lakes further destabilized the native fish community. The sea
lamprey contributed to the demise of the deepwater benthic fish community by preying on
lake trout, whitefish, and burbot. This contributed to a shift in the fish community from one
that had been dominated by large benthics to one dominated by small pelagics (fish found in
the upper layers of the lake profile). This shift from bottom-dwelling fish (benthic) to
surface-dwelling fish (pelagic) has now been partially reversed by yet another accidental
introduction of an exotic: the zebra mussel. As the zebra mussel is a highly efficient filter of
both phtyoplankton and zooplankton, its presence has reduced the available food in the
surface waters for pelagic fish. However, while the benthic fish community has gained back
its dominance, the preferred benthic fish species have not yet recovered owing to the
degree of initial degradation. Overall, the increasing dominance by exotics not only altered
the ecology, but also reduced significantly the commercial value of the fisheries.
Perubahan Global
Rapid climate change (or climate warming) is an emerging potential global stress on all of
the earth's ecosystems. In evolutionary time, there have of course been large fluctuations in
climate. However, for the most part these fluctuations have occurred gradually over long
periods of time. Rapid climate change is an entirely different matter. By altering both
averages and extremes in precipitation, temperature, and storm events, and by destabilizing
the El Niño Southern Oscillation (ENSO), which controls weather patterns over much of the
southern Pacific region, many ecosystem processes can become significantly altered.
Excessive periods of drought or unusually heavy rains and flooding will exceed the tolerance
for many species, thus changing the biotic composition. Flooding and unusually high winds
contribute to soil erosion, and at the same time add to nutrient load in rivers and coastal
waters.
22
These anthropogenic stresses have compromised ecosystem function in most regions of the
world, resulting in ecosystem distress syndrome (EDS). EDS is characterized by a group of
signs, including abnormalities in nutrient cycling, productivity, species diversity and richness,
biotic structure, disease prevalence, soil fertility, and so on. The consequences of these
changes for human health are not inconsiderable. Impoverished biotic communities are
natural harbors for pathogens that affect humans and other species.
Kesehatan Ekosistem dan Kesehatan Manusia
An important aspect of ecosystem degradation is the associated increased risk to human
health. Traditionally, the concern has been with contaminants, particularly industrial chemicals that
can have adverse impacts on human development, neurological functions, reproductive functions,
and that appear to be causative agents in a variety of carcinomas. In addition to these serious
environmental concerns (where the remedies are often technological, including engineering
solutions to reduce the release of contaminants), there are a large number of other risks to human
health stemming from ecological imbalance.
Ecosystem distress syndrome results in the loss of valued ecosystem services, including flood
control, water quality, air quality, fish and wildlife diversity, and recreation. One of the major signs of
EDS is increased disease incidence, both in humans and other species. Human population health
should thus be viewed within an ecological context as an expression of the integrity and health of
the life-supporting capacity of the environment. Ecological imbalances triggered by global climate
change and other causes are responsible for increased human health risks.
Hubungan keterkaitan antara jasa-jasa ekosistem, aspek kesejahteraan manusia dan Kesehatan
Manusia
23
Sumber: http://www.mindfully.org/Heritage/2005/Ecosystem-Degradation-Threats9dec05.htm ….. diunduh 1/7/2011
Tekanan-tekanan terhadap ekosistem dapat mengakibatkan gangguan yang tidak terduga pada
aspek kesehatan masa mendatang. Beberapa masalah yang sangat serius adalah
(Sumber: http://www.who.int/mediacentre/news/releases/2005/pr67/en/index.html:)
 Gizi dan Nutrisi: Degradasi ekosistem perikanan dan ekosistem pertanian merupakan factorfaktor penyebab mal-nutrisi yang dialami 800 juta manusia di seluruh dunia. Ada banyak
penduduk lainnya yang mengalami defisiensi kronis mikro-nutrient.
 Air minum yang aman: Water-associated infectious diseases claim 3.2 million lives,
approximately 6% of all deaths globally. Over one billion people lack access to safe water
supplies, while 2.6 billion lack adequate sanitation, and related problems of water scarcity
are increasing, partly due to ecosystem depletion and contamination.
 Ketergantungan pada bahan bakar padat: Sekitar 3% dari beban gangguan penyakit global
disebabkan oleh pencemaran udara “indoor”, penyebab utama penyakit pernafasan. Banyak
penduduk dunia menggunakan bahan bakar padat untuk memasak makanan dan
menghangatkan ruangan, merupakan penyebab utama penggundulan hutan.
Perubahan Iklim dan Vektor Penyakit
The global infectious disease burden is on the order of several hundred million cases per
year. Many vector-borne diseases are climate sensitive. Malaria, dengue fever, hantavirus
pulmonary syndrome, and various forms of viral encephalitis are all in this category. All
24
these diseases are the result of arthropod-borne viruses (arboviruses) which are transmitted
to humans as a result of bites from blood-sucking arthropods.
Perubahan iklim global, terutama perubahan suhu dan curah hujan - sangat
berkorelasi dengan prevalensi vektor penyakit . Misalnya, virus yang dibawa oleh nyamuk ,
kutu , dan arthropoda lain penghisap darah, umumnya telah meningkatkan tingkat
transmisinya dengan adanya peningkatan suhu. Nyamuk Culex tarsalis membawa virus.
Persentase gigitan yang menghasilkan transmisi SLE tergantung pada suhu, laju transmisi
lebih besar pada suhu tinggi .
Ketergantungan vektor penyakit pada suhu ini juga dapat digambarkan dengan baik
pada penyakit malaria. Malaria adalah endemik di seluruh daerah tropis , dengan prevalensi
tinggi di Afrika , benua India , Asia Tenggara , dan sebagian dari Amerika Selatan, Amerika
Tengah dan Meksiko . Sekitar 2,4 miliar orang tinggal di daerah risiko , dengan 350 juta
infeksi baru terjadi setiap tahunnya , mengakibatkan sekitar 2 juta kematian , terutama pada
anak-anak . Malaria yang tidak diobati dapat menjadi penderitaan seumur hidup dengan
gejala seperti demam , sakit kepala , dan malaise .
The sensitivitas malaria terhadap iklim dapat terjadi karena sifat dari interaksi parasit
, vektor , dan host ; yang semuanya berdampak tingkat penularan pada manusia. Waktu
tumbuh yang diperlukan oleh parasit untuk berkembang penuh dalam host nyamuk (suatu
proses yang disebut sporogoni ) adalah 8-35 hari . Ketika suhu di kisaran 20 ° C hingga 27 °
C , waktu tumbuh ini menjadi lebih singkat. Curah hujan dan kelembaban udara juga sangat
berpengaruh. Kekeringan dan hujan lebat cenderung mengurangi populasi nyamuk yang
berfungsi sebagai vektor malaria . Di daerah kering daerah tropis , curah hujan yang rendah
dan kelembaban yang rendah membatasi kelangsungan hidup nyamuk . Banjir parah dapat
mengakibatkan rusaknya habitat berkembang biak bagi nyamuk vektor , sedangkan curah
hujan medium dapat meningkatkan produksi vektor .
Tambak yang terlantar dapat digunakan untuk nila merah
(Ujang Komarudin, Perekayasa Muda BBAP Ujung Batee, Aceh. Selasa, 28 September 2010)
Tambak udang yang tidak dikelola lagi biasanya disebabkan oleh gangguan penyakit, kualitas air
tidak layak, sedimentasi tambak, atau karena pemiliknya tidak mempunyai modal yang cukup.
Kondisi tambak seperti ini masih dapat direkayasa dan dikelola untuk memelihara ikan nila merah.
Budidaya jenis ikan ini ternyata mempunyai risiko yang lebih rendah.
25
Sumber: http://artaquaculture.blogspot.com/2010/09/nila-merah-untuk-tambak-idle.html ...... Diunduh
15 desember 2011
Ketidak-seimbangan Ekologis
Kolera adalah penyakit serius dan berpotensi gangguan fatal, disebabkan oleh
bakteri Vibrio cholerae . Gejala kolera meliputi diare eksplosif, muntah, dan sakit perut.
Pandemi terbaru kolera melibatkan lebih banyak daerah daripada waktu-waktu sebelumnya
pada abad kedua puluh. Peningkatan prevalensi V. cholerae sangat terkait dengan
degradasi lingkungan pesisir pantai dan laut. Perairan pesisir yang hangat dan kaya hara,
yang dihasilkan oleh perubahan iklim dan penggunaan pupuk , menyediakan lingkungan
yang ideal untuk reproduksi dan penyebaran V. cholerae . Wabah baru kolera di Bangladesh
, misalnya , berkorelasi erat dengan suhu permukaan laut yang lebih tinggi. V. cholerae
menempel pada permukaan copepoda ( krustasea ) air tawar dan laut, serta akar dan
permukaan terbuka dari tumbuhan ( tanaman air ) seperti eceng gondok yang paling
melimpah di Bangladesh.
Pengkayaan hara dan suhu hangat menimbulkan ledkaan populasi ganggang dan
kelimpahan makrofita . Melimpahnya ganggang menyediakan makanan yang berlimpah bagi
copepoda , dan banyaknya copepoda dan macrophyte menyediakan habitat yang bagus
bagi V. cholerae. Penyebaran selanjutnya dari V. cholerae ke muara dan badan air tawar
memungkinkan kontak dengan manusia yang menggunakan air ini untuk minum dan mandi .
Distribusi global patogen laut seperti V. cholerae lebih lanjut difasilitasi oleh air pembuangan
air limbah . Air limbah ini mengandung beragam patogen , termasuk V. Cholerae.
Resistensi Antibiotik dan Praktek Pertanian
Resistensi antibiotik merupakan ancaman bagi kesehatan masyarakat. Strain
resisten antibiotik Streptococcus pneumoniae, bakteri patogen bagi manusia dan merupakan
26
penyebab utama banyak infeksi, termasuk bronkitis kronis, pneumonia, dan meningitis, telah
sangat meningkat prevalensinya sejak pertengahan 1970-an. Di beberapa wilayah di dunia,
hingga 70 persen dari isolat bakteri yang diambil dari pasien terbukti resisten terhadap
penisilin dan antibiotik lainnya. Penggunaan jumlah besar antibiotik di bidang pertanian dan
perikanan tampaknya telah menjadi faktor kunci yang menyebabkan resistensi antibiotik
pada patogen hewan ternak yang kemudian juga dapat menginfeksi manusia. Salah satu
risiko yang paling serius bagi kesehatan manusia dari praktek-praktek tersebut adalah
enterococci yang resisten nancomycin. Penggunaan avoparcin, pemicu pertumbuhan
hewan, tampaknya telah dikompromikan penggunaan vankomisin, antibiotik yang efektif
terhadap bakteri multi-resisten obat.
Ketahanan Pangan dan Air.
Praktek pertanian juga dapat menimbulkan sejumlah ancaman bagui kesehatan masyarakat.
Sebagian dari hal ini berhubungan dengan jeleknya pengolaan limbah, yang mengakibatkan sejumlah
parasit dan bakteri memasuki perairan dan system suplai air minum. Hal yang lain adalah
melibatkan transfer lintas spesies pathogen-patogen yang dapat menyerang binatang dan manusia.
The most recent and spectacular example is mad cow disease, known as variant CreutzfeldtJakob disease in humans, a neuro-degenerative condition that, in humans, is ultimately fatal. The
first case of Bovine Spongiform Encephalopathy (BSE), the animal form of the disease, was
identified in Southern England in November 1981. By the fall of 2000, an outbreak had also
occurred in France, and isolated cases appeared in Germany, Switzerland, and Spain. More than
one hundred deaths in Europe were attributed to what has come to be commonly called mad cow
disease.
Pengelolaan pupuk kandang yang tidak tepat telah berdampak pada munculnya gangguan E.
coli 0157:H7 di Walkerton, Ontario, Canada. Risiko kesehatan lainnya yang berhubungan dengan
mal-fungsi agroecosystems adalah adanya gangguan periodic cryptosporidiosis, penyakit parasitis
yang disebarkan oleh limpasan permukaan (runoff) yang terkontaminasi oleh kotoran ternak yang
sakit (terinfeksi). Parasit ini menyebabkan gangguan penyakit perut dan diarrhea pada orang-orang
yang immune-competent dan diarrhea-parah dan kematian pada orang-orang yang immunecompromised.
Restorasi Ekosistem
Patologi ekosistem dalam beberapa kasus dapat dengan mudah diatasi dengan jalan
menghilangkan sumber-sumber stress. Misalnya dalam kasus-kasus degradasi ekosistem yang
diakibatkan oleh penambahan bahan kimia toksik, maka penghilangan stress ini dapat memulihkan
kembali kesehatan ekosistem.
Restorasi Agroekologis
Agroecological restoration is the practice of re-integrating natural systems into agriculture in
order to maximize sustainability, ecosystem services, and biodiversity. This is one example of a
way to apply the principles of agroecology to an agricultural system. Farms cannot be restored to
a purely natural state because of the negative economic impact on farmers, but returning
processes, such as pest control to nature with the method of intercropping, allows a farm to be
more ecologically sustainable and, at the same time, economically viable. Agroecological
restoration works toward this balance of sustainability and economic viability because
27
conventional farming is not sustainable over the long run without the integration of natural
systems and because the use of land for agriculture has been a driving force in creating the
present world biodiversity crisis. Its efforts are complementary to, rather than a substitute for,
biological conservation.
“…biodiversity is just as important on farms and in fields as it is in deep river valleys or
mountain cloud forests.” FAO, 15 October 2004
Agriculture creates a conflict over the use of land between wildlife and humans. Though the
domestication of crop plants occurred 10,000 years ago, a 500% increase in the amount of
pasture and crop land over the last three hundred years has led to the rapid loss of natural
habitats. In recent years, the world community acknowledged the value of biodiversity in
treaties, such as the 1992 landmark Convention on Biological Diversity.
Reintegration
The reintegration of agricultural systems into more natural systems will result in decreased
yield and produce a more complex system, but there will be considerable gains in
biodiversity and ecosystem services.
Biodiversitas
The FAO memperkirakan bahwa lebih dari 40% dari lahan di muka bumi saat ini
digunakan untuk pertanian. Begitu banyaknya lahan yang telah dikonversi menjadi
lahan pertanian, maka hilangnya habitat telah menjadi pendorong hilangnya
keanekaragaman hayati (FAO). Hilangnya keanekaragaman hayati ini seringkali terjadi
dalam dua tahap, dengan system pertanian campuran yang dilakukan pada lahan-lahan
sempit dan kemudian dengan meluasnya penggunaan pertanian mekanik dan
monokultur. Penurunan keanekaragaman hayati lahan pertanian dapat ditelusuri dari
perubahan praktek pertanian dan peningkatan intensitas pertanian.
Peningkatan keaneka-ragaman
Heterogeneity (the diversity or complexity of the landscape) has been shown to be
associated with species diversity. For example, the abundance of butterflies has been found
to increase with heterogeneity. One important part of maintaining heterogeneity in the
spaces between different fields is made up of habitat that is not cropped, such as grass
margins and strips, scrub along field boundaries, woodland, ponds, and fallow land. These
seemingly unimportant pieces of land are crucial for the biodiversity of a farm. The presence
of field margins benefits many different taxa: the plants attract herbivorous insects, will
which attract certain species of birds and those birds will attract their natural predators.
Also, the cover provided by the no cropped habitat allows the species that need a large
range to move across the landscape.
Monokultur
In the absence of cover, species face a landscape in which their habitat is greatly
fragmented. The isolation of a species to a small habitat that it can’t safely wander from can
create a genetic bottleneck, decreasing the resilience of the particular population, and be
another factor leading to the decline of the total population of the species. Monoculture,
the practice of producing a single crop over a wide area, causes fragmentation. In
28
conventional farming, monoculture, such as with rotations of corn and soybean crops
planted in alternating growing seasons, is used so that very high yields can be produced.
After the mechanization of farming, monoculture became a standard practice in corn-beans
rotation, and had broad implications for the long-term sustainability and biodiversity of
farms. Whereas organic fertilizers, had kept the soil’s nutrients fixed to the ecosystem, the
introduction of monoculture removed the nutrients and farmers compensated for that loss
by using inorganic fertilizers. It is estimated that humans have doubled the rate of nitrogen
input into the nitrogen cycle, mostly since 1975. As a result, the biological processes that
controlled the way crops used the nutrients changed and the leached nitrogen from
farmland soils has become a source of pollution.
Pertanian Organik
Organic farming is defined in different legal terms by different nations, but its main
distinction from conventional farming is that it prohibits the use of synthetic chemicals in
crop and livestock production. Often, it also includes diverse crop rotations and provides
non-cropped habitat for insects that provide ecosystem services, such as pest control and
pollination. However, it is merely encouraged that organic farmers follow those kinds of
wildlife friendly practices, and as a result there is a great difference between the ecosystem
services that similarly sized but distinctly managed organic farms provide. A recent review of
the 76 studies concerning the relationship between biodiversity and organic farming listed
three practices associated with organic farming that accounted for the higher biodiversity
counts found in organic farms as compared to conventional farms.
1. Prohibition/reduced use of chemical pesticides and inorganic fertilizers is likely to
have a positive impact through the removal of both direct and indirect negative
effects on arable plants, invertebrates and vertebrates.
2. Sympathetic management of non-crop habitats and field margins can enhance
diversity and abundance of arable plants, invertebrates, birds and mammals.
3. Preservation of mixed farming is likely to positively impact farmland biodiversity
through the provision of greater habitat heterogeneity at a variety of temporal and
spacial scales within the landscape.
Degradasi Ekosistem
Degradasi ekosistem: Degradasi atau destruksi lingkungan alam sekala luas. Kalau suatu
ekosistem mengalami gangguan akibat dari peristiwa alam atau kegiatan manusia maka sangat sulit
untuk menghitung dampak yang dialami oleh seluruh alam. Kalau dua atau lebih ekosistem
mengalami degradasi maka peluang terjadinya destruktif sinergistik akan berlipat-ganda. Ecosistemekosistem di banyak daerah akan terancam, dengan segala kekayaan biologisnya dan potensi
manfaat materialnya. (Source: WPR)
Degradation of Coastal Environments and Potential Effects on Coastal aquaculture
(Guidelines for the promotion of environmental management of coastal aquaculture development (based
on a review of selected experiences and concepts). FAO Fisheries Technical Paper. No. 328. Rome, FAO.
1992. 122 p. )
29
The coastal zone as an economic entity provides sites for a wide range of activities, such as
agriculture (e.g., rice, coco palm, bananas), forestry (e.g., mangrove, nypa palm), fisheries and
aquaculture, human settlements, manufacturing and extractive industries (e.g., sand mining, oil,
minerals), waste disposal, ports and marine transportation, land transportation infrastructure,
water control and supply projects, shore protection works, tourism and recreation. The multiple
resource uses or activities in coastal areas may produce a variety of changes in environmental
or socio-economic conditions, which in turn may result in an impact of social concern.
It is important to recognize that in many coastal areas, pollution and habitat modification
stemming from human activities other than aquaculture are increasingly affecting resource use
productivity of aquaculture as well as limiting success and development possibilities of the
aquaculture industry.
Sumber: http://www.fao.org/docrep/T0697E/t0697e04.htm ..... diunduh 20 Desember 2011
Degradasi Ekosistem: Tanggungjawab Moral terhadap Planet Bumi
Kegiatan manusia telah berdampak pada degradasi ekosistem. Karena planet, binatang dan
lingkungan semuanya saling berinteraksi, maka perubahan yang berlangsung dalam ekosistem
akan mempunyai dampak negative terhadap kehidupan dan planet bumi ini. Oleh karena itu,
kita semua wajib untuk mengendalikan kegiatan-kegiatan manusia guna mewujudkan
kelestarian planet bumi di masa mendatang yang lebih nyaman dan lebih aman. Kita semua
manusia perlu bernafas dalam udara segar, hal yang tidak mungkin terjadi kalau pembakaran
bahan bakar fosil masih berlebihan. Hal ini akan menyesakkan nafas berbagai spesies
oprganisme dan mengakibatkan perubahan iklim yang menjadi ekstrim.
Aktivitas manusia telah mengakibatkan perubahan pola lingkungan hidup dunia. Aktivitas
lainnya yang juga menyebabkan kerusakan ekosistem adalah perikanan, pemanfaatan air tawar,
30
dan penebangan /penggundulan huitan. Penebangan hutan telah mengakibatkan kandungan CO2
atmosfir meningkat dan mengakibatkan punahnya beberapa spesies. Siklus lingkungan telah
mengalami perubahan drastic akibat kegiatan manusia. Ada kerusakan parah pada lapisan ozon.
Bagaimana kita akan dilindungi dari bahaya radiasi ultraviolet?
Bagaimana kita harus melindungi lapisan ozon ini? Masing-masing dari kita semua , harus
mengambil rtanggung-jawab ini untuk mereduksi emisi CO2 dengan jalan menanam lebih banyak
pohon sehingga jalur-jalur hijau melindungi semua kehidupan. Oleh karena itu penyelamatan
planet bumi dari kepunahan berada di tangan kita manusia semuanya.
(Sumber: http://EzineArticles.com/3784225)
Gambar berikut ini menunjukkan keterkaitan antara tekanan penduduk, fenomena
kekeringan, proses-proses degradasi, desertification, dan kerentanan pangan.
Sumber: http://ag.arizona.edu/~lmilich/envsec.html ….. diunduh 2/7/2011
Keterkaitan antara Ketahanan pangan rumahtangga dan Ketahanan Lingkungan:
Siklus Kemiskinan-Degradasi Lingkungan
31
Sumber: http://ag.arizona.edu/~lmilich/envsec.html ….. diunduh 2/7/2011
Mencegah Degradasi Ekosistem
Memulihkan kembali degradasi ekosistem sangatlah sulit, dan banyak sekali risiko kesehatan
manusia telah bermunculan akibat dari hilangnya kesehatan ekosistem, pendekatan yang paluing
efektif sebenarnya adalah mencegah terjadinya kerusakan ekosistem. Akan tetapi pendekatan
seperti ini tidak mudah dilaksanakan, ada beragam kendala menghadang. Di Negara-negara sedang
berkembang dan Negara-negara maju ada inklinasi yang kuat untuk melanjutkan pertumbuhan
ekonominya, meskipun dengan biaya mahal berupa kerusakan lingkungan yang parah. Terlepas dari
motivasi ego-kemandirian, argumentasi yang diambil ialah bahwa pertumbuhan ekonomi
mempunyai banyak manfaat nyata bagi kesehatan, seperti penyediaan sarana yang lebih efisien
untuk distribusi pangan, penyediaan pangan yang lebih baik, dan penyediaan layanan kesehatan
yang elbih bagus, serta pendanaan untuk penelitian memperbaiki standard kehidupan. Ini semuanya
memang manfaat dari pembangunan ekonomi, dan telah berhasil meningkatkan status kesehatan
penduduk dunia.
However, at the dawn of the twenty-first century, the past is not necessarily the best guide
to the future. The human population is at an alltime high, and associated pressures of human activity
have led to increasing degradation of the earth's ecosystems. As ultimately healthy ecosystems are
essential for life of all biota, including humans, current global and regional trends are ominous.
Under these circumstances, a tradeoff between immediate material gains and long-term
32
sustainability of humans on the planet may be the only option. If so, the solution to sustaining
human health and ecosystem health becomes one of devising a new politic that places sustaining
lifesupport systems as a precondition for betterment of the human condition.
Pertanian = Agriculture
The word agriculture is the English adaptation of Latin agricultūra, from ager, "a field", and
cultūra, "cultivation" in the strict sense of "tillage of the soil". Thus, a literal reading of the
word yields "tillage of a field / of fields".
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and
other products used to sustain life. Agriculture was the key implement in the rise of sedentary
human civilization, whereby farming of domesticated species created food surpluses that nurtured
the development of civilization. The study of agriculture is known as agricultural science. Agriculture
is also observed in certain species of ant and termite, but generally speaking refers to human
activities.
The history of agriculture dates back thousands of years, and its development has been
driven and defined by greatly different climates, cultures, and technologies. However, all farming
generally relies on techniques to expand and maintain the lands suitable for raising domesticated
species. For plants, this usually requires some form of irrigation, although there are methods of
dryland farming; pastoral herding on rangeland is still the most common means of raising livestock.
In the developed world, industrial agriculture based on large-scale monoculture has become the
dominant system of modern farming, although there is growing support for sustainable agriculture
(e.g. permaculture or organic agriculture).
Modern agronomy, plant breeding, pesticides and fertilizers, and technological improvements have sharply increased
yields from cultivation, but at the same time have caused widespread ecological damage and negative human health
effects. Selective breeding and modern practices in animal husbandry such as intensive pig farming have similarly
increased the output of meat, but have raised concerns about animal cruelty and the health effects of the antibiotics,
growth hormones, and other chemicals commonly used in industrial meat production.
The major agricultural products can be broadly grouped into foods, fibers, fuels, and raw
materials. In the 21st century, plants have been used to grow biofuels, biopharmaceuticals,
bioplastics, and pharmaceuticals. Specific foods include cereals, vegetables, fruits, and meat. Fibers
include cotton, wool, hemp, silk and flax. Raw materials include lumber and bamboo. Other useful
materials are produced by plants, such as resins. Biofuels include methane from biomass, ethanol,
and biodiesel. Cut flowers, nursery plants, tropical fish and birds for the pet trade are some of the
ornamental products.
Sistem Produksi Tanaman
Cropping systems vary among farms depending on the available resources and constraints;
geography and climate of the farm; government policy; economic, social and political pressures; and
the philosophy and culture of the farmer.[47][48] Shifting cultivation (or slash and burn) is a system in
33
which forests are burnt, releasing nutrients to support cultivation of annual and then perennial crops
for a period of several years.[49]
Then the plot is left fallow to regrow forest, and the farmer moves to a new plot, returning
after many more years (10-20). This fallow period is shortened if population density grows, requiring
the input of nutrients (fertilizer or manure) and some manual pest control. Annual cultivation is the
next phase of intensity in which there is no fallow period. This requires even greater nutrient and
pest control inputs.
Further industrialization lead to the use of monocultures, when one cultivar is planted on a
large acreage. Because of the low biodiversity, nutrient use is uniform and pests tend to build up,
necessitating the greater use of pesticides and fertilizers.[48] Multiple cropping, in which several
crops are grown sequentially in one year, and intercropping, when several crops are grown at the
same time are other kinds of annual cropping systems known as polycultures.
In tropical environments, all of these cropping systems are practiced. In subtropical and arid
environments, the timing and extent of agriculture may be limited by rainfall, either not allowing
multiple annual crops in a year, or requiring irrigation. In all of these environments perennial crops
are grown (coffee, chocolate) and systems are practiced such as agroforestry. In temperate
environments, where ecosystems were predominantly grassland or prairie, highly productive annual
cropping is the dominant farming system.
“The last century has seen the intensification, concentration and specialization of
agriculture, relying upon new technologies of agricultural chemicals (fertilizers and
pesticides), mechanization, and plant breeding (hybrids and GMO's). In the past few
decades, a move towards sustainability in agriculture has also developed, integrating ideas
of socio-economic justice and conservation of resources and the environment within a
farming system.[50][51] This has led to the development of many responses to the
conventional agriculture approach, including organic agriculture, urban agriculture,
community supported agriculture, ecological or biological agriculture, integrated farming
and holistic management, as well as an increased trend towards agricultural
diversification”.
Sistem Produksi Ternak
Animals, including horses, mules, oxen, camels, llamas, alpacas, and dogs, are often used to
help cultivate fields, harvest crops, wrangle other animals, and transport farm products to buyers.
Animal husbandry not only refers to the breeding and raising of animals for meat or to harvest
animal products (like milk, eggs, or wool) on a continual basis, but also to the breeding and care of
species for work and companionship. Livestock production systems can be defined based on feed
source, as grassland - based, mixed, and landless.
Grassland based livestock production relies upon plant material such as shrubland,
rangeland, and pastures for feeding ruminant animals. Outside nutrient inputs may be used,
however manure is returned directly to the grassland as a major nutrient source. This system is
particularly important in areas where crop production is not feasible because of climate or soil,
representing 30-40 million pastoralists.[49] Mixed production systems use grassland, fodder crops and
grain feed crops as feed for ruminant and monogastic (one stomach; mainly chickens and pigs)
livestock. Manure is typically recycled in mixed systems as a fertilizer for crops. Approximately 68%
of all agricultural land is permanent pastures used in the production of livestock.
34
Landless systems rely upon feed from outside the farm, representing the de-linking of crop
and livestock production found more prevalently in OECD member countries. In the U.S., 70% of the
grain grown is fed to animals on feedlots. Synthetic fertilizers are more heavily relied upon for crop
production and manure utilization becomes a challenge as well as a source for pollution.
Menurut Jongbloed and Lenis (1995), beberapa pendekatan untuk mereduksi limbah ternak dan
pencemaran lingkungan adalah:
1. Supply nutrients to the required level. This can be accomplished by better knowledge of
nutrient availability (N, P) in the feed, a better knowledge of the animals requirement
and a better agreement of supply and requirement.
2. Enhance digestibility of P and protein. Use of microbial phytase to improve digestibility
of P reduces needs for supplementation; enzyme treatment of non-starch
polysaccharides; reduce anti-nutritional factors through treatment of ingredients and
processing of complete diets.
3. Change feedstuff composition. For example selection of highly digestible sources of P
(mono-calcium phosphate rather than di-calcium); use of amino acid supplementation
and reduction in protein levels.
4. Memperbaiki efisiensi pakan.
Dampak lingkungan lainnya:
1. Levels of potassium supply exceed demand by a factor of 3-5 and levels in fresh water
can exceed accepted levels by a factor of 2-4.
2. High moisture level of livestock waste increases transport costs for disposal.
3. Although feed additives may reduce excretion of N and P as a result of better feed
conversion, copper and zinc growth promotants can accumulate in soils.
4. Free-ranging pigs requiring more fibre in the diet have lower feed conversion and more
waste per unit of meat produced.
5. Specific pathogen-free herds can improve feed conversion by 10-15 percent.
Sumber: Jongbloed and Lenis (1995)
35
Pertanian-Ekologis = Ecoagriculture
Ecoagriculture menggambarkan lanskap yang mendukung produksi pertanian dan
konservasi keanekaragaman hayati, bekerja secara harmonis untuk meningkatkan
kesejahteraan masyarakat pedesaan. Sementara itu, banyak masyarakat pedesaan yang secara
mandiri telah menerapkan system Ecoagriculture selama ribuan tahun, selama abad terakhir
ini banyak lanskap ini telah dikonversi menjadi beragam penggunaan lahan; beberapa daerah
menerapkan praktek-praktek pertanian intensif tanpa memperhatikan dampaknya terhadap
keanekaragaman hayati, dan daerah lainnya dilindungi sepenuhnya menjadi kawasan lindung
atau daerah perlindungan DAS. Suatu gerakan Ecoagriculture baru sekarang mendapatkan
momentum untuk menyatukan pengelola lahan dan pemangku kepentingan lainnya untuk
menemukan cara yang kompatibel untuk melestarikan keanekaragaman hayati sambil juga
meningkatkan produksi pertanian.
"Ecoagriculture" is a term coined in 2000 (by Sara Scherr and Jeffrey McNeely) to convey
a vision of rural communities managing their resources to jointly achieve three broad
goals at a landscape scale — what we refer to as the “three pillars” of ecoagriculture:
 Enhance rural livelihoods;
 Conserve or enhance biodiversity and ecosystem services; and
 Develop more sustainable and productive agricultural systems.
Ecoagriculture is both a conservation strategy and a rural development strategy.
Ecoagriculture recognizes agricultural producers and communities as key stewards of ecosystems
and biodiversity and enables them to play those roles effectively. Ecoagriculture applies an
integrated ecosystem approach to agricultural landscapes to address all three pillars, drawing on
diverse elements of production and conservation management systems. Meeting the goals of
ecoagriculture usually requires collaboration or coordination between diverse stakeholders who are
collectively responsible for managing key components of a landscape.
As an alternative strategy to industrial agriculture, an ecoagriculture approach works by
mimicking natural systems to create a new ecosystem, one consisting mainly of perennials and
indigenous species. There are many names for ecoagricultural systems; permaculture, natural
systems agriculture, agroecology, and while doctrinaires will expound the differences between these
labels, all work on the same principals and emulate basic analogous concepts. By mimicking and recreating an eco-system, biodiversity, stability, fertility, resilience and resistance are increased, thereby strengthening the overall agricultural system. Chemical additions are not required as the system
is closed and entirely self-supportive, additionally needed amendments will be provided from
organic by-products of the system. Ecoagriculture systems have been shown to be effective in both
climate change mitigation and adaptation, while being extremely productive as a food source.
Ecoagriculture systems “have been described as domesticated ecosystems” . The premise
works similarly to a forest, or a prairie, or any other ecosystem. A forest is an entirely contained
system, each individual part making the whole stronger. A forest does not require outside fertilizers
or pesticides or irrigation, yet nutrients in the soil, insect ratios, water are typically keep in proper
balance. “This system, thus, maintains its own health, runs on the sun's energy, recycles nutrients,
and at no expense to the planet or people.” Using these concepts, ecoagriculture designs a system
allowing these processes to work with the land, to achieve the desired outcome of an increased,
diverse food supply.
36
Pohon ditanam pada guludan untuk memanfaatkan air hujan yang tertampung pada parit (swale)
Sumber: http://climatelab.org/Ecoagriculture ..... diunduh 30/6/2011
Ecoagriculture is both a conservation strategy and a rural development strategy.
Ecoagriculture recognizes agricultural producers and communities as key stewards of ecosystems
and biodiversity and enables them to play those roles effectively. Ecoagriculture applies an
integrated ecosystem approach to agricultural landscapes to address all three pillars -- conserving
biodiversity, enhacing agricultural production, and improving livelihoods -- drawing on diverse
elements of production and conservation management systems. Meeting the goals of ecoagriculture
usually requires collaboration or coordination between diverse stakeholders who are collectively
responsible for managing key components of a landscape.
Pertanian Berkelanjutan = Sustainable agriculture
Sustainable agriculture is the practice of farming using principles of ecology, the study of
relationships between organisms and their environment. It has been defined as "an integrated
system of plant and animal production practices having a site-specific application that will last over
the long term:
 Satisfy human food and fiber needs
 Make the most efficient use of non-renewable resources and on-farm resources and
integrate, where appropriate, natural biological cycles and controls
 Sustain the economic viability of farm operations
 Enhance the quality of life for farmers and society as a whole.”[1]
37
A growing movement has emerged during the past two decades to question the role of the
agricultural establishment in promoting practices that contribute to these social problems. Today
this movement for sustainable agriculture is garnering increasing support and acceptance within
mainstream agriculture. Not only does sustainable agriculture address many environmental and
social concerns, but it offers innovative and economically viable opportunities for growers, laborers,
consumers, policymakers and many others in the entire food system.
Sustainable agriculture integrates three main goals--environmental health, economic
profitability, and social and economic equity. A variety of philosophies, policies and practices have
contributed to these goals. People in many different capacities, from farmers to consumers, have
shared this vision and contributed to it. Despite the diversity of people and perspectives, the
following themes commonly weave through definitions of sustainable agriculture.
Sustainable agriculture is said to offer three main goals that industrial agriculture has not been successfully
accounting for – environmental health and diversity, economic profitability, and social and economic equity. In
summary, it looks to promote harmony between agriculture and social responsibility so that the ability of future
generations to meet their own needs is not obstructed. In reality, the growth rate of the global human population is
rapid, but not something the agricultural industry can’t keep up with.
Sumber: http://lidomain.blogspot.com/ ….. diunduh 30/6/2011
Sustainability rests on the principle that we must meet the needs of the present without
compromising the ability of future generations to meet their own needs. Therefore, stewardship of
both natural and human resources is of prime importance. Stewardship of human resources includes
consideration of social responsibilities such as working and living conditions of laborers, the needs of
rural communities, and consumer health and safety both in the present and the future. Stewardship
of land and natural resources involves maintaining or enhancing this vital resource base for the long
term.
38
Model Usahatani berkelanjutan
To be sustainable, inputs must be less than outputs. Inputs include fuel and all forms of
energy, labour and raw materials. Even treatment of wastes must not consume excessive
energy. For a farmer to practice sustainable agriculture, he must derive a reasonable
income from his efforts. The only purchased inputs are corn and other feed ingredients.
From here, all 'wastes' are recycled. Dung, carcasses, etc are all composted and made into
high quality humus. Using humus and compost tea and proper management, an acre of land
can produce 30 tonnes of high protein napia grass. This is fed to goats and fish. Using humus
and compost tea, and selecting low-nitrogen demanding heritage seeds, seperti kacangkacangan, bayam, terung, dll. we can produce abundant market vegetables.
Model usahatani berkelanjutan sekala mikro (Sumber: http://dqfarm.blogspirit.com/web/ ….. diunduh 30/6/2011)
A systems perspective is essential to understanding sustainability. The system is envisioned
in its broadest sense, from the individual farm, to the local ecosystem, and to communities affected
by this farming system both locally and globally. An emphasis on the system allows a larger and
more thorough view of the consequences of farming practices on both human communities and the
environment. A systems approach gives us the tools to explore the interconnections between
farming and other aspects of our environment.
A systems approach also implies interdisciplinary efforts in research and education. This
requires not only the input of researchers from various disciplines, but also farmers, farmworkers,
consumers, policymakers and others.
Making the transition to sustainable agriculture is a process. For farmers, the transition to
sustainable agriculture normally requires a series of small, realistic steps. Family economics
and personal goals influence how fast or how far participants can go in the transition. It is
39
important to realize that each small decision can make a difference and contribute to
advancing the entire system further on the "sustainable agriculture continuum." The key to
moving forward is the will to take the next step.
Finally, it is important to point out that reaching toward the goal of sustainable agriculture is
the responsibility of all participants in the system, including farmers, laborers, policymakers,
researchers, retailers, and consumers. Each group has its own part to play, its own unique
contribution to make to strengthen the sustainable agriculture community.
The specific strategies for realizing these broad themes or goals of systems . The strategies
are grouped according to three separate though related areas of concern: Farming and Natural
Resources, Plant and Animal Production Practices, and the Economic, Social and Political Context.
They represent a range of potential ideas for individuals committed to interpreting the vision of
sustainable agriculture within their own circumstances.
Usaha Pertanian dan Sumberdaya Alam
The physical aspects of sustainability are partly understood. Practices that can cause longterm damage to soil include excessive tillage (leading to erosion) and irrigation without adequate
drainage (leading to salinization). Long-term experiments have provided some of the best data on
how various practices affect soil properties essential to sustainability. The most important factors for
an individual site are sun, air, soil and water. Of the four, water and soil quality and quantity are
most amenable to human intervention through time and labour.
Sistem Produksi Primer
Plants produce plant matter from soil nutrients, water and carbon dioxide, using the energy
of light. It is called primary production. The diagram shows the carbon flows (is equal to
energy flows). At left one sees a plant receiving light and CO2 from the air and returning
oxygen. At night, when there is no sunlight, plants respire like animals do, taking up oxygen
and returning CO2. Surprisingly, a large proportion of a plant's primary production (50%)
disappears underground, where it grows the root system and feeds soil organisms. Only 50%
is used for above-ground growth. Of this, between 10 and 40% is used for growing,
depending on plant type, age and kind of harvesting. If the plant is grazed regularly, the
grown biomass will be grazed, amounting to no more than 40%. The remaining 10% is lost by
leaf drop. This leaf litter is decomposed by fungi and bacteria, contributing energy to the soil
biota, while returning nutrients to the plant
40
Sumber: http://www.seafriends.org.nz/enviro/soil/ecology.htm ..... diunduh 30/6/2011
Udara dan sinar matahari tersedia di mana-mana di muka Bumi ini, namun tanaman
juga tergantung pada ketersediaan hara dalam tanah dan ketersediaan air dalam tanah. Ketika
petani menanam dan panen tanaman , mereka mengambil sejumlah hara dari dalam tanah .
Tanpa pengembalian sejumlah hara ke tanah, maka tanah akan mengalami penurunan tingkat
kesuburannya dan dapat berdampak pada penurunan pertumbuhan dan hasil panen. Pertanian
berkelanjutan tergantung pada pengelolaan tanah dan meminimalkan penggunaan sumber
daya yang tidak terbarukan, seperti gas alam (digunakan dalam mengkonversi nitrogen
atmosfer menjadi pupuk sintetis) , atau bijih mineral ( misalnya fosfat ) . Sumber nitrogen
yang dapat tersedia secara berkelanjutan , meliputi:
1. Daur ulang limbah tanaman dan ternak atau kotoran manusia yang telah diolah
2. Menanam tanaman legume dan hijauan seperti kacang-kacangan atau alfalfa yang
membentuk mampu bersimbiosis dengan bakteri fiksasi nitrogen yang disebut
rhizobia
3. Produksi industri pupuk nitrogen dengan proses Haber menggunakan hidrogen , yang
saat ini berasal dari gas alam , tetapi hidrogen ini sebenarnya dapat dibuat dengan
elektrolisis air menggunakan listrik ( mungkin dari sel surya atau kincir angin )
4. Rekayasa genetik tanaman non - legume untuk membentuk simbiosis penambat
nitrogen atau fiksasi nitrogen tanpa simbion mikroba .
The last option was proposed in the 1970s, but is only recently becoming feasible.
Sustainable options for replacing other nutrient inputs (phosphorus, potassium, etc.) are more
limited. More realistic, and often overlooked, options include long-term crop rotations, returning to
natural cycles that annually flood cultivated lands (returning lost nutrients indefinitely) such as the
Flooding of the Nile, the long-term use of biochar, and use of crop and livestock landraces that are
adapted to less than ideal conditions such as pests, drought, or lack of nutrients. Crops that require
41
high levels of soil nutrients can be cultivated in a more sustainable manner if certain fertilizer
management practices are adhered to.
Air - Pertanian
In some areas, sufficient rainfall is available for crop growth, but many other areas require
irrigation. For irrigation systems to be sustainable they require proper management (to avoid
salinization) and must not use more water from their source than is naturally replenished, otherwise
the water source becomes, in effect, a non-renewable resource. Improvements in water well drilling
technology and submersible pumps combined with the development of drip irrigation and low
pressure pivots have made it possible to regularly achieve high crop yields where reliance on rainfall
alone previously made this level of success unpredictable. However, this progress has come at a
price, in that in many areas where this has occurred, such as the Ogallala Aquifer, the water is being
used at a greater rate than its rate of recharge.
Suplai dan Penggunaan Air
An extensive water storage and transfer system has been established which has allowed
crop production to expand to very arid regions. In drought years, limited surface water
supplies have prompted overdraft of groundwater and consequent intrusion of salt water, or
permanent collapse of aquifers. Periodic droughts, some lasting up to 50 years, have
occurred in any areas. Several steps should be taken to develop drought-resistant farming
systems even in "normal" years, including both policy and management actions: 1)
improving water conservation and storage measures, 2) providing incentives for selection of
drought-tolerant crop species, 3) using reduced-volume irrigation systems, 4) managing
crops to reduce water loss, or 5) not planting at all.
Kualitas Air.
The most important issues related to water quality involve salinization and contamination of
ground and surface waters by pesticides, nitrates and selenium. Salinity has become a
problem wherever water of even relatively low salt content is used on shallow soils in arid
regions and/or where the water table is near the root zone of crops. Tile drainage can
remove the water and salts, but the disposal of the salts and other contaminants may
negatively affect the environment depending upon where they are deposited. Temporary
solutions include the use of salt-tolerant crops, low-volume irrigation, and various
management techniques to minimize the effects of salts on crops. In the long-term, some
farmland may need to be removed from production or converted to other uses. Other uses
include conversion of row crop land to production of drought-tolerant forages, the
restoration of wildlife habitat or the use of agroforestry to minimize the impacts of salinity
and high water tables
Indicators for sustainable water resource development are: ¤ Internal renewable water
resources. This is the average annual flow of rivers and groundwater generated from endogenous
precipitation, after ensuring that there is no double counting. It represents the maximum amount of
water resource produced within the boundaries of a country. This value, which is expressed as an
average on a yearly basis, is invariant in time (except in the case of proved climate change). The
indicator can be expressed in three different units: in absolute terms (km3/yr), in mm/yr (it is a
measure of the humidity of the country), and as a function of population (m3/person per yr).
42
¤
¤
¤
Global renewable water resources. This is the sum of internal renewable water
resources and incoming flow originating outside the country. Unlike internal resources,
this value can vary with time if upstream development reduces water availability at the
border. Treaties ensuring a specific flow to be reserved from upstream to downstream
countries may be taken into account in the computation of global water resources in
both countries.
Dependency ratio. This is the proportion of the global renewable water resources
originating outside the country, expressed in percentage. It is an expression of the level
to which the water resources of a country depend on neighbouring countries.
Water withdrawal. In view of the limitations described above, only gross water
withdrawal can be computed systematically on a country basis as a measure of water
use. Absolute or per-person value of yearly water withdrawal gives a measure of the
importance of water in the country's economy. When expressed in percentage of water
resources, it shows the degree of pressure on water resources. A rough estimate shows
that if water withdrawal exceeds a quarter of global renewable water resources of a
country, water can be considered a limiting factor to development and, reciprocally, the
pressure on water resources can have a direct impact on all sectors, from agriculture to
environment and fisheries.
Tanah-pertanian
Soil erosion is fast becoming one of the worlds greatest problems. It is estimated that "more
than a thousand million tonnes of southern Africa's soil are eroded every year. Experts predict that
crop yields will be halved within thirty to fifty years if erosion continues at present rates." Soil
erosion is not unique to Africa but is occurring worldwide. The phenomenon is being called Peak Soil
as present large scale factory farming techniques are jeopardizing humanity's ability to grow food in
the present and in the future. Without efforts to improve soil management practices, the availability
of arable soil will become increasingly problematic.
Beberapa teknik pengelolaan tanah
1.
Pertanian tanpa olah tanah (No-till farming)
2.
Keyline design
3.
Tumbuhan penahan angin untuk melindungi tanah
4.
Mengembalikan bahan organic ke dalam tanah
5.
Menghentikan penggunaan pupuk-pupuk kima
6.
Melindungi tanah dari air runoff..
Berfungsinya ekosistem tanah
Chemical decomposing activity can be found throughout the soil, but it is most active in five
special areas. They are the arenas where activity concentrates. The drilosphere is the
workplace of earth worms. As can be seen from the top right drawing, worms leave a funnelshaped business end on top of previous funnels. Earth is cast on top and to the side,
covering leaf litter in a loose fashion. In the oxygen-rich moisture, other organisms find
shelter or actively take part in some of the process. Rainwater dissolves nitrates, DOC
(Dissolved Organic Carbon) and transports it down the worm hole.
The detritusphere works where leaf litter is moist and rich in oxygen. Here fungi can work
efficiently, decomposing cellulose while taking oxygen in and respirating carbon dioxide.
Inside anoxic corners of leaf structure, bacteria convert nitric oxides to nitrogen.
43
Sumber:
http://www.seafriends.org.nz/enviro
/soil/ecology.htm ..... diunduh
30/6/2011
Where masses of young roots are found, activity is high in the porosphere of the soil. Pores are
necessary to hold water and to transport oxygen and carbon dioxide. Aggregates of soil are pierced
by hair roots (yellow) and covered in hyphae of fungi (purple). By the transport channels from
worms and other organisms, water, nitrates, phosphorus and dissolved organic carbon compounds
leach from the top down.
In the aggregatusphere, sand and clay particles form enclosed workshops for bacteria. Many
chemical processes happen here, producing nitrates (NO3-), ammonia (NH4+), carbon dioxide (CO2),
nitric oxides and more. Many compounds are transported by the fine hyphae to other places.
44
Sumber:: http://www.seafriends.org.nz/enviro/soil/ecology.htm ..... diunduh 30/6/2011
The rhizosphere is the area directly around hair roots. This is a special place because hair
roots bring food and oxygen, enabling the micro organisms to work faster than anywhere else. A
continuous flow of water is caused, as water is absorbed by these roots, drawing with it dissolved
substances. As these hair roots grow, they intrude into other aggregatuspheres, find nutrients, get
eaten, and other fine roots take their place. The soil is in a continuous state of decomposition,
provided moisture and oxygen are available.
Udara-pertanian
Many agricultural activities affect air quality. These include smoke from agricultural burning;
dust from tillage, traffic and harvest; pesticide drift from spraying; and nitrous oxide emissions from
the use of nitrogen fertilizer. Options to improve air quality include incorporating crop residue into
the soil, using appropriate levels of tillage, and planting wind breaks, cover crops or strips of native
perennial grasses to reduce dust.
Ekonomi - Pertanian
Socioeconomic aspects of sustainability are also partly understood. Regarding less
concentrated farming, the best known analysis is Netting's study on smallholder systems through
history.[12] The Oxford Sustainable Group defines sustainability in this context in a much broader
form, considering effect on all stakeholders in a 360 degree approach
Given the finite supply of natural resources at any specific cost and location, agriculture that
is inefficient or damaging to needed resources may eventually exhaust the available resources or the
ability to afford and acquire them. It may also generate negative externality, such as pollution as
well as financial and production costs.
The way that crops are sold must be accounted for in the sustainability equation. Food sold
locally does not require additional energy for transportation (including consumers). Food sold at a
remote location, whether at a farmers' market or the supermarket, incurs a different set of energy
cost for materials, labour, and transport.
Metode-metode Pertanian
45
What grows where and how it is grown are a matter of choice. Two of the many possible
practices of sustainable agriculture are crop rotation and soil amendment, both designed to ensure
that crops being cultivated can obtain the necessary nutrients for healthy growth. Soil amendments
would include using locally available compost from community recycling centers. These community
recycling centers help produce the compost needed by the local organic farms.
Many scientists, farmers, and businesses have debated how to make agriculture sustainable.
Using community recycling from yard and kitchen waste utilizes a local area's commonly available
resources. These resources in the past were thrown away into large waste disposal sites, are now
used to produce low cost organic compost for organic farming. Other practices includes growing a
diverse number of perennial crops in a single field, each of which would grow in separate season so
as not to compete with each other for natural resources.[13] This system would result in increased
resistance to diseases and decreased effects of erosion and loss of nutrients in soil. Nitrogen fixation
from legumes, for example, used in conjunction with plants that rely on nitrate from soil for growth,
helps to allow the land to be reused annually. Legumes will grow for a season and replenish the soil
with ammonium and nitrate, and the next season other plants can be seeded and grown in the field
in preparation for harvest.
Monoculture, a method of growing only one crop at a time in a given field, is a very
widespread practice, but there are questions about its sustainability, especially if the same crop is
grown every year. Today it is realized to get around this problem local cities and farms can work
together to produce the needed compost for the farmers around them. This combined with growing
a mixture of crops (polyculture) sometimes reduces disease or pest problems but polyculture has
rarely, if ever, been compared to the more widespread practice of growing different crops in
successive years (crop rotation) with the same overall crop diversity. Cropping systems that include a
variety of crops (polyculture and/or rotation) may also replenish nitrogen (if legumes are included)
and may also use resources such as sunlight, water, or nutrients more efficiently (Field Crops Res.
34:239).
Replacing a natural ecosystem with a few specifically chosen plant varieties reduces the
genetic diversity found in wildlife and makes the organisms susceptible to widespread disease. The
Great Irish Famine (1845–1849) is a well-known example of the dangers of monoculture. In practice,
there is no single approach to sustainable agriculture, as the precise goals and methods must be
adapted to each individual case. There may be some techniques of farming that are inherently in
conflict with the concept of sustainability, but there is widespread misunderstanding on impacts of
some practices. Today the growth of local farmers' markets offer small farms the ability to sell the
products that they have grown back to the cities that they got the recycled compost from. By using
local recycling this will help move people away from the slash-and-burn techniques that are the
characteristic feature of shifting cultivators are often cited as inherently destructive, yet slash-andburn cultivation has been practiced in the Amazon for at least 6000 years;[15] serious deforestation
did not begin until the 1970s, largely as the result of Brazilian government programs and policies.[16]
To note that it may not have been slash-and-burn so much as slash-and-char, which with the
addition of organic matter produces terra preta, one of the richest soils on Earth and the only one
that regenerates itself.
There are also many ways to practice sustainable animal husbandry. Some of the key tools to
grazing management include fencing off the grazing area into smaller areas called paddocks,
lowering stock density, and moving the stock between paddocks frequently.
Several attempts have been made to produce an artificial meat, using isolated tissues to
produce it in vitro; Jason Matheny's work on this topic, which in the New Harvest project, is one of
the most commented.[18]
46
Perlakuan Tanah pertanian
“Pengasapan Tanah” dapat digunakan sebagai alternatif ekologis menggantikan
bahan kimia untuk sterilisasi tanah. Berbagai metode tersedia untuk mendorong uap ke dalam
tanah untuk membunuh hama dan memperbaiki kesehatan tanah. Pengkomposan limbah
domestic, limbah pertanian, sampah halaman, dan limbah organik dapur, dapat memberikan
sebagian besar kebutuhan pupuk yang diperlukan pertanian lokal. Pengomposan ini
berpotensi menjadi sumber energi yang dapat diandalkan.
Apa itu Kompos?
Kompos adalah jenis pupuk humus sehat dan kaya hara, serta menjadi bahan
pembenah tanah yang dihasilkan dari dekomposisi bahan organik. Sampah organik
digunakan untuk menggambarkan limbah yang berasal dari biomasa hidup seperti
rumput, daun, kulit sayuran, makanan yang dimasak dll. Pengomposan merupakan
sarana sederhana untuk menciptakan kondisi yang tepat untuk mempercepat proses
dekomposisi limbah organic ini.
Sumber: http://www.bionetix.co.uk/static/Compost_Info_and_Tips/ ….. diunduh 30/6/2011
Dampak eksternal
A farm that is able to "produce perpetually", yet has negative effects on environmental
quality elsewhere is not sustainable agriculture. An example of a case in which a global view may be
warranted is over-application of synthetic fertilizer or animal manures, which can improve
productivity of a farm but can pollute nearby rivers and coastal waters (eutrophication). The other
extreme can also be undesirable, as the problem of low crop yields due to exhaustion of nutrients in
the soil has been related to rainforest destruction, as in the case of slash and burn farming for
livestock feed.
47
Agricultural activities contribute strongly to eutrophication and the spread of pollutions in
the basin.
Sumber: http://www.zoologi.su.se/ekoklim/study_region.html ..... diunduh 30/6/2011
The chain of eutrophication begins with an overload of nutrients that enters the aquatic ecosystem.
This schematic show various nutrient pathways and their effects. The future half of the diagram
shows improved water quality based on better nutrient filtering.
Sumber: http://landsat.gsfc.nasa.gov/news/news-archive/soc_0017.html ..... diunduh
30/6/2011
Sustainability affects overall production, which must increase to meet the increasing food
and fiber requirements as the world's human population expands to a projected 9.3 billion people by
48
2050. Increased production may come from creating new farmland, which may ameliorate carbon
dioxide emissions if done through reclamation of desert as in the worlds, or may worsen emissions if
done through slash and burn farming. Additionally, Genetically modified organism crops show
promise for radically increasing crop yields, although many people and governments are
apprehensive of this new farming method.
Genetically modified organisms (GMOs)
Genetically modified organism (GMO) is an organism that was changed using methods of
modern biotechnology. In such organism defined gene for exactly defined characteristic
from other organism has been inserted. GMO are microorganisms (bacteria, fungi, and
viruses), plants and animals.
According to Slovene legislation ''GMO is an organism, with the exception of human beings,
or a micro-organism, in which the genetic material has been altered in a way that does not
occur naturally by mating or natural recombination.'' (Management of Genetically Modified
Organisms Act (Official Gazette of RS No. 23/2005))
According to EU legislation ''GMO means an organism, with the exception of human beings,
in which the genetic material has been altered in a way that does not occur naturally by
mating and/or natural recombination.''(Directive 2001/18/EC of the European Parliament
and of the Council of 12 March 2001 on the deliberate release into the environment of
genetically modified organisms and repealing Council Directive 90/220/EEC - Commission
Declaration)
According to international Cartagena Protocol ''Living Modified Organism (LMO) means any
living organism that possesses a novel combination of genetic material obtained through the
use of modern biotechnology.'' (Cartagena Protocol on Biosafety to the Convention on
Biological Diversity)
Sumber: http://www.biotechnology-gmo.gov.si/eng/gensko_spremenjeni_organizmi/index.html
49
Manfaat Teknologi GMO
Tanaman Pertanian
 Memperbaiki rasa dan kualitas
 Mereduksi waktu pemasakan
 Increased nutrients, yields, and stress tolerance
 Improved resistance to disease, pests, and herbicides
 New products and growing techniques
Binatang-Ternak
 Hasil produksi yang lebih baik : daging, telur dan susu
 Perbaikan kesehatan binatang dan metode diagnosisnya
 Peningkatan resistensi, productivity, hardiness, dan efisiensi pakan
Lingkungan Hidup
 " Bioherbicides dan bioinsecticida” ramah lingkungan
 Konservasi tanah, air dan energi
 Bio-proses untuk produk kehutanan
 Pengelolaan limbah secara lebih baik
 Pengolahan lebih efisien.
Masyarakat
 Meningkatkan kertahanan pangan bagi penduduk yang semakin banyak
Recombinant DNA technology: genetically modified organism production
Sumber: http://www.britannica.com/EBchecked/media/122433/Genetically-modifiedorganisms-are-produced-using-scientific-methods-that-include ..... diunduh 30/6/2011
50
Kontroversi GMO
Keamanan
 Dampak potensial terhadap kesehatan manusia: allergens, transfer resistensi
antibiotic, efek-efek yang belum diketahui.
 Dampak potensial terhadap lingkungan: unintended transfer of transgenes through
cross-pollination, unknown effects on other organisms (e.g., soil microbes), and loss
of flora and fauna biodiversity
Akses dan Properti Intelektual
 Dominasi produksi pangan dunia oleh beberapa perusahaan
 Meningkatkan ketergantungan Negara berkembang kepada Negara industry maju
 Eksploitasi sumberdaya alam secara Biopiracy-foreign
Etika
 Pelanggaran nilai-nilai 50ntrinsic dari organism alamiah
 Tampering with nature by mixing genes among species
 Objections to consuming animal genes in plants and vice versa
 Stress bagi binatang
Some advocates favour sustainable agriculture as the only system which can be sustained
over the long-term. However, organic production methods, especially in transition, yield less than
their conventional counterparts and raise the same problems of sustaining populations globally.
Organic farming is the form of agriculture that relies on techniques such as crop rotation, green manure, compost
and biological pest control to maintain soil productivity and control pests on a farm. Organic farming excludes or
strictly limits the use of manufactured fertilizers, pesticides (which include herbicides, insecticides and fungicides),
plant growth regulators such as hormones, livestock antibiotics, food additives, and genetically modified organisms.
“Organic agriculture is a production system that sustains the health of soils, ecosystems and people. It relies on
ecological processes, biodiversity and cycles adapted to local conditions, rather than the use of inputs with adverse
effects. Organic agriculture combines tradition, innovation and science to benefit the shared environment and promote
fair relationships and a good quality of life for all involved..”
—International Federation of Organic Agriculture Movements
Productivitas dan Profitabilitas Pertanian Organik
Various studies find that versus conventional agriculture, organic crops yielded 91%, or 95100%, along with 50% lower expenditure on fertilizer and energy, and 97% less pesticides,
or 100% for corn and soybean, consuming less energy and zero pesticides. (Stanhill, G.
1990). The comparative productivity of organic agriculture. Agriculture, Ecosystems, and
Environment. 30(1-2):1-26).
The results were attributed to lower yields in average and good years but higher yields
during drought years. A 2007 study compiling research from 293 different comparisons into
a single study to assess the overall efficiency of the two agricultural systems has concluded
that
…organic methods could produce enough food on a global per capita basis to sustain
the current human population, and potentially an even larger population, without
increasing the agricultural land base.
51
(Perfecto et al.., in Renewable Agriculture and Food Systems (2007), 22: 86–108
Cambridge University Press: cited in New Scientist 13:46 12 July 2007)
Converted organic farms have lower pre-harvest yields than their conventional counterparts
in developed countries (92%) but higher than their low-intensity counterparts in developing
countries (132%). This is due to relatively lower adoption of fertilizers and pesticides in the
developing world compared to the intensive farming of the developed world. (Badgley, C. et
al. .Organic agriculture and the global food supply. Renewable Agriculture and Food Systems
(2007), 22: 86-108.
Organic farms withstand severe weather conditions better than conventional farms,
sometimes yielding 70-90% more than conventional farms during droughts.[42] Organic farms
are more profitable in the drier states of the United States, likely due to their superior
drought performance. Organic farms survive hurricane damage much better, retaining 20 to
40% more topsoil and smaller economic losses at highly significant levels than their
neighbors.
Contrary to widespread belief, organic farming can build up soil organic matter better than
conventional no-till farming, which suggests long-term yield benefits from organic farming.
An 18-year study of organic methods on nutrient-depleted soil, concluded that conventional
methods were superior for soil fertility and yield in a cold-temperate climate, arguing that
much of the benefits from organic farming are derived from imported materials which could
not be regarded as “self-sustaining”.[46]
Profitabilitas Pertanian Organik
(Lotter, D. (2003). “Organic Agriculture” (PDF). Journal of Sustainable Agriculture 21 (4).
http://donlotter.net/lotter_organicag.pdf.)
The decreased cost of synthetic fertilizer and pesticide inputs, along with the higher prices that consumers pay for
organic produce, contribute to increased profits. Organic farms have been consistently found to be as or more
profitable than conventional farms. Without the price premium, profitability is mixed. Organic production was more
profitable in Wisconsin, given price premiums.
Agroekosistem
(sumber: http://www.answers.com/topic/agroecosystem#ixzz1f2iWFTtJ)
An agroecosystem is the basic unit of study for an agroecologist, and is somewhat arbitrarily
defined as a spatially and functionally coherent unit of agricultural activity, and includes the living
and nonliving components involved in that unit as well as their interactions.
"Suatu agroekosistem dapat dilihat sebagai bagian dari ekosistem konvensional.
Bagian inti dari suatu agroekosistem adalah manusia dengan aktivitas pertaniannya.
Namun demikian, agroekosistem tidak terbatas pada kegiatan pertanian (misalnya
usahatani), melainkan juga termasuk kawasan yang dipengaruhi oleh kegiatan
pertanian ini, biasanya dengan perubahan kompleksitas spesies dan aliran energi, serta
untuk keseimbangan hara. Secara tradisional suatu agroekosistem, terutama yang
dikelola secara intensif, ditandai oleh adanya komposisi spesies yang lebih sederhana
dan aliran energi dan hara yang lebih sederhana daripada ekosistem alamiah.
52
Demikian juga, agroekosistem sering dikaitkan dengan masukan hara yang tinggi,
banyak yang ke luar dari system pertanian mengakibatkan munculnya eutrofikasi pada
ekosistem yang tidak secara langsung behubungan dengan pertanian ".
One of the major efforts of disciplines such as agroecology is to promote management styles
that blur the distinction between agroecosystems and "natural" ecosystems, both by decreasing the
impact of agriculture (increasing the biological and trophic complexity of the agricultural system as
well as decreasing the nutrient inputs/outflow) and by increasing awareness that "downstream"
effects extend agroecosystems beyond the boundaries of the farm. In the first case, polyculture or
buffer strips for wildlife habitat can restore some complexity to a cropping system, while organic
farming can reduce nutrient inputs. Efforts of the second type are most common at the watershed
scale. An example is the National Association of Conservation Districts' Lake Mendota Watershed
Project, which seeks to reduce runoff from the agricultural lands feeding into the lake with the aim
of reducing algal blooms. A model for the functionings of an agricultural system, with all inputs and
outputs. An ecosystem may be as small as a set of microbial interactions that take place on the
surface of roots, or as large as the globe. An agroecosystem may be at the level of the individual
plant-soil-microorganism system, at the level of crops or herds of domesticated animals, at the level
of farms or agricultural landscapes, or at the level of entire agricultural economies.
Ciri-ciri Agroekosistem
Agroekosistem berbeda dengan ekosistem alami dalam beberapa hal:
1. Energi yang mendorong semua ekosistem autotrophic, termasuk agroekosistem, baik
secara langsung maupun tidak langsung, berasal dari energi surya. Namun demikian,
input energi untuk agroekosistem tidak hanya mencakup energi alami (sinar matahari),
tetapi juga energi olahan (bahan bakar fosil) serta tenaga kerja manusia dan hewan.
2. Biodiversitas dalam agroekosistem umumnya dikurangi oleh adanya manajemen manusia
untuk menyalurkan sebanyak mungkin energi dan hara ke dalam system spesies
budidaya.
3. Evolusi adalah sebagian besar, melalui seleksi buatan, dimana sifat fenotipik yang
diinginkan secara komersial ditingkatkan melalui program pemuliaan dan rekayasa
genetika.
4. Agroekosistems biasanya dikaji dari berbagai Perspektif, termasuk Neraca dan Aliran
energi, pertukartan materi, Neraca hara, dan Dinamika populasi serta Komunitas.
Solar energy influences agroecosystem productivity directly by providing the energy for
photosynthesis and indirectly through heat energy that influences respiration, rates of water loss,
and the heat balance of plants and animals. Nutrient uptake from soil by crop plants or weeds is
primarily mediated by microbial processes. Some soil bacteria fix atmospheric nitrogen into forms
that plants can assimilate. Other organisms influence soil structure and the exchange of nutrients,
and still other microorganisms may excrete ammonia and other metabolic by-products that are
useful plant nutrients. There are many complex ways that microorganisms influence nutrient cycling
and uptake by plants. Some microorganisms are plant pathogens that reduce nutrient uptake in
diseased plants. Larger organisms may influence nutrient uptake indirectly by modifying soil
structure or directly by damaging plants.
Although agroecosystems may be greatly simplified compared to natural ecosystems, they
can still foster a rich array of population and community processes such as herbivory, predation,
parasitization, competition, and mutualism. Crop plants may compete among themselves or with
53
weeds for sunlight, soil nutrients, or water. Cattle overstocked in a pasture may compete for forage
and thereby change competitive interactions among pasture plants, resulting in selection for
unpalatable or even toxic plants. Indeed, one important goal of farming is to find the optimal
densities for crops and livestock.
Widespread use of synthetic chemical pesticides has bolstered farm production worldwide,
primarily by reducing or eliminating herbivorous insect pests. Traditional broad-spectrum pesticides
such as DDT, however, can have far-ranging impacts on agroecosystems. For instance, secondary
pest outbreaks associated with the use of many traditional pesticides are not uncommon due to the
elimination of natural enemies or resistance of pests to chemical control. Growers and pesticide
developers in temperate regions have begun to focus on alternative means of control. Pesticide
developers have begun producing selective pesticides, which are designed to target only pest
species and to spare natural enemies, leaving the rest of the agroecosystem community intact. Many
growers are now implementing integrated pest management programs that incorporate the new
breed of biorational chemicals with cultural and other types of controls.
ANALISIS AGROEKOSISTEM
Agroecosystem analysis is a thorough analysis of an agricultural environment which
considers aspects from ecology, sociology, economics, and politics with equal weight. There are
many aspects to consider; however, it is literally impossible to account for all of them. This is one of
the issues when trying to conduct an analysis of an agricultural environment. In the past, an
agroecosystem analysis approach might be used to determine the sustainability of an agricultural
system. It has become apparent, however, that the "sustainability" of the system depends heavily on
the definition of sustainability chosen by the observer. Therefore, agroecosystem analysis is used to
bring the richness of the true complexity of agricultural systems to an analysis to identify
reconfigurations of the system (or holon) that will best suit individual situations.
Agroecosystem analysis is a tool of the multidisciplinary subject known as Agroecology. Agroecology
and agroecosystem analysis are not the same as sustainable agriculture, though the use of
agroecosystem analysis may help a farming system ensure its viability. Agroecosystem analysis is not a
new practice, agriculturalists and farmers have been doing it since societies switched from hunting and
gathering (hunter-gatherer) for food to settling in one area. Every time a person involved in agriculture
evaluates their situation to identify methods to make the system function in a way that better suits
their interests, they are performing an agroecosystem analysis.
Analisis Agroecosystem dan Pertanian berkelanjutan
It is difficult to discuss these differences without the aid of an example. Consider the case of
a conventional apple farmer. This farmer may choose to change his farm to conform to the
standards of USDA approved organic agriculture because he felt motivated by social or moral norms
or the potential of increased profits or a host of other reasons. This farmer evaluated his situation
and reconfigured it to try to improve it. Some might look at this situation and conclude that the
apple farmer chose organic apple production because it is more sustainable for the environment.
But, what if a few years later the farmer finds that he is struggling to make a profit and decides to go
back to conventional agriculture? The farmer performed another agroecosystem analysis and arrived
at a reconfiguration that some might see as unsustainable. This example illustrates how
54
agroecosystem analysis is not required to lead a more environmentally sustainable form of
agriculture. Agroecosystem analysis might produce a reconfiguration that is more economically
sustainable or socially sustainable or politically sustainable for a farmer (or other actor). By
definition, however, agroecosystem analysis is not required to produce an environmentally
sustainable configuration for an agricultural system.
Pendekatan untuk Analisis
William L. Bland, from the University of Wisconsin–Madison, developed the idea of a farm as a
Holon (philosophy). This term, holon, was originally introduced by Arthur Koestler in 1966, in
which he referred to a holon as an entity in which it is a part by itself, a holon, while contributing
to a larger entity, which is also a holon. Bland develops this for an agricultural environment or
farm as, "The farm holon is both the whole in which smaller holons exists, and a part of larger
entities, themselves holons." This idea was expanded upon by Bland and Michael M. Bell
University of Wisconsin–Madison in their 2007 article "A holon approach to agroecology,"
because it is difficult to account for boundary and change when using a systems thinking
approach. One major difference between Koestler's holon and the holon idea developed for
agroecosystem analysis is that the latter can only be defined as a holon if it has intentionality.
The farm itself is a holon and within the farm holon, other holons exist. For example, a farm
animal, the farm family, and a farmworker can all be considered holons within the farm.
Additionally, the farm is considered a holon which is inpart connected to other holons such as the
county in which the farm resides, the bank from which the farmer borrowed money, or the grain
elevator where the farmer can sell goods. Things like the tractor or the barn are not holons because
they lack intentionality. When conducting an agroecosystem analysis, the analyst should approach
the farm as the farm itself and the "ecology of contexts" in which the farm and the farmer function.
A "context" is anything that might influence functioning of the farm and cause it to change.
According to Bland and Bell, examples of contexts include, "family, farm business, genetic heart
disease, and spiritual beliefs." These examples illustrate the breadth of contexts that could influence
why farmers do what they do. Bland concluded his model of a farm as a holon by stating, "A farm is
not sustainable (disintegrates) when it cannot find an overall configuration that is simultaneously
viable in all contexts."
Pertanyaan yang harus diperhatikan
There is no right or wrong way to evaluate an agroecosystem. It is important to identify all
actors in a holon before beginning the analysis. When an analyst accepts the task of analyzing the
agroecosystem, first and foremost, it must be approached as to incorporate all elements involved
and should derive questions that should be answered.
Pertanyaan-pertanyaan seperti:
 Apakah faktor-faktor pembatas (holons and contexts) menentukan konfigurasi
agroecosystem yang ada sekarang?
 Bagaimana mengkuantifikasikan keberl;anjutan suatu usahat pertanian (economi, social,
politis, ekologi dan/atau lainnya)?
 Bagaimana petani atau keluarga usahatani mempersepsikan suatu agroecosystem?
 Apa saja yang dilakukan petani saat ini, dan bagaimana praktek-praktek tersebut
mempengaruhi viabilitas agroecosystem?
55



Dapatkan petani melestarikan kesejahteraannya dengan praktek-praktek yang ada sekarang?
Apakah nilai-nilai yang dianut oleh petani dari darimana asalnya nilai-nilai tersebut?
Apakah petani akan mempertimbangkan alternatif konfigurasi usahataninya?
Manajemen Agroekosistem
Organic Agro-Ecosystem Management from Prototyped Organic Farmer Learning
Processes. Yuppayao Tokeeree, Sunantha Laowansiri and Sopit Vetayasuporn. 2010. The
Social Sciences, 2010 , Volume: 5 , Issue: 6, Page 532-537.
Penelitian ini dilakukan untuk mempelajari manajemen agroekosistem organic dan mensintesis
proses pembelajaran yang dilakukan oleh petani organic Mr. Kampan Laowongsri. Mr. Kampan
adalah prototype petani organic yang menerapkan system pertanian terpadu di propinsi
Mahasarakarm. Sistem pertanian terpadu ini sesuai dengan kaidah-kaidah mutual-manajemen
antara sumberdaya fisik dan sumberdaya buiologis serta system pemanfataan limbahnya.
Limbah pertanian dirombak dan diolah menjadi material yang bermanfaat dan digunakan
dalam proses pertanian.
Hasil-hasil penelitian ini menunjukkan bahwa keberhasilan system pertanian organic terpadu
ini berpangkal dari proses pembelajaran sendiri petani, prinsip kearifan local, dan pengalaman
yang telah dilalui dari generasi ke generasi, percobaan-percobaan, saran pemerintah dan suasta,
diskusi komunitas dan informasi-informasi lainnya. Sistem pertanian organic terpadu dari Mr.
Kampan ini bukan hanya bertumpu pada keragaan usahatani, tetapi juga mewujudkan
kelestarian, kelayakan ekonomi, kesejahteraan petani, keramahan lingkungan dan hasil-hasil
opertanian yang aman dikonsumsi. Kecuali itu, kelebihan hasil-hasil pertanian dari konsumsi
keluarga dapat dijual dan menghasilkan income bagi keluarganya.
PROTOTIPE SISTEM PENGELOLAAN AGROEKOSISTEM ORGANIK
Pertanian organik adalah sistem produksi pertanian bahan pangan dan serat yang
berkelanjutan secara sosial, ekonomi dan lingkungan. Hal ini berkonsentrasi pada pemupukan
tanah dan memperhatikan kemampuan alami tanaman, hewan dan agro - ekosistem. Pertanian
organik mengurangi faktor produksi eksternal dan meninggalkan penggunaan bahan kimia
sintetik. Sistem ii menekankan pada penggunaan limbah tanaman, rabuk, tanaman legume,
pupuk hijau dan bahan organik lainnya, untuk mendaur-ulangkan hara dan energi dalam
system pertanian. Pertanian ini mencakup upaya kelestarian lingkungan dengan menjaga
keseimbangan alam dan keanekaragaman hayati, sehingga manajemen agroekosistem organik
mirip dengan alam dan sesuai dengan kearifan lokal. Oleh karena itu, pertanian organik
merupakan proses pertanian yang mengandalkan jasa-jasa alam, dengan jalan menggunakan
proses biologis untuk meningkatkan produksi dan mencegah gangguan hama, dan mengikuti
sirkulasi sumberdaya yang digunakan dalam pertanian untuk manfaat maksimal . Oleh karena
itu , prinsip pertanian organik akan sesuai dengan kondisi lokal dalam hal ekonomi, socialmasyarakat, cuaca dan budaya . Manajemen agroekosistem organik merupakan faktor penting
yang mengarah kepada pengembangan pertanian berkelanjutan.
Regarding to this management, farmers must be diligent and patient in cultivation that there
are methods as the followings: soil fertile management by main using of organic matters, circulating
plants cultivation emphasizing on local plants, no usage of agricultural machines to maintain and
curing soil structural properties, no usage of pesticides, herbicides and other chemicals and soil-
56
covering plants cultivation instead of chemicals usage. Besides, the land management is another
factor that is very simportant to be the base of agro-ecosystem built. It regards with various plants
cultivation, internal and inter-relative areas organism management and farm areas allocation that
are necessary to have a good plan for creating a new agro-ecosystem of organic farms. These
managements actually are the ancient agriculture in local communities of Asian countries. The
mutual conditions in food chain and food web interaction including energy exchange have created
the ecological sustainability for instances, resource units in farm production, rice cultivation, fish
farming and horticultural cultivation can be used to circulate and mutual support in the dimension of
resource and energy transferring. Mahasarakarm, a province in Thailand, supports activities of
organic farming to farmers.
Farmers have started to cultivate plants and domesticate animals with creating the agroecosystem balance in farms. Many of them have succeeded in the organic farming management that
helps to generate organic or green products creating health benefits to farmers and consumers as
well as income to farmers in long term operation. The organic farmer has worked on the basis of
agro-ecosystem intention by allocating relevant resources and creating the organic agro-ecosystem
in his farm appropriately with local conditions as well as emphasizing on the integrated management
comprising the items as follows.
PENGELOLAAN LAHAN: The farmer land has been allocated accordingly with the new
agricultural theory. The theory has defined the land proportion of water source: rice field:
horticultural field: accommodation as 30: 30: 30: 10, respectively. His farm land proportion was 24.8:
19.7: 45.8: 9.7 due to the performance and adjustment following the suitability of local ecological
geography. When in-depth studying of land allocation, his land has been separated into 9 sub-areas
i.e., rice field, mixed horticultural and vegetable field, circulating seasonal vegetable field, asparagus
field, herbal field, rice filed and pool edges, water source, animal domesticating area and rice straw
group. The highest amount land is the water source area for solving the lack of water in summer
season. The rice field edge also consumes a large area by constructing the big size edges to protect
water drainage from outside lands which contaminate chemicals and prevent flood. Besides, the
edges can be used to cultivate plants especially perennial trees.
PENGELOLAAN TANAH: The prototyped farmer has fertilized to improve the soil quality by
using manures, green manures from vetch plants, fermented manure, biological fermented water,
plowing without rice cob burning and reducing soil nutrients by low waste harvesting of products.
Furthermore, there are the cultivation of circulating plants for maintaining nutrients balance, the
conservation of soil benthos and the protection of soil erosion by cultivating plants on rice filed and
pool edges and soil covered plants.
PENGELOLAAN AIR: In northeast Thailand, most farmers have faced the drought problem
and there is no sufficient water for cultivating plants, especially in summer season. Therefore, the
prototyped farmer constructed the pools for water using sufficiently in throughout year. He has
allocated the land for water resource about 24.8% that there are 3 pools total containing 10,453 m 3.
In addition, he has managed water resource with water supply system by installing small water
pumps, PVC pipe lining to cover farm area and installing water sprinkles having specific valve
breaker. The breaker will be opened when watering plants at desired time and watering will be
controlled suitably to disperse water and protect evaporation. Most sprinkles can easily move for
comfortably water supply management and after harvesting they can move out for soil plowing.
57
PENGELOLAAN TANAMAN DAN TERNAK: The prototyped farmer emphasize on biodiversity
and mutualism condition among organisms in his farm. There were 139 species and 56 families of
plants i.e., 15 species of shrub, 45 species of perennial plant and 79 species of biennial plant. Each
species taken to cultivate in the farm had been selected by mixing local wisdom principles with
regards to benefits and science bases.
The plants were tested in the experimental land until receiving the appropriate species that
are mutual basis in the organic agro-ecosystem. Besides, there is the cultivation of circulating
seasonal plants accompany with vetch plants in the same field creating good products due to
nutrients balance as well as nitrogen cycle.
The main characteristic of this farm is the neatly rice cultivation. He has cultivated by using a
rice sprout in one hole that one rai (1,600 m3) uses only 1 kg of seeds. The selected seeds have been
cultured for 7 days that a rice sprout has the length about 10-15 cm. Then the sprouts have been
transferred to cultivate in the prepared rice filed having sludge characteristic. They have been pulled
out by using a spoon to scoop for maintaining the seed left. After that they are transferred to
cultivate as soft sticking their seed roots to the field because the sprouts are still young.
In the first stage, watering them is like vegetable watering that soil is just soaked until the
sprouts were split. In addition, it is necessary to release water out until the appropriate water level
because if there is more water in the filed crabs will destroy rice but less water weeds will grow
which is wasting time to get rid of them. Therefore, farmers should pay attention in their cultivation
and emphasize on the integrated farming system by no mono-crop cultivation and biodiversity
consideration. The prototyped organic farmer gave the reasons for organic agro-ecosystem as the
followings.
The organic farming emphasizes on cultivation for consumption and income circulation all
year round. Due to the differences of harvesting period the cultivating plants can be circulated to
give production throughout a year. Then, it can help to support farmers in terms of consumption and
commerce throughout a year. It helps to protect outbreaks of diseases and pests because pests
cannot destroy the area of integrated plants in a wide range. Most cultivating plants are local species
that can be found easily. These species are easy in curing and appropriate with annual water
amount.
Farmers will cultivate herbs for getting rid of pests throughout a year without using from
other chemicals. These help to their self-assistance that farmers will use their resources in a
sufficient way. Regarding to domesticating animals, there are 7 types i.e., cow, chicken, duck, cricket,
frog, fish and pig. Most animals are local species that are tolerant to environmental conditions and
easy in domesticating with giving high products. These create income circulation throughout a year.
Additionally, these animals help to circulate nutrients and be a source of organic manure. Other
natural animals such as earthworm, millipede, ground lizard, predator insect and so on are beneficial
for organic decomposition and controlling pests in the fields.
PENGELOLAAN HAMA
From the investigation, there were 52 species and 43 families of pests that were 38.46% of
pest insects, 42.31% of predator insects, 3.85% of parasites and 15.38% of cross-pollination insects.
These proportions show that the beneficial pespts found in the organic farm were higher than the
pest insects. There are 3 methods of pest control and management i.e., using wood vinegar, using
biological fermented water and cultivating pest controlling plants.
Wood vinegar is produced from charcoal burning and the biological fermented water is
generated from the fermentation of herbs in the field. These herbal plants are in local forest and
have been using since the past such as tuba root (Derris sp.), Ebony, Nim, Sarcostemma acidum Voigt
58
(Leafless medicinal tree), Stemona sp., Cassia fistula L., Jatropha curcas L. and so on. For using, these
plants must be dissolved in water and then sprayed into the cultivating fields as suitably with each
type of plants. Regarding with the cultivation for pests controlling, the prototyped organic farmer
has cultivated various types of plants, integrated plants, circulating seasonal plants and insect
attracting-expelling plants such as marigold, sunflower, sympodium and so on. These cultivations
have created the biodiversities of species and disturbed the pests that cannot select the specific
plant for living and eating as usual. Hence, they are an alternative choice to control pests naturally
instead of using chemicals, including help to reduce risks of farmers.
PENGELOLAAN LIMBAH.
The organic agro-ecosystem supports the waste management. The prototype organic farmer
has used the occurred wastes to recycle for using in the production processes. The study found that
the production and household wastes such as animal manures, vegetable refuses, leaves and solid
wastes have been totally recycled. If there are the decomposing wastes such as food refuses,
vegetable refuses and leaves he uses most of them to produce the soil fertilizer and some of them to
produce the biological fermented water. The fresh vegetable refuses have been used for feeding
cricket, chicken and goose. For the recycled wastes such as plastics, paper, glasses and bottles, he
has used them as recycling or collecting for sale. The management of organic agro-ecosystem
components can introduce the linkage among the components. These management characteristics
are duplicated from the nature for producing foods and agricultural products as environmentally
friendly system. The organic agro-ecosystem management of Mr. Kapan Laowongsri is a very good
case study because he has created the organic farming system as mutual consideration under the
limitations of area, soil, water and air to be appropriate with plants and animals. His management
has cooperated between physical and biological resources by emphasizing on soil fertility, water
source, weather controlling with perennial plants, plant species selection for mutual conditions and
so on. This relationship is from the selection and creation of the prototyped organic farmer with
intention and harmonious mixing the new interdisciplinary knowledge and the local wisdom.
Each resource has then presented its roles and has linked with the others in the productive
ways. Plants and animals in the fields have been arranged to use the physical resources as maximum
beneficiaries. His management has helped to circulate nutrients and resources, allocate the selected
plants as suitably, fertilize soil and maximize recycled wastes use in his organic farm. These are the
interdisciplinary organization creating the knowledge of organic agro-ecosystem. His self-learning
processes have crated the understandings of the organic agro-ecosystem that he began from
analyzing the ecosystem components in his farm by appropriately adjusting resource proportion,
worker and investment. After that he established the suitable methods accounting with worker and
budget in his family and accompanied with learning the organic agro-ecosystem processes. He has
been always learning from agricultural study trips, farmer talks and other agricultural academic
sources. Then he has used gained knowledge to experiment, Trial and error test and adjust methods
to suit with his farm conditions including resource, worker and budget until receiving the
appropriate performances of his farm. These performances have generated good products
sufficiently for consumption and incomes for circulating in his family and farm.
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Model pengelolaan agroekosistem organic dari hasil proses pembelajaran petani organic (Sumber:
http://www.medwelljournals.com/fulltext/?doi=sscience.2010.532.537….. diunduh 2/7/2011)
Perbaikan praktek budidaya dan sumberdaya yang ada sat ini dengan memasukkan
beberapa tipe pupuk organic tampaknya menjadi metode yang opaling menjanjikan untuk berhasil
pada saat ini. Beberapa poraktek untuk memperbaiki kesuburan tanah dijelaskan berikut ini.
KONSERVASI TANAH
Metode konservasi tanah harus dilakukan untuk dapat memperbaikii kesuburan tanah. Soils
of hills are lost through detrimental agronomic practices such as slicing terrace risers every year,
excessive tillage and hoeing in the rainy season, and severe grazing pressure on pasture and forest
lands. In order to first check mass soil erosion, improvements to the management of grazing land
and degraded forest land are essential. Use of minimum tillage methods, and preventing the practice
of slicing tall bariland risers should be adopted to reduce further soil losses. This last practice should
be restricted to those areas where soil loss is not a problem, for example flat khetland as discussed
above.
Perbaikan Produktivitas Lahan
The major reason for declining soil fertility is the need to use the land more intensively
because of increasing human population, coupled with a reduction in manure production, so that
60
nutrients extracted by food crops are not adequately replaced. This is the result of a reduction in
animal populations in some areas, but is mostly the result of depletion of the animal feed resources
from the forest and grass lands, which means that livestock are not realising their full potential the
year round.
Productivity of open grassland and forest in the mid-hills is estimated to be able to support
only 0.54 and 0.31 livestock units/ha respectively, whereas the present stocking rate is about nine to
thirteen times greater than the carrying capacity (Wyatt-Smith, 1982). Therefore, urgent attention
must be given to resolving this situation by managing the forest resources properly. Productivity
from the forest could be increased by giving priority to fodder tree planting, along with the
introduction of improved varieties of grasses and legumes between the trees under silvipastoral
management systems.
Perbaikan Sistem Manajemen Ternak
Large herds or flocks of animals of sub-optimal productivity are not worth much in terms of
overall agricultural production, and poor management systems do not help to increase the quantity
of animal products. Since 46% of manure is lost in grazing away from the farm, it has been estimated
that even if the animal numbers in the hills of Nepal were halved, manure production would remain
almost what it is at present, provided that it was collected and utilized properly. Stall-feeding could
result in a doubling of the amount of dung collected per animal at present.
Animal populations already overburden the hill farmer, and it is essential to consider
complete stall-feeding in order to use the available feed effectively and maximise manure
production. The wastage of valuable urine can be prevented and utilized by improving drainage and
constructing a store pit at the animal shed. Losses of manure due to rain and sun could be minimised
by providing some kind of simple shelter over the compost heap/pit.
Similarly, animal production could be improved by the timely supply of feed and water,
without wastage. Straw as a livestock feed can be improved in quality by treatment with urea, and
by the practice of ensiling or otherwise preserving the summer surplus of grass and agricultural crop
by-products. These could then be consumed during the food scarcity period of winter. Trials to this
effect are being carried out under the Fodder Thrust programme previously described.
Perbaikan Budidaya Tanaman
In order to supply food grain for a steadily increasing human population from a fixed or
limited land resource, improvements to existing farming practices are inevitable. From the soil
conservation and fertility standpoint, intercropping of grain legumes within the major cropping
systems should be encouraged whenever possible. Similarly, planting grasses and legumes on
terrace risers, on farm boundaries and on irrigation bunds should be practised more widely. Legume
crops such as cowpea, and crops such as oats and berseem can be grown after the rice is harvested
using zero tillage, with broadcasted seed while the ground is still moist. Such practices would
provide substantial amounts of forage with a minimum of labour, and render the soil more fertile.
Improved crop varieties will give more return over local varieties, particularly where intensive
cultivation, and irrigation facilities, or other input supplies are available. However, to achieve this in
the hills, government subsidies in addition to technical information may be necessary.
Perbaikan Simpanan dan Aplikasi Pupuk / Rabuk Organik
Because of a present lack of awareness of correct preparation methods, manure is often
mixed with farm and forest waste in a heap, does not decompose properly, and so is inferior in
quality. To alleviate such problems, the pit method of composting should be adopted, and if possible
61
a “starter” such as dung slurry, should be applied to assist proper decomposition. However, possible
socio-economic constraints need to be evaluated before recommending these changes to farmers
on a wide scale, because of the implied extra labour requirements involved.
Penggunaan Pupuk Alternatif
Input tambahan (pupuk dan teknologi) diperlukan untuk meningkatkan produktivitas
tanaman. Pada saat suplai pupuk organik tidak cukup, penggunaan pupuk kimia harus
dipertimbangkan. Meskipun mahal, dan tidak dapat diandalkan pasokannya di daerah pelosok
pedesaan, penggunaan pupuk kimia dapat melengkapi aplikasi kompos atau pupuk kandang.
Hati-hati menggunakannya, sebaiknya dalam kombinasi dengan pupuk organik, supaya dapat
meningkatkan hasil tanaman tanpa menyebabkan kerusakan kualitas tanah. Penggunaan
pupuk hayati, air banjir, dan inokulasi Rhizobium yang sesuai pada benih legum, juga dapat
membantu untuk mengurangi efek kelangkaan pasokan pupuk organik.
Kompos dan Pupuk Hijau
The present trend of only exploiting green manuring plants should be changed to one of
developing their production on a sustainable basis. More than twenty species have been identified
that have some sort of role as green manure, but very few are being consciously propagated by
farmers. Research into the most suitable species for assessing their quality, and the feasibility of
increasing their production should be given high priority.
Penguatan Kelembagaan dan Pemberdayaan SDM
The limited number of scientists to investigate problems of soil fertility, and also suffers
from insufficient infrastructural and technical laboratory facilities at present. This is hampering the
development of improved soil conservation and fertility maintenance methods, through lack of
technical information and analytical support services.
AKUAKULTUR
Budidaya perairan (akuakultur) merupakan bentuk BUDIDAYA berbagai hewan atau
tumbuhan perairan yang menggunakan air sebagai komponen pokoknya. Kegiatan-kegiatan yang
umum termasuk di dalamnya adalah budidaya ikan, budidaya udang, budidaya tiram, serat budidaya
rumput laut (alga). Dengan batasan di atas, sebenarnya cakupan budidaya perairan sangat luas
namun penguasaan teknologi membatasi komoditi tertentu yang dapat diterapkan. Budidaya
perairan adalah bentuk perikanan budidaya, untuk dipertentangkan dengan perikanan tangkap. Di
Indonesia, budidaya perairan dilakukan melalui berbagai sarana. Kegiatan budidaya yang paling
umum dilakukan di kolam/empang, tambak, tangki, karamba, serta karamba apung.
(http://id.wikipedia.org/wiki/Budidaya_perairan).
62
Coastal aquaculture and the environment
((Guidelines for the promotion of environmental management of coastal aquaculture development (based
on a review of selected experiences and concepts). FAO Fisheries Technical Paper. No. 328. Rome, FAO.
1992. 122 p. )
Benefits of Coastal aquaculture
Generally, the socio-economic benefits arising from aquaculture expansion include the provision of
food, contributing to improved nutrition and health, the generation of income and employment, the
diversification of primary production, and, increasingly important for developing countries, foreign
exchange earnings through export of high-value products (UNDP/Norway/FAO, 1987; Schmidt,
1982).
1. Aquaculture is also being promoted for its potential to compensate for the low growth rate of
capture fisheries. Stocking and release of hatchery-reared organisms into inland and coastal
waters support culture-based fisheries (Larkin, 1991).
2. Sustainable development of aquaculture can contribute to the prevention and control of
aquatic pollution since it relies essentially on good-quality water resources.
3. Culture of molluscs and seaweeds may in certain cases counteract processes of nutrient and
organic enrichment in eutrophic waters. Conversely, productivity of oligotrophic waters may
be enhanced due to the nutrient and organic wastes released from aquaculture farms.
4. Aquaculture can contribute to rehabilitation of rural areas through re-use of degraded land.
Key areas of ecological concern : Nutrient and organic enrichment
Many aquaculture operations invariably result in the release of metabolic waste products (faeces,
pseudo-faeces and excreta) and uneaten food into the aquatic environment. In general, the recipient for
soluble waste is the water column and the recipient for the organic waste is the sediment.
The release of soluble inorganic nutrients (nitrogen and phosphorus) has the potential to cause
nutrient enrichment (hypernutrification) possibly followed by eutrophication (increase of primary
production) of a waterbody. Related changes in phytoplankton ecology may result in algal blooms, which
can be harmful to wild and farmed organisms. However, there is no evidence that algal blooms have been
caused by coastal aquaculture.
The largest proportion of solid wastes released, which is predominantly organic carbon and
nitrogen, settles to the seabed in the immediate vicinity of the farm. Organic enrichment of the benthic
ecosystem may result in increased oxygen consumption by the sediment and formation of anoxic
sediments, with, in extreme cases, outgassing of carbon dioxide, methane and hydrogen sulphide;
enhanced remineralization of organic nitrogen and reduction in macrofauna biomass, abundance and
species composition.
There is evidence of very localized effects of reduced concentrations of dissolved oxygen in
bottom and surface waters close to farm sites which are due to the considerable biochemical oxygen
demand of released organic wastes and the respiratory demands of the cultured stock.
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Coastal zones for shrimp culture. I. Intertidal Zone; Mangrove virgin forest (A); Secondary forest (B). II.
Supratidal Zone: Rice field (C); Coconut plantation (D). (from Poernomo, 1990). Sumber:
http://www.fao.org/docrep/T0697E/t0697e04.htm
Tambak MERUPAKAN kolam buatan, biasanya di daerah pantai, yang diisi air dan
dimanfaatkan sebagai sarana budidaya perairan (akuakultur). Hewan yang dibudidayakan adalah
hewan air, terutama ikan, udang, serta kerang. Penyebutan "tambak" ini biasanya dihubungkan
dengan air payau atau air laut. Kolam yang berisi air tawar biasanya disebut kolam saja atau empang.
Kondisi dasar tambak merupakan suatu keadaan fisik dasar tambak beserta proses yang terjadi
didalamnya baik yang menyangkut biologi, kimia, fisika maupun ekologi yang secara langsung
maupun tidak langsung ikut berpengaruh pada kehidupan udang maupun organisme lainnya dalam
suatu keterkaitan ekosistem perairan tambak. Parameter ini dapat dijadikan sebagai salah satu tolok
ukur kualitas perairan tambak dengan dasar pemikiran sebagai berikut:
“Dasar tambak” merupakan ruang gerak dan tempat hidup bagi udang dan organisme
lainnya dalam kondisi normal seperti habitat alaminya, sehingga kondisi dasar tambak akan
mempengaruhi tingkat keamanan dan kenyamanan bagi udang maupun organisme lainnya di dalam
perairan tersebut. Dasar tambak juga merupakan tempat akumulasi kotoran tambak baik yang
berasal dari treatment budidaya maupun proses metabolisme yang dilakukan oleh organisme yang
64
hidup di perairan tambak tersebut. Dasar tambak merupakan suatu area di dalam tambak yang
membentuk suatu sub komunitas tersendiri yang bersifat benthic di dalam tambak dan
keberadaannya mempunyai korelasi yang erat dengan ekosistem perairan tambak.
Pada dasar tambak terjadi proses-proses biologi, kimia, fisika dan ekologi yang sangat
tergantung pada kestabilan ekosistem perairan. Pada kondisi tertentu, dasar tambak dapat bersifat
an aerob karena tidak terjadinya proses oksidasi sehingga dapat membahayakan bagi kondisi dan
kualitas udang di dalam tambak. Kondisi dasar tambak mempunyai keterkaitan secara langsung
dengan kondisi dan kualitas udang serta kualitas perairan tambak, yaitu jika perairan tambak berada
pada keseimbangan ekosistem dan bersifat stabil serta kondisi dan kualitas udang bagus maka
kondisi dasar tambak akan terjaga dengan sendirinya. Salah satu faktor yang juga ikut menentukan
kondisi dasar tambak adalah penempatan posisi kincir air yang dioperasikan pada saat kegiatan
budidaya berlangsung. Posisi kincir yang sesuai dan dapat mengarahkan kotoran dasar tambak ke
arah sentral pembuangan dapat meminimalkan terjadinya penyebaran akumulasi kotoran tersebut
di dasar tambak, sehingga pada saat dilakukan pembuangan air tambak kotoran tersebut dapat ikut
terbawa.
Pada dasarnya setiap petakan tambak yang sedang dioperasikan selalu dijumpai adanya
kotoran dan hal yang perlu diperhatikan adalah tingkat keberadaan dan tingkat penyebarannya di
dasar tambak dibandingkan dengan tolok ukur dari hasil pengamatan terhadap kondisi dan kualitas
udang serta kualitas perairan tambak. Beberapa faktor penyebab yang dapat mengakibatkan
terjadinya akumulasi kotoran di dasar tambak adalah (http://id.wikipedia.org/wiki/Tambak_Ikan):
1. Desain dan kontruksi dasar tambak yang tidak dirancang dengan tingkat kesesuaian
terkonsentrasinya kotoran ke arah sentral pembuangan, sehingga menyebabkan
kotoran di dasar tambak tersebut menyebar di beberapa titik konsentrasi.
2. Penempatan posisi kincir air yang kurang tepat, sehingga tidak dapat mengarahkan
kotoran tersebut ke arah sentral pembuangan.
3. Program pakan yang over feeding jika dibandingkan dengan tingkat kebutuhan udang.
Sisa pakan yang berlebihan tersebut tidak terkonsumsi oleh udang dan membusuk
serta terakumulasi di dasar tambak menjadi kotoran.
4. Teknik pemberian pakan yang tidak merata ke seluruh area pakan di dalam petakan
tambak, sehingga pakan terakumulasi di satu titik dan tidak terkonsumsi merata
sehingga membusuk di dasar tambak.
5. Tingkat populasi udang di dalam tambak. Pada tambak dengan populasi udang yang
relatif padat, kondisi dasar tambak akan relatif bersih karena kotoran di dasar tambak
akan terdorong dengan sendirinya ke sentral pembuangan yang diakibatkan oleh
aktifitas udang di dasar tambak.
6. Kurangnya pengecekkan dasar tambak dengan melakukan penyelaman secara berkala.
7. Kurangnya intensitas dan frekuensi sirkulasi air yang dapat mendorong kotoran dasar
tambak ke arah sentral pembuangan.
65
Berkembangnya system budidaya perairan (akua-kultur) dianggap sebagai era “Revolusi
Biru” karena mendatangkan berbagai manfaat bagi kehidupan manusia dan ramah
lingkungan
(Jeremy Elton Jacquot, Technology / Clean Technology, June 19, 2007 )
Jeffrey Sachs, the director of the Earth Institute at Columbia University and world-renowned
anti-poverty crusader, has turned his prodigious attention to an issue dear to many of us in the
TreeHugger community: environmental sustainability.
Aquaculture, could support rising consumption of seafood while reducing anthropogenic
pressures on oceanic ecosystems. This "Blue Revolution" has come at a critical time because,
as he put it:
"Between 1950 and today the total landed catch from open- and inland-sea fishing almost
quintupled, from around 20 million to about 95 million metric tons. Both higher demand from
rising world incomes and higher supply from more powerful fishing vessels contributed to the
surge. So, too, did large and misguided subsidies to fishing fleets, reflecting the political power
of geographically concentrated fishing communities and industries. The world put itself on a
course to gut ocean ecosystems, with devastating consequences."
Sumber: http://www.treehugger.com/clean-technology/discussing-the-merits-of-aquaculture.html
66
Sumber: http://www.feedingminds.org/fmfh/fisheries-aquaculture/wonders-of-the-oceans/from-thesea-to-your-plate/lesson-9-farming-fish/en/
Sistem akuakultur terpadu (budidaya udang, ikan, dan mangrove) di
Kenya
Photographer: Max Troell . Sumber:
http://www.azote.se/index.asp?q=vattenbruk&id=14138&p=40&lang=eng
67
DAFTAR PUSTAKA
Agro-ecosystem Health Project. 1996. Agroecosystem health. University of Guelph, Guelph, Canada.
Ahl, V. dan T.F.H.Allen. 1996. Hierarchy Theory: A Vision, Vocabulary, and Epistemology. Columbia
University Press, New York.
Allen, T. F. H. dan T.B.Starr. 1982. Hierarchy: Perspectives for Ecological Complexity. University of
Chicago Press, Chicago.
Allen, T. F. H. Tainter, J. A. Pires, J. C. dan T. W. Hoekstra. 2001. Dragnet Ecology-- "Just the Facts
Ma'am":The Privilege of Science in a Postmodern World. BioScience 51, 475-485.
Aristotle. 1987. A New Aristotle Reader. Edited by J. L. Ackrill. Princeton University, Princeton, NJ.
Bakhtin, M. 1981. The Dialogic Imagination: Four Essays. University of Texas, Austin, TX.
Begon M, Harper JL, Townsend CR. 1990. Ecology: Individuals, Populations and Communities (2nd
ed). Blackwell Science, London, 1068p.
Bland, B. 2005. A framework for enquiry into agricultural systems.
Bland, W.L. and Bell, M.M. 2007. A holon approach to agroecology International Journal of
Agricultural Sustainability 5(4), 280-294.
Cai Y. and Smit B. 1994. Sustainability in agriculture: A general review. Agriculture, ecosystems and
environment 49:299–307.
Checkland, P. dan J. Scholes. 1999. Soft Systems Methodology in Action, Including Soft Systems
Methodology: A 30-Year Retrospective. Wiley, New York.
Conway, G. 1990. Concepts. Ch 2. In Agroecosystem analysis for research and concepts. Winrock Int.
Inst. for Agriculture. Morrilton, AK.
Cronon, W. 1992. A Place for Stories: Nature, History and Narrative. Journal of American History 78,
1347-1376.
Crosson P. 1992. Sustainable agriculture. Resources 106:143–156.
Elske van de Fliert dan Ann R. Braun. 1999. Farmer Field School for Integrated Crop Management of
Sweetpotato. Field guides and Technical Manual. Bogor, Indonesia: International Potato
Center. ISBN 92-9060-216-3. http://www.eseap.cipotato.org/MF-ESEAP/Abstract/FFS-ICMSP-Ind.htm
Flint M.L. dan P.Gouveia. 2001. IPM in Practice: Principles and Methods of Integrated Pest
Management. University of California, 296p.
Francis, C. 2005. Cobweb polygons (spider diagrams) for visual display of sustainability
Gell-Mann, M. 1994. The Quark and the Jaguar. W. H. Freeman, New York, NY.
Gell-Mann, M. 1995. Complex Adaptive Systems. In: H. Morowitz & J. Singer (eds.) The Mind, the
Brain, and Complex Adaptive Systems, pp. 11–23. Addison-Wesley, New York, NY.
Gliessman, S. 2004. Chapter 2, Agroecology and agroecosystems. In D. Rickerl and C. Francis, (ed.)
Agroecosystems Analysis. American Society of Agronomy, Madison, WI.
Gliessman, S. R. 2004. Agroecology and Agroecosystems. In: D. Rickerl & C. Francis (eds.)
Agroecosystem Analysis, pp. 19–29. American Society of Agronomy, Madison, WI.
Huffaker C.B. dan A.P. Cutierrez. 1999. Ecological Entomology. John Wiley & Sons, New York, 756p.
ILRI (International Livestock Research Institute). 1998. Enhanced human well-being through
improved livestock and natural resource management in the East African Highlands.
Research Proposal submitted to IDRC. ILRI, Nairobi, Kenya.
Jahn G.C. and J.W.Beardsley. 2000. Interactions of ants (Hymenoptera: Formicidae) and mealybugs
(Homoptera: Psedococcidae) on pineapple. Proc. Hawaiian Entomol. 34, 181-185.
68
Koestler, A. 1967. The Ghost in the Machine. London: Hutchinson. 1990 reprint edition, Penguin
Group. ISBN 0-14-019192-5.
Krebs, CJ. 1978. Ecology: the Experimental Analysis of Distribution and Abundance (2nd ed.). Harper
& Row, New York, 678p.
Loucks, Orie. 1977. "Emergence of Research on Agro-Ecosystems". Annual Review of Ecology and
Systematics
8:
173–192.
http://arjournals.annualreviews.org/
doi/pdf/10.1146/
annurev.es.08.110177.001133?cookieSet=1.
McNeely, J. and Scherr, S.; 2003. Ecoagriculture: strategies to feed the world and save wild
biodiversity. Island Press, London.
Michael, P. 1994. Metode Ekologi untuk Penyelidikan Lapangan dan Laboratorium. UI Press : Jakarta.
Peart, R. M. dan W.D. Shoup. 2004. Agricultural Systems Management: Optimizing Efficiency and
Performance. Marcel Dekker, New York.
Rosen, R. 1991. Life Itself: A Comprehensive Inquiry into the Nature, Origin, and Foundation of Life.
Columbia University Press, New York.
SCC (Science Council of Canada). 1992. Sustainable agriculture: The research challenge. SCC, Ottawa,
Canada.
Schowalter T.D. 1996. Insect Ecology: An Ecosystem Approach. Academic press, San Diego, 483p.
Smit B. and Brklacich M. 1989. Sustainable development and analysis of rural systems. Journal of
rural studies 5:405–414.
Smit B. and Smithers J. 1994a. Sustainable agriculture: Interpretations, analyses and prospects.
Canadian journal of regional science 16(3):499–524.
Smit B. and Smithers J. 1994b. Sustainable agriculture and agro-ecosystem health. In: Nielsen N.O.
(ed), Agroecosystem health. Proceedings of an international workshop. University of Guelph,
Guelph, Canada. pp. 31–38.
Smit B., Waltner-Toews D., Rapport D., Wall E., Wichert G., Gwyn E. and Wandel J. 1998. Agroecosystem health: Analysis and assessment. University of Guelph, Guelph, Canada.
Spedding, C. R. W. 1988. An Introduction to Agricultural Systems. Elsevier Applied Science, New
York.
Speight M.R., M.D.Hunter dan A.D. Watt. 1999. Ecology of Insects: Concepts and Applications.
Blackwell Science, London, 350p.
Vayda, A. P. 1986. Holism and Individualism in Ecological Anthropology. Reviews in Anthropology
13, 295-313.
Waltner-Toews D. 1994. Ecosystem health: A framework for implementing sustainability in
agriculture. In: Nielsen N.O. (ed), Agroecosystem health. Proceedings of an international
workshop. University of Guelph, Guelph, Canada. pp. 8–23.
Wojtkowski, P.A. 2008. Agroecological Economics: Sustainability and Biodiversity. Elsevier Publishing,
NY.