KONSEP DASAR AGROEKOSISTEM
Bahan kajian MK. Manajemen Agroekosistem FPUB Maret 2010
Diabstraksikan oleh
Prof Dr Ir Soemarno MS
Dosen Jur Tanah FPUB
Konsep Ekosistem
Suatu EKOSISTEM merupakab 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.
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.
Boreal forests, for example, are characterized by the predominance of coniferous trees;
prairies are characterized by the predominance of grasses; the Arctic tundra is determined
partly by the harsh climatic zone. In most areas of the world, the human community is an
important and often dominant component of the ecosystem. Ecosystems include not only
natural areas (e.g., forests, lakes, marine coastal systems) but also human-constructed systems
(e.g., urban ecosystems, agroecosystems, impoundments). Human populations are
increasingly concentrated in urban ecosystems, and it is estimated that, by the year 2010, 50
percent of the world's population will be living in urban areas.
Suatu bentang-lahan terdiri atas mozaik ekosistem-ekosistem, termasuk kotakota, sungai, danau, system pertanian, dsb. Batas-batas yang tepat di antara
ekosistem-ekosistem tersebut seringkali sulit ditetapkan.
A functional system that includes an ecological community of organisms together
with the physical environment, interacting as a unit. Ecosystems are characterized by
flow of energy through food webs, production and degradation of organic matter, and
transformation and cycling of nutrient elements. This production of organic molecules
serves as the energy base for all biological activity within ecosystems. The consumption
of plants by herbivores (organisms that consume living plants or algae) and detritivores
(organisms that consume dead organic matter) serves to transfer energy stored in
photosynthetically produced organic molecules to other organisms. Coupled to the
production of organic matter and flow of energy is the cycling of elements.
All biological activity within ecosystems is supported by the production of organic
matter by autotrophs (organisms that can produce organic molecules such as glucose
from inorganic carbon dioxide; see illustration). More than 99% of autotrophic production
on Earth is through photosynthesis by plants, algae, and certain types of bacteria.
Collectively these organisms are termed photoautotrophs (autotrophs that use energy
from light to produce organic molecules). In addition to photosynthesis, some production
is conducted by chemoautotrophic bacteria (autotrophs that use energy stored in the
chemical bonds of inorganic molecules such as hydrogen sulfide to produce organic
molecules). The organic molecules produced by autotrophs are used to support the
organism's metabolism and reproduction, and to build new tissue. This new tissue is
consumed by herbivores or detritivores, which in turn are ultimately consumed by
predators or other detritivores.
Model aliran energy melalui ekosistem.
http://www.answers.com/topic/ecosystems-1#ixzz1f2eXwrp3
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 ajring-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 foto-autotrof 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 hasilpanen; penggunaan energy tanaman oleh hama tidak diperlukan karena hal ini berarti
mengambil energy dari produksi tanaman.
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
The living organisms in an agro-ecosystem are the biotic component. The organisms can be
analyzed as a food web that represents the transfer of material and energy from one group of
organisms to another. For a food web analysis, organisms are grouped by their function in
the flow of energy and nutrients rather than by their classification into genus and species. All
the plants in an agro-ecosystem make up the primary producers and provide the basis of the
food web. Plants capture solar energy through their leaves and in combination with water
and nutrients from the soil and carbon dioxide from the air generate plant material. The next
level of organisms is the herbivores that live off the nutrients and energy provided by plants
or primary producers. Many different types of organisms can be herbivores - birds, insects,
nematodes, fungi, bacteria and virus. In turn, the energy and nutrients in herbivores are
exploited for growth and reproduction by another group of organisms called secondary
consumers. Animals that live off the energy and nutrients in the substance of secondary
consumers are called tertiary consumers. Many different types of organisms can also be
primary, secondary and tertiary consumers.
Sumber: http://www.knowledgebank.irri.org/ipm/index.php/ecosystemecology….. diunduh 29/6/2011
Sumber: http://platforms.inibap.org/agro/concepts.html ….. diunduh 29/6/2011
The soil food web has many organisms feeding both on living and dead plant material. Thus,
the many organisms derive energy to grow and reproduce and eventually nutrients tied up in
plant and animal material is available again for plant growth.
Sumber: http://platforms.inibap.org/agro/concepts.html ….. diunduh 29/6/2011
Siklus Biogeokimia
In contrast to energy, which is lost from ecosystems as heat, chemical elements
(or nutrients) that compose molecules within organisms are not altered and may
repeatedly cycle between organisms and their environment. Approximately 40 elements
compose the bodies of organisms, with carbon, oxygen, hydrogen, nitrogen, and
phosphorus being the most abundant. If one of these elements is in short supply in the
environment, the growth of organisms can be limited, even if sufficient energy is
available. In particular, nitrogen and phosphorus are the elements most commonly
limiting organism growth. This limitation is illustrated by the widespread use of fertilizers,
which are applied to agricultural fields to alleviate nutrient limitation.
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/Cas
e3_Energy/Case3_Directions.htm ….. diunduh 29/6/2011
Carbon cycles between the atmosphere and terrestrial and oceanic ecosystems.
This cycling results, in part, from primary production and decomposition of organic
matter. Rates of primary production and decomposition, in turn, are regulated by the
supply of nitrogen, phosphorus, and iron. The combustion of fossil fuels is a recent
change in the global cycle that releases carbon that has long been buried within the
Earth's crust to the atmosphere. Carbon dioxide in the atmosphere traps heat on the
Earth's surface and is a major factor regulating the climate. This alteration of the global
carbon cycle along with the resulting impact on the climate is a major issue under
investigation by ecosystem ecologists.
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.
Carbon returns to the physical environment in a number of ways. Both plants and animals
respire, so they release CO2 during respiration. Luckily for animals, plants just happen to
consume more CO2 through photosynthesis than they can produce. Another route of CO2
back to the physical environment occurs through the death of plants and animals. When
organisms die, decomposers consume their bodies. In the process, some of the carbon
returns to the physical environment by way of fossilization. Some of it remains in the
biological environment as other organisms eat the decomposers. But by far, most of the
carbon returns to the physical environment through the respiration of CO2.
Sumber:
http://www.starsandseas.com/SAS%20Ecology/SAS%20chemcycles/cycle_carbon.htm .....
diunduh 29/6/2011
Siklus Nitrogen
Proteins, nucleic acids, and other organic chemicals contain nitrogen, so nitrogen is a very
important atom in biological organisms. Nitrogen makes up 79% of Earth's atmosphere, but most
organisms can not use nitrogen gas (N2). N2 enters the trophic system through a process called
nitrogen fixation. Bacteria found on the roots of some plants can fix N2 to organic molecules,
making proteins. Again, animals get their nitrogen by eating plants. But after this point, the nitrogen
cycle gets far more complicated than the carbon cycle. Animals releases nitrogen in their urine. Fish
releases NH3, but NH3 when concentrated, is poisonous to living organisms. So organisms must
dilute NH3 with a lot of water. Living in water, fish have no problem with this requirements, but
terrestrial animals have problems. They convert NH3 into urine, or another chemical that is not as
poisonous as NH3. The process of releases NH3 is called ammonification. Because NH3 is
poisonous, most of the NH3 which is released is untouchable. But soil bacteria have the ability to
assimilate NH3 into proteins. These bacteria effectively eats the NH3, and make proteins from it.
This process is called assimilation.
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
Siklus Phosphorus
Phosphorus is the key to energy in living organisms, for it is phosphorus that moves
energy from ATP to another molecule, driving an enzymatic reaction, or cellular
transport. Phosphorus is also the glue that holds DNA together, binding deoxyribose
sugars together, forming the backbone of the DNA molecule. Phosphorus does the
same job in RNA.
Again, the keystone of getting phosphorus into trophic systems are plants. Plants
absorb phosphorous from water and soil into their tissues, tying them to organic
molecules. Once taken up by plants, phosphorus is available for animals when they
consume the plants.
When plants and animals die, bacteria decomposes their bodies, releasing some of
the phosphorus back into the soil. Once in the soil, phosphorous can be moved 100s
to 1,000s of miles from were they were released by riding through streams and rivers.
So the water cycle plays a key role of moving phosphorus from ecosystem to
ecosystem.
In some cases, phosphorous will travel to a lake, and settle on the bottom. There, it
may turn into sedimentary rocks, limestone, to be released millions of years later. So
sedimentary rocks acts like a back, conserving much of the phosphorus for future
econs.
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 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)
Aliran hara di antara komponebn 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 henti-hentinya, 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 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. Tidak seluruh foton mempunyai tingkat energi yang cocok untuk
menggiatkan pigmen daun. Di atas 760 nm foton tidak memiliki cukup energi dan di
bawah 390 nm foton memiliki terlalu banyak energi, menyebabkan ionisasi dan
kerusakan pigmen. Hanya foton dengan panjang gelombang antara 390 dan 760 nm
memiliki tingkat energi yang cocok untuk fotosintesis. Karena penggiatan pigmen
merupakan akibat langsung interaksi antara foton dan pigmen, pengukuran cahaya yang
digunakan dalam fotosintesis seringkali berdasarkan densitas aliran foton, dan bukan
berdasarkan energi. Densitas aliran foton ialah jumlah foton yang menumbuk suatu luas
permukaan tertentu per satuan waktu. Karena panjang gelombang antara 400 dan 700
nm itu paling efisien digunakan dalam fotosintesis, pengukuran cahaya untuk
fotosintesis biasanya didasarkan pada densitas aliran foton dalam panjang gelombang
400 dan 700 nm tersebut (Michael,1994).
Sumber: http://ecology07.blogspot.com/2011_03_01_archive.html ….
Diunduh 29/6/2011
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.
Kesehatan Agro-ecosystem
One of the basic hypotheses in the research proposal is that the agro-ecosystem
health paradigm will provide a superior conceptual framework than agricultural
sustainability, which has remained 'without much empirical content because of the lack
of a comprehensive definition and analytical methodology' (ILRI 1998). Of course, it is
possible to distinguish between the two concepts, but for the practical purposes of this
research proposal they are fundamentally similar, essentially synonymous (this
comparison is developed in more detail in Smit and Smithers (1994). Once the term
'agro' is appended to 'ecosystem' we have explicitly included human components, such
that 'agro-ecosystem' is fundamentally equivalent to a broad definition of 'agriculture',
which includes ecological and human components.
“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 sifat-sifat 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 (agroecosystem 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 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.
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 agroecosystem. 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, selfregulatory 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, 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 agro-ecosystems.
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 agroecosystem. 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. Aktivitasaktivitas 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.
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 sediment-dwelling
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.
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
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 factor-faktor 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 these diseases are the result of arthropod-borne viruses (arboviruses)
which are transmitted to humans as a result of bites from blood-sucking arthropods.
Global climate change—particularly as it impacts both temperatures and
precipitation—is highly correlated with the prevalence of vector-borne diseases. For
example, viruses carried by mosquitoes, ticks, and other blood-sucking arthropods
generally have increased transmission rates with rising temperatures. St. Louis
encephalitis (SLE) serves as an example. The mosquito Culex tarsalis carries this virus.
The percentage of bites that results in transmission of SLE is dependent on temperature,
with greater transmission at higher temperatures.
The temperature dependence of vector-borne diseases is also well illustrated
with malaria. Malaria is endemic throughout the tropics, with a high prevalence in Africa,
the Indian subcontinent, Southeast Asia, and parts of South and Central America and
Mexico. Approximately 2.4 billion people live in areas of risk, with some 350 million new
infections occurring annually, resulting in approximately 2 million deaths, predominantly
in young children. Untreated malaria can become a life-long affliction—general
symptoms include fever, headache, and malaise.
The climate sensitivity of malaria arises owing to the nature of the interactions of
parasites, vectors, and hosts, all of which impact the ultimate transmission rates to
humans. The gestation time required for the parasite to become fully developed within
the mosquito host (a process termed sporogony) is from eight to thirty-five days. When
temperatures are in the range of 20°C to 27°C, the gestation time is reduced. Rainfall
and humidity also have an influence. Both drought and heavy rains tend to reduce the
population of mosquitoes that serve as vectors for malaria. In drier regions of the tropics,
low rainfall and humidity restricts the survival of mosquitoes. Severe flooding can result
in scouring of rivers and destruction of the breeding habitats for the mosquito vector,
while intermediate rainfall enhances vector production.
Ketidak-seimbangan Ekologis
Cholera is a serious and potentially fatal disease that is caused by the bacterium
Vibrio cholerae. While not nearly so prevalent as malaria, cases are nonetheless
numerous. In 1993, there were 296,206 new cases of cholera reported in South
America; 9,280 cases were reported in Mexico; 62,964 cases in Africa; and 64,599
cases in Asia. Most outbreaks in Asia, Africa, and South America have originated in
coastal areas. Symptoms of cholera include explosive watery diarrhea, vomiting, and
abdominal pain. The most recent pandemic of cholera involved more regions than at any
previous time in the twentieth century. The disease remains endemic in India,
Bangladesh, and Africa. Vibrio cholerae has also been found in the United States—in
the Gulf Coast region of Texas, Louisiana, and Florida; the Chesapeake Bay area; and
the California coast.
The increase in prevalence of V. cholerae has been strongly linked to degraded
coastal marine environments. Nutrient-enriched warmer coastal waters, resulting from a
combination of climate change and the use of fertilizers, provides an ideal environment
for reproduction and dissemination of V. cholerae. Recent outbreaks of cholera in
Bangladesh, for example, are closely correlated with higher sea surface temperatures.
V. cholerae attach to the surface of both freshwater and marine copepods (crustaceans),
as well as to roots and exposed surfaces of macrophytes (aquatic plants) such as the
water hyacinth, the most abundant aquatic plant in Bangladesh. Nutrient enrichment and
warmer temperatures give rise to algae blooms and an abundance of macrophytes. The
algae blooms provide abundant food for copepods, and the increasing copepod and
macrophyte populations provide V. cholerae with habitat. Subsequent dispersal of V.
cholerae into estuaries and fresh water bodies allows contact with humans who use
these waters for drinking and bathing. Global distribution of marine pathogens such as
V. cholerae is further facilitated by ballast water discharged from vessels. Ballast water
contains a virtual cocktail of pathogens, including V. cholerae.
Two other examples of how ecological imbalances lead to human health burdens
concern the increased prevalence of Lyme disease and hantavirus pulmonary disease.
Lyme disease, sonamed because it was first positively identified in Lyme, Connecticut, is
a crippling arthritic-type disease that is transmitted by spirochete-infected Ixodes ticks
(deer ticks). Ticks acquire the infection from rodents, and spend part of their life cycle on
deer. Three factors have combined to increase the risk to humans of contracting Lyme
disease, particularly in North America: (1) the elimination of natural deer predators,
particularly wolves; (2) reforestation of abandoned farmland has created more favorable
habitat for deer; and (3) the creation of suburban estates, which the deer find ideal
habitat for browsing. The net result is a rising deer population, which increases the
chances of humans coming into more contact with ticks.
Resistensi Antibiotik dan Praktek Pertanian
Antibiotic resistance is a growing threat to public health. Antibiotic resistant
strains of Streptococcus pneumoniae, a common bacterial pathogen in humans and a
leading cause of many infections, including chronic bronchitis, pneumonia, and
meningitis, have greatly increased in prevalence since the mid-1970s. In some regions
of the world, up to 70 percent of bacterial isolates taken from patients proved resistant to
penicillin and other b-lactam antibiotics. The use of large quantities of antibiotics in
agriculture and aquaculture appears to have been a key factor in the development of
antibiotic resistance by pathogens in farm animals that subsequently may also infect
humans. One of the most serious risks to human health from such practices is
vancomycin-resistant enterococci. The use of avoparcin, an animal growth promoter,
appears to have compromised the utility of vancomycin, the last antibiotic effective
against multi-drug-resistant bacteria. In areas where avoparcin has been used, such as
on farms in Denmark and Germany, vancomycin-resistant bacteria have been detected
in meat sold in supermarkets. Avoparcin was subsequently banned by the European
Union. Another example is the use of ofloxacin to protect chickens from infection and
thereby enhance their growth. This drug is closely related to ciprofloxacin, one of the
most widely used antibiotics in the year 2000. There have been cases of resistance to
ciprofloxacin directly related to its veterinary use. In the United Kingdom, ciprofloxacin
resistance developed in strains of campylobacter, a common cause of diarrhea. Multidrug-resistant strains of salmonella have been traced to European egg production.
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 immunecompetent 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 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 Food and Agriculture Organization of the United Nations estimates that more
than 40% of earth’s land surface is currently used for agriculture. And because so
much land has been converted to agriculture, habitat loss is recognized as the driving
force in biodiversity loss (FAO). This biodiversity loss often occurred in two steps, as in
the American Midwest, with the introduction of mixed farming carried out on small
farms and then with the widespread use of mechanized farming and monoculture
beginning after World War II. The decline in farmland biodiversity can now be traced
to changes in farming practices and increased agricultural intensity.
Peningkatan keaneka-ragaman
Heterogeneity (here, 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 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. Ecosistem-ekosistem di banyak daerah akan terancam,
dengan segala kekayaan biologisnya dan potensi manfaat materialnya. (Source: WPR)
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, 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
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 egokemandirian, 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 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.[4] 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 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.
Landless systems rely upon feed from outside the farm, representing the delinking 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.
Pendekatan untuk mereduksi limbah ternak dan pencemaran lingkungan:
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)
Pertanian-Ekologis = Ecoagriculture
Ecoagriculture describes landscapes that support both agricultural production
and biodiversity conservation, working in harmony together to improve the livelihoods of
rural communities. While many rural communities have independently practiced
ecoagriculture for thousands of years, over the past century many of these landscapes
have given way to segregated land use patterns, with some areas employing intensive
farming practices without regard to biodiversity impacts, and other areas fenced off
completely for habitat or watershed protection. A new ecoagriculture movement is now
gaining momentum to unite land managers and other stakeholders from diverse
environments to find compatible ways to conserve biodiversity while also enhancing
agricultural production.
"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 re-creating an eco-system, biodiversity, stability, fertility,
resilience and resistance are increased, there-by 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.
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]
Sustainable Agriculture in the United States was addressed by the 1990 farm
bill.[2] More recently, as consumer and retail demand for sustainable products has risen,
organizations such as Food Alliance and Protected Harvest have started to provide
measurement standards and certification programs for what constitutes a sustainably
grown crop.
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.
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 kacang-kacangan, 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 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 long-term 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
Sumber: http://www.seafriends.org.nz/enviro/soil/ecology.htm ..... diunduh 30/6/2011
Although air and sunlight are available everywhere on Earth, crops also depend
on soil nutrients and the availability of water. When farmers grow and harvest crops,
they remove some of these nutrients from the soil. Without replenishment, land suffers
from nutrient depletion and becomes either unusable or suffers from reduced yields.
Sustainable agriculture depends on replenishing the soil while minimizing the use of
non-renewable resources, such as natural gas (used in converting atmospheric nitrogen
into synthetic fertilizer), or mineral ores (e.g., phosphate). Possible sources of nitrogen
that would, in principle, be available indefinitely, include:
1. recycling crop waste and livestock or treated human manure
2. growing legume crops and forages such as peanuts or alfalfa that form
symbioses with nitrogen-fixing bacteria called rhizobia
3. industrial production of nitrogen by the Haber Process uses hydrogen, which
is currently derived from natural gas, (but this hydrogen could instead be
made by electrolysis of water using electricity (perhaps from solar cells or
windmills)) or
4. genetically engineering (non-legume) crops to form nitrogen-fixing symbioses
or fix nitrogen without microbial symbionts.
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 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.
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 (.[7]
When the production of food and fiber degrades the natural resource base, the
ability of future generations to produce and flourish decreases. The decline of ancient
civilizations in Mesopotamia, the Mediterranean region, Pre-Columbian southwest U.S.
and Central America is believed to have been strongly influenced by natural resource
degradation from non-sustainable farming and forestry practices. Water is the principal
resource that has helped agriculture and society to prosper, and it has been a major
limiting factor when mismanaged.
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).
¤ 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.
Menanam 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 funnel-shaped 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.
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.
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
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-and-burn 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]
Perlakuan Tanah pertanian
Soil steaming can be used as an ecological alternative to chemicals for soil
sterilization. Different methods are available to induce steam into the soil in order to kill
pests and increase soil health. Community and farm composting of kitchen, yard, and
farm organic waste can provide most if not all the required needs of local farms. This
composting could potentially be a reliable source of energy.
Apa itu Kompos?
Compost is a rich healthy humus type fertiliser and soil conditioner that results from
the decay of organic waste. Organic waste is used to describe a waste that was once
living such as grass, leaves, vegetable peelings, cooked food etc. Composting is
simply a means of creating the right conditions to accelerate this decay of waste.
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.
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 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.biotechnologygmo.gov.si/eng/gensko_spremenjeni_organizmi/index.html
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/Genetic
ally-modified-organisms-are-produced-using-scientificmethods-that-include ..... diunduh 30/6/2011
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
Access dan Intellectual Property
 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 intrinsik 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
95-100%, 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.
(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
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.
An agroecosystem can be viewed as a subset of a conventional ecosystem. As the
name implies, at the core of an agroecosystem lies the human activity of agriculture.
However, an agroecosystem is not restricted to the immediate site of agricultural
activity (e.g. the farm), but rather includes the region that is impacted by this
activity, usually by changes to the complexity of species assemblages and energy
flows, as well as to the net nutrient balance.
Traditionally an agroecosystem, particularly one managed intensively, is
characterized as having a simpler species composition and simpler energy and
nutrient flows than "natural" ecosystem.
Likewise, agroecosystems are often associated with elevated nutrient input, much of
which exits the farm leading to eutrophication of connected ecosystems not directly
engaged in agriculture.
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
Agroecosystems differ from natural ecosystems in several fundamental ways.
1. The energy that drives all autotrophic ecosystems, including agroecosystems,
is either directly or indirectly derived from solar energy. However, the energy
input to agroecosystems includes not only natural energy (sunlight) but also
processed energy (fossil fuels) as well as human and animal labor.
2. Biodiversity in agroecosystems is generally reduced by human management
in order to channel as much energy and nutrient flow as possible into a few
domesticated species.
3. Evolution is largely, but not entirely, through artificial selection where
commercially desirable phenotypic traits are increased through breeding
programs and genetic engineering.
4. Agroecosystems are usually examined from a range of perspectives including
energy flux, exchange of materials, nutrient budgets, and population and
community dynamics.
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 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 (huntergatherer) 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 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?
 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 hasilhasil pertanian dari konsumsi keluarga dapat dijual dan menghasilkan income bagi
keluarganya.
Prototipe Sistem Pengelolaan Agroekosistem Organik
Organic farming is an agricultural production system of foods and fibers in terms
of environmental, social and economic sustainability. It concentrates on soil fertilization
and paying respect to natural capabilities of plant, animal and agro-ecosystem. The
organic farming decreases external production factors and escapes the usage of
synthetic chemicals.
It mainly emphasizes on the usage of plant refuses, manures, vetch plants
(plants of pea family), green manures and other organic refuses for circulating nutrients
and energy in farms. This farming includes creating the environmental sustainability by
maintaining natural balance and biological diversity that the organic agro-ecosystem
management is similar to the nature and accompanies with using local wisdoms.
Therefore, the organic farming is an agricultural process relying on the nature with
mainly using biological processes to increase products and prevent pests and
accompanies with the circulation of resources using in farms for maximum benefit.
Hence, the organic farming principle will conform to the local conditions in terms of
economy, society, weather and culture. The organic agro-ecosystem management is an
important factor leading to the sustainably agricultural development.
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-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 agro-ecosystem 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.
Land management: 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.
Soil management: 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.
Water management: 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 m3. 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.
Plant and animal management: 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.
Pest management: 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 (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.
Waste management: 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 agroecosystem 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 agroecosystem 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.
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)
The improvement of existing practices and resources with the introduction of
alternative types of organic fertilizers are seen as the method most likely to succeed at
the present time. Some of the possibilities for maintaining and improving soil fertility
are addressed below.
Konservasi Tanah
No improvement in soil fertility can be contemplated until soil conservation
methods are practised. 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 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 (WyattSmith, 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 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
Additional inputs (fertilizer and technical) are required to increase present
productivity. At the stage when supplies of organic manure are insufficient, the use of
chemical fertilizer has to be considered. Though costly, and unreliable in supply in the
hill districts, the use of chemical fertilizers can supplement FYM in accessible areas. Its
careful use, preferably in combination with organic manure, could considerably increase
crop yields without causing much deterioration of soil quality.
Use of bio-fertilizers, flood water, and appropriate Rhizobium inoculation of
legume seeds may also help to reduce the pressure on the supply of FYM, for which
forests are presently being sacrificed to feed animals.
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.
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