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PRINSIP DASAR ANALISIS
AGROEKOSISTEM
Bahan kajian MK. Manajemen Agroekosistem FPUB Juli 2010
Diabstraksikan oleh
Prof Dr Ir Soemarno MS
Dosen Jur Tanah FPUB
Ekosistem pertanian menyediakan produk bagi manusia berupa
bahan pangan pakan, bioenergi, bahan farmasi , dan esensial bagi
kesejahteraan hidup manusia. Sistem-sistem pertanian ini bertumpu pada
jasa-jasa ejkosistem yang dihasilkan oleh ekosistem alamiah, termasuk
pollination, pengendalian hayati terhadap hama, pemeliharaan struktur dan
kesuburan tanah, siklus hara dan jasa-jasa hidrologis. Analisis awal
membuktikan bahwa nilai-nilai dari jasa-jasa ekosistem ini bagi pertanian
sangat banyak dan seringkali diabaikan.
Agroekosistem juga menghasilkan berbagai macam jasa-jasa
ekosistem, seperti regulasi kualitas tanah dan air, penangkapan dan
penyimpanan karbon, penunjang biodiversity dan jasa-jasa budaya.
Tergantung pada praktek-praktek pengelolaannya, pertanian juga dapat
menjadi sumber berbagai “disservices” (dampak negatif), termasuk hilangnya
habitat liar (wildlife habitat), runoff hara, sedimentasi saluran air, emisi gas
rumah kaca, dan keracunan pestisida pada manusia dan jasad non-target.
Tradeoffs yang terjadi di antara jasa-jasa yang bermanfaat dan dampak
negative tersebut harus dievaluasi secara spatial, temporer dan
reversibilitasnya.
Beragam metode yang efektif untuk menilai jasa-jasa ekosistem telah
tersedia, sehingga potensi untuk mewujudkan scenario ‘win–win’ menjadi
semakin besar. Pada semua skenario, praktek pengelolaan pertanian yang
tepat menjadi titik kritis untuk mewujudkan manfaat jasa-jasa ekosistem dan
mereduksi dampak negative akibat aktivitas pertanian.
1. Hierarkhis Agro-ekosistem
In this learning resource, we consider “agro-ecosystems” to result from the
manipulation of natural and biological resources by social groups. Agroecosystems therefore represent an integration of social and ecological
systems, and can be considered from different disciplinary standpoints
(social, economic, ecological) as well at several different levels of
organization (crop, farm, community, watershed, etc). For example:
 Geographers and macroeconomists typically focus their attention
at the national level. Typically their analysis looks at patterns of
land use for national-level planning purposes and policy purposes.
 Development project teams (usually interdisciplinary, including
economists, agricultural scientists and sociologists) often work at
the level of (sub)region within a country. They focus on the
different agricultural (sub) zones and stakeholders, the
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relationships between these, how productive activities fit with
national and international markets, and the forms of organization
at community and regional level. Increasingly (because of
sustainability concerns), such teams are focussing on the
management of natural resources at a watershed level.
 NGOs often focus at the community level. They look at the
interaction between different social groups and organization within
the community, infrastructure, wellbeing and productive needs of
the different social groups.
Farming systems teams (micro-economists, crop and livestock
scientists) have traditionally looked at the farm level; how the
different activities (crops, livestock, etc) exploit the natural
resources available and interact to maximize the income or food
production at the farm level (increasingly, however, the ”farming
systems” perspective has widened to look at community and
watershed level interactions).
 Crop and livestock
scientists (agronomists,
breeders,
entomologists, pathologists, etc.) typically focus on crops and
livestock at the field and herd levels, respectively, with the
objective of maximising crop and livestock productivity.
 We could go on to consider plant, organ level, etc.)
In the remainder of this learning resource, we will largely focus on
natural resource and productivity aspects of agro-ecosystems.
Social and economic aspects will be considered in more detail in
other learning resources.
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Gambar 1. Hierarkhis Agro-ekosistem
Sumber: ICRA (www.icra-edu.org) by Richard Hawkins, using material prepared for
ICRA by Clive Lightfoot.
2. Parameter dan Variabel
All of the above levels can be relevant to ARD, depending on the objectives of
the teams and client institutions. The level of analysis primarily depends upon
institutional mandates, which factors are considered “variables”, and which
are considered as “parameters”.
 Variables are those factors that can be changed through the
actions of the team, or the project or programme that a team
prepares. These factors can be considered to be “internal” to the
system of interest. The objectives of any programme or project
proposed on the basis of a systems analysis will be based on
variables.
 Parameters are those factors that a team considers as
unchangeable, for the purposes of their analyses and work. These
factors can be considered to be “external” to the system of interest
(i.e. forming the “environment” of the system). These external
factors often act as “driving forces” of the system (see learning
resource on scenarios and strategies), and their future status
might need to be considered as the focus of “critical assumptions”
(see learning resource on objectives and logical frameworks).
For example, most agricultural professionals consider production technology
(crop choice, varieties, input use, etc.) to be changeable, and much research
and extension effort is dedicated to this end. Most agricultural professionals
consider national level policies (e.g. input subsidies, price controls) to be
“fixed” – but they nevertheless need to consider the impact of any future and
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probable changes of these policies on the technologies they are developing
or promoting. More regional or local policies (e.g. the management of an
irrigation system) might be considered a variable or a parameter, depending
on the team and the stakeholders who can be involved in any proposed
programme or project.
Keterkaitan antar komponen (parameter) agroekosistem (Sumber:
http://www.nzdl.org/cgi-bin/library.cgi?e=d-00000-00---off-0envl--00-0----0-10-0---0--0direct-10---4-------0-1l--11-en-50---20-about---00-0-1-00-0-0-11-1-0utfZz-800&cl=CL1.5&d=HASH0182f7010e9fdb7f2eae7b06&gt=2 ….. diunduh 8/7/2011)
The agro-ecosystem is the agricultural production system and comprises four
components: food and cash agriculture, aquaculture, animal husbandry, and
forestry. Among the components, the interaction through land is a matter of
competition for space, while within each component the landwater interaction
may affect, adversely or Positively, its production process. However, among the
components water acts as an integrator due to its ability to flow from one to the
other. Besides these interactions, the possibility exists for inter-component man
induced interactions.
3. Interaksi Antar Komponen Agro-ekosistem
From a systems perspective, it is important to consider not just the
components of the system of interest, but also the interactions between
components. Ignoring these interactions often leads to the poor “fit” of
agricultural technologies or policies, and result either in rejection (of the
technologies) by farmers or unintended consequences (of the policies).
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Pada tingkat usahatani, interaksi-interaksi tersebut meliputi:
 Output-output dari satu aktivitas digunakan sebagai input untuk
aktivitas lainnya.
o Penggunaan jerami tanaman atau residu tanaman untuk
pakan ternak. A typical consequence is the rejection by
farmers of short-straw varieties of cereals such as rice and
sorghum, due to the reduced biomass and the lower
palatability to livestock of dwarf rice varieties (which have high
levels of silica in the stem).
O Penggunaan kotoran hewan ternak untuk pupuk
tanaman (when alternative sources of fertility maintenance
might be needed as grazing land decreases and/or
mechanization is introduced).

 Penanaman dua jenis tanaman pada petakan lahan yang sama
pada tahun atau musim tanam yang sama.
O Intercropping or mixed cropping – where two or more crops are
planted at the same or similar times (e.g. maize accompanied
with beans, cowpeas, sweet potatoes, rice, squash, etc. in
many small holdings);
O Relay cropping – where one crop is planted on the same plot
towards the end of the life cycle of another (e.g. beans are
often planted after the maize flowers and is doubled over in
many parts of Latin America);
o Sequential crops – where one crop is planted after the harvest
of another.
In such cases, the adoption of higher yielding varieties of one crop (which
often involves either a denser vegetation or a longer duration of the crop in
the field) may adversely affect the yields of accompanying or sequential
crops.
Pada tingkat komunal atau regional, contoh-contoh interaksi adalah:
 The use of an input by one type of farmer of the output of another
type of farmer (e.g. specialised livestock farmers who buy the
maize residue from specialised crop farmers);
 Different and competing uses of the same resource by different
stakeholders; e.g.:
o Land - the conversion of communal land, used by pastoralists
as specialized grazing reserves in dry years, to state-owned
wheat farms in some parts of Africa.
o Water - the abstraction (or contamination) of stream water for
irrigation by upstream crop farmers leading to lack (or
pollution) of water used by downstream livestock owners).
o Labour – small farmers supplying wage labour for sugar or
coffee harvest on plantations, leading to late planting or nonweeding on small holders own fields; farmers without
livestock hiring their manual labour to ox-owners in exchange
for ploughing services (which may then arrive later than the
optimum planting time).
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There are many such examples, at the different levels of the hierarchy of
agroecosystems. The important point is that maximising the output of one
system (e.g. a crop) may not lead to the optimum output of a higher system
(e.g. the farm) of which the first system is a component. The emergent
property of the system is more than the sum of the parts.
Interaksi secara teoritis antara agroekosistem, sumberdaya manusia,
teknologi dan capital di wilayah pantai bagian dari DAS Citarum.
(Sumber: http://www.nzdl.org/cgi-bin/library.cgi?e=d-00000-00---off-0envl--00-0----010-0---0---0direct-10---4-------0-1l--11-en-50---20-about---00-0-1-00-0-0-11-1-0utfZz-800&cl=CL1.5&d=HASH0182f7010e9fdb7f2eae7b06&gt=2 ….. diunduh 8/7/2011)
Technology applied to and capital needed in resource utilization
should be relevant to conditions of the existing human and natural
resources, should increase the efficiency of the activities to obtain
beneficial outputs, and should minimize the harmful or nonutilizable outputs of each process. Both technology and capital may
already exist as a part of the human resources or may be introduced
into the system. Interactions of the three major components related
to integrated development of resource utilization in the coastal part
of the Citarum watershed describes the activities or decisions in
resource (agroecosystem) utilization or exploitation in obtaining
products and making them available directly or indirectly to the
society. It also describes the decisions or activities needed to
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improve the productivity of the human resource and the capability
to sustain or improve the resource base, which will provide not
only the society's needs but also improved environmental
conditions.
4. Komponen-komponen Sistem
Cara sederhana untuk mengidentifikasi berbagai komponen dalam suatu
system pada level tertentu adalah menggunakan peta. Peta-peta dapat
menunjukkan:
 Agro-ecological “niches” (e.g. soil types, vegetation types, crops,
woods, water sources, etc);
 Infrastructure (roads, wells, etc);
 Social units (different stakeholders, social groups, types of farmer,
markets, etc).
At a national or regional level, published geographical maps show
infrastructure (roads, rivers, etc.). Usually climate, soil and/or vegetation
maps are also available; satellite images or aerial photographs may also
show different types of vegetation, etc.
At a more local level, more useful information can be gained by getting
local stakeholders to draw a map or transect. Most people can draw a map,
even people with little formal schooling, and the maps show the resources
and features that are important to them (which an outsider might overlook).
The visual nature of a map makes it easy for local people and outsiders to
share knowledge, and to compare local and “formal” knowledge systems (e.g.
local soil names with internationally recognised soil classifications).
Transek agroekosistem juga dapat digunakan untuk mengidentifikasi
komponen-komponen yang ada dalam suatu agroekosistem.
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Transek agroekosistem menunjukkan komponen-komponen agroekosistem dan
keterjkaitan antar agroekosistem yang ada (Sumber: http://www.nzdl.org/gsdlmod?e=d00000-00---off-0fnl2.2--00-0----0-10-0---0---0direct-10---4-------0-1l--11-en-50---20about---00-0-1-00---4----0-0-11-1-0utfZz-800&cl=CL3.33&d=HASH012b7a70e5e4e0a26a903e7e.6.6&gc=1 ….. diakses
6/7/2011)
Simplified structure of the CENTURY agroecosystem model (Parton et
al 1987, 1995) indicating the physical environmental controls and the
set of land use management options implemented.
The dynamics of the agroecosystem will depend on the joint influence
of the physical environment and the specific mix of land use practices
implemented with a location. The land use decisions are controlled by a
number of factors economics, policy, technological advancements, and
socio- cultural factors.
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Sumber: http://www.ncgia.ucsb.edu/conf/SANTA_FE_CDROM/sf_papers/ojima_dennis/ojimapar.html ..... diunduh 3/7/2011)
Dalam suatu agroekosistem juga terjadi siklus energy. Crop plants are at the
bottom of the food web, whereas consumers (like you) are at the top. Since
energy goes into crop plants from the sun, and the energy in the crops is
used/consumed by humans and livestock, the energy in crop production can
be viewed from two perspectives: energy input into crop production, and
energy output into food products that can be consumed by livestock or
humans. Also, since many people eat meat, some crop energy is saved in
animals and then consumed by humans in the form of meat, eggs, and milk.
The goal of this case study is to help you think about energy flow in
agroecosystems from both of these perspectives.
Gliessman dalam bukunya tentang Agroekologi melukiskan aliran energy dari
satu tingkat ke tingkat selanjutnya dalam jaring-jaring makanan. 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.
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Aliran energy dalam jaring-jaring makanan menurut Gliessman
Sumber:
http://www.acad.carleton.edu/curricular/BIOL/classes/bio160/ClassResource
s/Case_Studies/Case3_Energy/Case3_Directions.htm ..... diunduh 6/7/2011
5. Aliran Sumberdaya
Once the different components of the relevant system are identified, an idea
of the potential interactions between these can be gained by tracking the
flows of resources between the different components. These resources can
include:
Material (grain, straw, fertilizers, milk, units of nitrogen, water, etc)
Tenaga atau energi (human labour, animal power, machine
power)
Finansial (expenses, income, credit, savings, etc)
Informasi (tentang pasar, harga, teknologi, kebijakan, dll.)
Sumberdaya ini semuanya dapat dianalisis dalam dua dimensi.
5.1. Dimensi Spatial
The flows of resources between different system components can be
illustrated and analysed using flow diagrams. These can be stylised
(conceptual models) or based on more pictorial maps or transects.
At the field or plot level, the resources of interest are usually
nutrients. For example, trees (as in agro-forestry systems) might fix nitrogen,
or extract nutrients from a deeper soil layer, which are then made available
through decomposition of the foliage to associated annual crops. In Central
America, some coffee plantations consist of 3 strata: A tall tree species, such
as Cordia spp., which provides shade and long-term income from the timber;
a heavily pruned leguminous tree, such as Erythrina spp., which can fix up to
200 kg/ha nitrogen, and the coffee bushes which provide the main annual
income.
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Kebun kopi yang menunjukkan struktur tiga strata: Pohon naungan, tanaman kopi, dan
penutup tanah (Sumber:
http://picasaweb.google.com/BobLang23/60PicturesFromIndia ..... diunduh 6/7/2011)
At the farm level, the relevant resource flows include labour and cash, and
how these are deployed between different possible activities within and off the
farm; how the outputs of one activity (e.g. a cropping system) might act as
inputs for another; and the inputs and outputs of the farm system. A stylised
and simplified farm system is represented below.
Sumber: ICRA (www.icra-edu.org) by Richard Hawkins, using material prepared for
ICRA by Clive Lightfoot.
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Diagram alir Sistem Pertanian Terpadu
(Source: Preston, T. R. 2000. Livestock production from local resources in an
integrated farming system ; a Sustainable alternative for the benefit of Small scale
Farmers and the environment. workshop-seminar on making better use of local feed
resources SAREC- UAF). (http://www.mekarn.org/msc200103/theses03/santhlitrevapr27.htm….. diunduh 8/7/2011)
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Hubungan antara INPUT, PROSES dan OUTPUT dalam suatu FARM
(Sumber: http://www.geographypages.co.uk/farmsys.htm….. diunduh
8/7/2011)
FARMING SYSTEMS
A farm is a system in that it has INPUTS, PROCESSES and
OUTPUTS
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INPUTS - these are things that go into the farm and may be split into
Physical Inputs (e.g. amount of rain, soil) and Human Inputs (e.g. labour,
money etc.)
PROCESSES - these are things which take place on the farm in order
to convert the inputs to outputs (e.g. sowing, weeding, harvesting etc.)
OUTPUTS - these are the products from the farm (i.e. wheat, barley,
cattle)
Depending on the type of farming e.g. arable/ pastoral, commerical /
subsisitence, the type and amount of inputs, processes and outputs will vary.
(Sumber: http://geobytesgcse.blogspot.com/2008/04/farming-introduction-farmingsystem.html ….. diunduh 8/7/2011)
At the community or regional level, the resource flows include not only the
marketing systems but also information and financial systems. There may
also be significant material and labour flows between different types of
household or farm. In addition the use of water as a regional resource is
increasingly becoming important: it is not uncommon to find that conflicts over
water use are a major issue in many rural communities.
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Keterkaitan antar komponen agroekosistem dalam suatu kawasan (Sumber:
http://www.agnet.org/library/eb/461/ ….. diunduh 8/7/2011)
5.2. Dimensi Temporer
Agro-ecosystems are not static. They change with time, in a regular way over
cycles or one or more years. They also evolve over longer time scales. It is
important to understand these changes.
Siklus Tahunan/ Musiman
Agricultural practices and resource flows are tightly linked to the changes in
seasons. For example, farms in the humid tropics may have two or three
cropping seasons in a calendar year. In areas with more marked dry and wet
seasons, the timing of planting, weeding and harvesting is dependent on
rainfall or temperature patterns, resulting in resources (labour, cash, food,
etc.) being more plentiful or scarce in certain months. A visit to a farm or static
analysis of an agroecosystem at one time of the year (often during the dry
season, when farmers have more time to interact with outsiders) may give a
different picture of resource use to that at other times.
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Crop rotation is the practice of growing a series of dissimilar types of crops in
the same area in sequential seasons for various benefits such as to avoid the
build up of pathogens and pests that often occurs when one species is
continuously cropped. A traditional element of crop rotation is the
replenishment of nitrogen through the use of green manure in sequence with
cereals and other crops. It is one component of polyculture. Crop rotation can
also improve soil structure and fertility by alternating deep-rooted and shallowrooted plants.
Crop rotation avoids a decrease in soil fertility, as growing the same crop in the
same place for many years in a row disproportionately depletes the soil of
certain nutrients. With rotation, crops that leaches the soil of one kind of
nutrient is followed during the next growing season by a dissimilar crop that
returns that nutrient to the soil or draws a different ratio of nutrients, for
example, rice followed by cotton. By crop rotation farmers can keep their fields
under continuous production, without the need to let them lie fallow, and
reducing the need for artificial fertilizers, both of which can be expensive.
Rotating crops adds nutrients to the soil. Legumes, plants of the family
Fabaceae, for instance, have nodules on their roots which contain nitrogenfixing bacteria. It therefore makes good sense agriculturally to alternate them
with cereals (family Poaceae) and other plants that require nitrates. An extremely
common modern crop rotation is alternating soybeans and maize (corn). In
subsistence farming, it also makes good nutritional sense to grow beans and
grain at the same time in different fields.
Crop rotation is a type of cultural control that is also used to control pests and
diseases that can become established in the soil over time. The changing of
crops in a sequence tends to decrease the population level of pests. Plants within
the same taxonomic family tend to have similar pests and pathogens. By
regularly changing the planting location, the pest cycles can be broken or
limited. For example, root-knot nematode is a serious problem for some plants
in warm climates and sandy soils, where it slowly builds up to high levels in the
soil, and can severely damage plant productivity by cutting off circulation from
the plant roots. Growing a crop that is not a host for root-knot nematode for
one season greatly reduces the level of the nematode in the soil, thus making it
possible to grow a susceptible crop the following season without needing soil
fumigation.
It is also difficult to control weeds similar to the crop which may contaminate
the final produce. For instance, ergot in weed grasses is difficult to separate
from harvested grain. A different crop allows the weeds to be eliminated,
breaking the ergot cycle. This principle is of particular use in organic farming,
where pest control may be achieved without synthetic pesticides. A general
effect of crop rotation is that there is a geographic mixing of crops, which can
slow the spread of pests and diseases during the growing season. The different
crops can also reduce the effects of adverse weather for the individual farmer
and, by requiring planting and harvest at different times, allow more land to be
farmed with the same amount of machinery and labor. The choice and sequence
of rotation crops depends on the nature of the soil, the climate, and
precipitation which together determine the type of plants that may be cultivated.
Other important aspects of farming such as crop marketing and economic
variables must also be considered when deciding crop rotations.
Benefits and Risks of Crop Rotation
Other benefits of rotation cropping systems include production costs
advantages. Overall financial risks are more widely distributed over more diverse
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production of crops and/or livestock. Less reliance is placed on purchased
inputs and overtime crops can maintain production goals with fewer inputs.
This in tandem with greater short and long term yields makes rotation a
powerful tool for improving agricultural systems.
Risks of crop rotation include less overall profitability due to decreased acreage
of the most valuable crop. Greater investment and lower relative efficiency in
machinery used for different crops is also a possible outcome. More complex
rotations require more crop species and livestock. This means the farmer must
have additional skills and make more time and equipment investments initially.
Also the more complex the system, the less flexible it becomes in terms of long
term land management. Starting a rotation of a new crop may add profitability
and farm resilience over time, but benefits are initially subject to being overshadowed by volatile markets or high startup investments which can take time
to overcome. Overall many farmers and agronomists agree finding a suitable
rotation can benefit the overall productivity and sustainability of the farm.
The rotation of crops is not only necessary to offer a diverse "diet" to the
soil micro organisms, but as they root at different soil depths, they are
capable of exploring different soil layers for nutrients. Nutrients that have
been leached to deeper layers and that are no longer available for the
commercial crop, can be "recycled" by the crops in rotation. This way the
rotation crops function as biological pumps. Furthermore, a diversity of
crops in rotation leads to a diverse soil flora and fauna, as the roots excrete
different organic substances that attract different types of bacteria and
fungi, which in turn, play an important role in the transformation of these
substances into plant available nutrients. Crop rotation also has an
important phytosanitary function as it prevents the carry over of cropspecific pests and diseases from one crop to the next via crop residues
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Contoh pergiliran tanaman untuk memelihara kesuburan tanah dan memutus
siklus pembawa penyakit.
Sumber: http://www.fao.org/ag/ca/1b.html….. diunduh 8/7/2011)
Siklus Multi-tahun
Many agricultural systems also follow a cyclical pattern over several
years, with a period of cropping being followed by a fallow period with the
regrowth of grasses, shrubs or trees. Fallow periods can last anything from
one to several years, and during this period crop weed populations are
suppressed and fertility accumulates in the foliage of the fallow vegetation
(which often includes nitrogen fixing trees). Before the next cropping period
these nutrients are usually released through burning or mulching. During the
cropping period, which can also last from one to several years, sequences of
different crops are used, with those most demanding in terms of soil fertility
(e.g. maize) planted before those less demanding (e.g. cassava).
Crop Rotation is a technique used in organic gardening in order to prevent pest
and disease build up as well as to replenish the soil. This is done by rotating
the position of crop families from year to year. Many adult pests and their
offspring overwinter in the soil. By rotating your crops you can disrupt the
insects’ life cycle and prevent outbreaks.
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Oftentimes pests attack plants within the same family. For example, leaf
miners attack members of the Goosefoot Family, such as spinach and Swiss
chard. If members of this family are planted in the same space year after year,
pest populations can increase, reaching unmanageable numbers very quickly.
Crop rotation is a strategy that helps to prevent this problem. By planting
members of the Goosefoot Family in different locations throughout the garden
you can ensure that the leaf miner population is kept in check.
Members of the Nightshade Family are another example; tomatoes and
potatoes share the same disease problems. For example, the fungus that
causes late blight can survive in potato tubers left in the ground from the year
before. If you plant tomatoes in this same area the following year they will be
sure to get the disease.
Another reason to rotate different crops in a particular area is for soil health.
Different plants/plant families have different nutritional needs. Varying the
crops in an area each year will help keep the nutrient level of the soil
balanced. Legumes planted as part of the rotation will help to replenish usable
nitrogen in the soil.
Steps to crop rotation:
1. Organize your garden into different areas, either by garden beds or groups
of beds.
2. Get to know your vegetable families.
3. Plant each area with members of the same family.
4. Rotate these plantings each year. Allow for at least three years before you
re-plant the same family in a given space. This is especially important for the
Nightshade Family.
If your space is limited and you are unable to plan for a different area of your
garden for each vegetable family, you are in luck! Some vegetable families
grow well together. Here are a few tips for planting with limited space:

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Corn can be planted with members of the Squash Family or beans.
Members of the Onion Family can be planted with any group except
for legumes.
Leafy crops can be planted with members of the Cabbage Family.
Root crops such as beets, carrots and radishes can be planted among
any group, and replanted in various areas as succession crops.
Use companion planting methods to make the most of your garden
space.
Keep track of your plantings and rotation and note your successes.
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A few examples of rotation plans are provided below:
Sistem rotasi tanaman empat-tahun
(Sumber: http://porchsidegardening.wordpress.com/2010/07/23/croprotation/….. diunduh 8/7/2011)
This simple rotation suggested by the Penn State Cooperative
extension offers a good rotation scheme for those with small areas.
This rotation allows room for creative companion planting. The
principles behind this plan are pretty simple. Crops in the Cabbage
Family are heavy feeders; they do well when they are planted after
legumes. Nightshades are planted together and only planted in the
same area every four years. Squash and corn do well together and
save space when planted together.
Sistem rotasi tanaman delapan tahunan
(Sumber: http://porchsidegardening.wordpress.com/2010/07/23/croprotation/….. diunduh 8/7/2011)
If you have enough room for eight different groups, this rotation is very well planned
out. Coleman reasons that both potatoes and squash are good “cleaning” crops,
meaning that they cover the soil and prevent weeds from taking root. These plants are
then followed by root crops. Beans add nitrogen to the soil for tomatoes and peas add
21
more nitrogen, building up nutrients in the soil for heavy feeders like the Cabbage
Family and corn. Potatoes are planted opposite tomatoes in the rotation, leaving three
years between these pest prone plants.
22
Kecenderungan jangka panjang
Over a longer period of time – years or even decades – farmers
change their farming systems to respond “driving forces”: changes in markets,
product prices, population pressure, disease (in humans, livestock and
crops), infrastructure development (roads, irrigation), etc. There are few areas
of the world where farms are similar to those of a generation ago: in this
sense, “traditional” farming rarely exists.
In some areas, farms are becoming progressively smaller as
inheritance between children divides the land holdings between new families.
As the ratio of land to labour decreases, farming systems become more
intensive, fallow periods are shortened, grazing areas and livestock numbers
per household decrease. However, this is not to say that increasing
population pressure inevitably leads to land degradation: where production is
linked to markets (e.g. for higher value products such as vegetables),
increasing income can take the pressure off extensive grain or livestock
production, and justify investments in soil fertility maintenance.
In other areas farms are becoming larger, as urbanisation and growth
in nonagricultural economic activity leads to people leaving agriculture. In this
case the ratio of labour to land often decreases, with emphasis on labour
saving machinery. Additionally, changes in international trade lead to farms
changing commodities and specializing, when information and financial flows
become critical.
In other words, change is constant. The impact of agricultural research
and development efforts typically takes several years to take full effect, which
means that agro-ecosystems need to be designed for future scenarios – not
those of today.
6. Pendekatan untuk Analisis Jasa-jasa Ekosistem
The value of ecosystem services has been estimated in various ways.
In general, the framework has three main parts:
(i)
measuring the provision of ecosystem services;
(ii)
determining the monetary value of ecosystem services;
(iii)
designing policy tools for managing ecosystem services.
Basic knowledge about ecosystem structure and function is increasing
at a rapid pace, but we know less about how these factors determine the
provision of a complete range of ecosystem services from an individual
ecosystem (NRC 2005). In practice, most studies focus on estimating the
provision of one or two well understood ecosystem services. Better
understanding of the processes that influence ecosystem services could allow
us to predict the outputs of a range of ecosystem services, given particular
ecosystem characteristics and perturbations to those ecosystems. That is, an
‘ecological production function’ might be generated. Despite recent advances,
this is an area of research that still needs considerable attention.
The second step of valuation of ecosystem services typically includes
both market and non-market valuation. Valuing the provisioning services that
derive from agriculture is relatively straightforward, since agricultural
commodities are traded in local, regional or global markets. Some ecosystem
23
services provide an essential input to agricultural production, and their value
can be measured by estimating the change in the quantity or quality of
agricultural production when the services are removed or degraded. This
approach has been used to estimate the value of pollination services and
biological control services. Values for such services can also be estimated by
measuring replacement costs, such as pesticides replacing natural pest
control and hand-pollination or beehive rental replacing pollination.
Non-market valuation methods have been used for many years to
measure both the use value and the non-use value of various environmental
amenities. Non-market valuation can be based on revealed preference
(behaviour expressed through consumer choices) or stated preference (e.g.
attitudes expressed through surveys). In contingent valuation surveys, for
example, consumers are asked what they would be willing to pay for the
ecosystem service. Another approach is to ask producers—in this case
farmers—what they would be willing to accept to supply the ecosystem
service.
The overarching goal of measuring and valuing ecosystem services is
to use that information to shape policies and incentives for better
management of ecosystems and natural resources. One of the inherent
difficulties of managing ecosystem services is that the individuals who control
the supply of such services, such as farmers and other land managers, are
not always the beneficiaries of these services. Many ecosystem services are
public goods. While farmers do benefit from a variety of ecosystem services,
their activities may strongly influence the delivery of services to other
individuals who do not control the production of these services. Examples
include the impact of farming practices on downstream water supply and
purity and regional pest management. The challenge is to use emerging
information about ecological production functions and valuation to develop
policies and incentives that are easily implemented and adaptable to
changing ecological and market conditions.
One approach to incentives is to provide payments for environmental
services, through government programmes or private sector initiatives.
Historically, the US has provided support for soil conservation investments
and other readily observable practices to maintain or enhance certain
ecosystem services. In the US, the Conservation Security Program of the
2002 farm bill established payments for environmental services, and many
European countries have also provided governmental support for
environmentally sound farming practices that support ecosystem services.
Agri-environment schemes are intended to moderate the negative
environmental effects of intensive agriculture by providing financial incentives
to farmers to adopt environmentally sound agricultural practices. The impacts
of these projects are variable, however, and their success is debated. A
recent evaluation of over 200 paired fields in five European countries
indicated that agri-environment programmes had marginal to moderate
positive impacts on biodiversity, but largely failed to benefit rare or
endangered species.
The Economics of Ecosystems and Biodiversity (TEEB) led by the
United Nations Environment Programme (UNEP), is an international effort
designed to integrate science, economics and policy around biodiversity and
ecosystem services. A recent report for policy-makers highlights the link
between poverty and the loss of ecosystems and biodiversity, with the intent
of facilitating the development of effective policy in this area. Another
24
approach is the establishment of markets for pollution credits, including the
growing global carbon market operating under various cap and trade
initiatives, such as the European Union Emission Trading System.
7. Jasa-jasa Ekosistem Alamiah yang mengalir ke Ekosistem
Pertanian
The production of agricultural goods is highly dependent on the
services provided by neighbouring natural ecosystems, but only recently have
there been attempts to estimate the value of many of those services to
agricultural enterprises. Some services are more easily quantified than
others, to the extent that they are essential to crop production or they
substitute directly for purchased inputs.
(a) Pengendalian Hayati Hama
Biological control of pest insects in agroecosystems is an important
ecosystem service that is often supported by natural ecosystems. Non-crop
habitats provide the habitat and diverse food resources required for arthropod
predators and parasitoids, insectivorous birds and bats, and microbial
pathogens that act as natural enemies to agricultural pests and provide
biological control services in agroecosystems. These biological control
services can reduce populations of pest insects and weeds in agriculture,
thereby reducing the need for pesticides.
Because the ecosystem services provided by natural enemies can
substitute directly for insecticides and crop losses to pests can often be
measured, the economic value of these services is more easily estimated
than many other services. For example, an analysis of the value of natural
enemy suppression of soya bean aphid in soya bean indicated that this
ecosystem service was worth a minimum of US$239 million in four US states
in 2007–2008 alone (Landis et al. 2008). Since this is an estimate of the value
of suppressing a single pest in one crop, the total value of biological control
services is clearly much larger. Natural pest control services have been
estimated to save $13.6 billion per year in agricultural crops in the US (Losey
& Vaughan 2006). This estimate is based on the value of crop losses to insect
damage as well as the value of expenditures on insecticides. Studies suggest
that insect predators and parasitoids account for approximately 33 per cent of
natural pest control (Hawkins et al. 1999), therefore the value of pest control
services attributed to insect natural enemies has been estimated at $4.5
billion per year (Losey & Vaughan 2006).
(b) Pollination
Pollination is another important ecosystem service to agriculture that
is provided by natural habitats in agricultural landscapes. Approximately 65
per cent of plant species require pollination by animals, and an analysis of
data from 200 countries indicated that 75 per cent of crop species of global
significance for food production rely on animal pollination, primarily by insects
(Klein et al. 2007). Of the most important animal-pollinated crops, over 40 per
cent depend on wild pollinators, often in addition to domesticated honeybees.
Only 35–40% of the total volume of food crop production comes from animalpollinated crops, however, since cereal crops typically do not depend on
25
animal pollination. Aizen et al. (2009) used data from the United Nations Food
and Agriculture Organization (FAO) on the production of 87 globally important
crops during 1961–2006 to estimate that the consequences of a complete
loss of pollinators for total global agricultural production would be a reduction
of 3–8%. The percentage increase in total cultivated area that would be
required to compensate for the decrease in production was much higher,
particularly in the developing world where agriculture is more pollinatordependent.
Like biological control, pollination services are more readily quantified
than many other services. Early estimates of the value of pollination services
were based on the total value of animal-pollinated crops, but recent estimates
have been more nuanced. Since most crops are only partly dependent on
animal pollination, a dependence ratio or a measure of the proportion
reduction in production in the absence of pollinators can provide a better
approximation of production losses in the absence of pollinators. Clearly,
these estimates are also fairly crude and intended to provide a broad-brush
assessment of potential economic benefits. Moreover, most estimates do not
take into account potential changes in the value of each commodity as
demand increases owing to reduced crop production.
A recent assessment of agricultural vulnerability to loss of pollination
services based on the ratio of the economic value of insect pollination to the
economic value of the crop indicated an overall vulnerability of 9.5 per cent,
but vulnerability varied significantly among types of commodities as well as by
geographical region (Gallai et al. 2009). Stimulant crops (coffee, cacao, and
tea), nuts, fruits and edible oil crops were predicted to be particularly
vulnerable to the loss of pollination services (table 1). The economic impact of
insect pollination on world food production in 2005 in the 162 FAO member
countries has been calculated at 153 billion euro, but vulnerability to loss of
pollinators varies among geographical regions due, in part, to crop
specialization (Gallai et al. 2009). For example, West African countries
produce 56 per cent of the world's stimulant crops with a vulnerability to
pollinator loss of 90 per cent. The loss of pollination services in these crops
could have devastating effects on the economies of such countries in the
short term and lead to significant restructuring of global prices in the longer
term (Gallai et al. 2009).
Rate of vulnerability to pollinator loss and effect of pollinator loss on
global food production for pollinator-dependent crop categories based on
2005 data. IPEV, insect pollination economic value; EV, total production
economic value. Adapted from Gallai et al. (2009).
A crucial question is whether the loss of pollination services could
jeopardize world food supply. The overall production would keep pace with
consumption, but a complete loss of pollinators would cause global deficits in
fruits, vegetables and stimulants. Such declines in production could result in
significant market disruptions as well as nutrient deficiencies, even if total
caloric intake is still sufficient.
(c). Kuantitas dan Kualitas Air
The provision of sufficient quantities of clean water is an essential
ecological service provided to agroecosystems, and agriculture accounts for
about 70 per cent of global water use (FAO 2003). Perennial vegetation in
natural ecosystems such as forests can regulate the capture, infiltration,
retention and flow of water across the landscape. The plant community plays
26
a central role in regulating water flow by retaining soil, modifying soil structure
and producing litter. Forest soils tend to have a higher infiltration rate than
other soils, and forests tend to reduce peak flows and floods while
maintaining base flows (Maes et al. 2009). Through hydraulic lift and vertical
uplifting, deep rooting species can improve the availability of both water and
nutrients to other species in the ecosystem. In addition, soil erosion rates are
usually low, resulting in good water quality. Fast-growing plantation forests
may be an exception to this generalization, however; they can help regulate
groundwater recharge, but they may reduce stream flow and salinize or
acidify some soils (Jackson et al. 2005).
Water availability in agroecosystems depends not only on infiltration
and flow, but also on soil moisture retention, another type of ecosystem
service. While the supply of surface water and groundwater (‘blue water’)
inputs to agriculture through irrigation are indispensable in some parts of the
world, 80 per cent of agricultural water use comes from rainfall stored in soil
moisture (‘green water’; Molden 2007). Water storage in soil is regulated by
plant cover, soil organic matter and the soil biotic community (bacteria, fungi,
earthworms, etc.). Trapping of sediments and erosion are controlled by the
architecture of plants at or below the soil surface, the amount of surface litter
and litter decomposition rate. Invertebrates that move between the soil and
litter layer influence water movement within soil, as well as the relative
amounts of infiltration and runoff (Swift et al. 2004). These soil processes
provide essential ecosystem services to agriculture.
With climate change, increased variability of rainfall is predicted to
lead to greater risk of drought and flood, while higher temperatures will
increase water demand (IPCC 2007). Estimates of water availability for
agriculture often neglect the contribution of green water, but predictions about
water availability in 2050 are highly dependent on the inclusion of green
water. Whereas more than six billion people are predicted to experience
water shortages in 2050 when only blue water is taken into account, this
number drops to about four billion when both blue and green water availability
is taken into account (Rockström et al. 2009). Some regions of the world are
much more dependent on green water than others (Rockström et al. 2009).
On-farm management practices that target green water can
significantly alter these predictions of water shortages (Rost et al. 2009). For
example, modifying the tillage regime or mulching can reduce soil evaporation
by 35–50%. Rainwater harvest and on-farm storage in ponds, dykes or
subsurface dams can allow farmers to redirect water to crops during periods
of water stress, recovering up to 50 per cent of water normally lost to the
system. By incorporating moderate values (25%) for reductions in soil
evaporation and water harvesting into a dynamic global vegetation and water
balance model, Rost et al. (2009) predicted that global crop production could
be increased by nearly 20 per cent, a value comparable to the current
contribution of irrigation, from on-farm green water management practices.
True markets for water are rare (Mendelsohn & Olmstead 2009), and
the value of hydrological ecosystem services to agriculture is only partially
accounted for in most estimates. Most farmers who withdraw surface waters
directly do not pay for these services, except where local water sources are
controlled by irrigation districts. Agricultural water demand estimates are often
based on production data, where the marginal value of water is estimated by
the increase in profits from a unit increase in water inputs. Production data
can be highly variable, however, and increases in production can be difficult
27
to assign to water inputs (Mendelsohn & Olmstead 2009). Although market
approaches for direct water pricing are available, they tend to focus on blue
water in a particular water basin. Many water prices for agricultural use are
based on groundwater removal, using the energy costs of pumping as the key
input variable. The relatively new approach of payments for environmental
services has often focused on supporting watershed protection and water
quality enhancements that target the provision of blue water. It has been
suggested recently that farmers should receive payments or ‘green water
credits’ from downstream water users for good management practices that
enhance green water retention as well as blue water conservation.
Konsep Air-hijau
Green water was originally used as a synonym for soil moisture . More
precisely, green water is the portion of rainfall which is held in the soil and is
available for plants’ consumption, and then returns to the atmosphere through
the process of evapo-transpiration [8]. By contrast, blue water is the portion of
rainfall that enters into streams and lakes and also recharges groundwater
supplies.
Green water produces on-site benefits for crops and livestock, but the benefits
of blue water are mostly off-site as they are reaped downstream. When aiming to
increase off-site benefits through land use management, is important to address
the “water loss” function (green water) of land use rather than its “stream flow
regulation” (blue water) function. Once water is lost from a catchment through
evaporation, it is not possible for it to reappear in the stream flow. In contrast,
almost any impact of land use on stream flow regulation can be adjusted
through other interventions such as reservoirs or check dams.
One of the greatest challenges in water resources management that aims to
improve livelihoods is to find the most effective means to utilize green water.
Through the integration of land and rainwater resources management it is
possible to enhance the fraction of the rainwater that is potentially available as
soil moisture (and thus as green water) . There are three basic ways to achieve
this, and they are all promoted by proper land and vegetation management,
namely:
 Converting non-beneficial evaporation to beneficial transpiration by crops
through the minimisation of unproductive evaporation from moist surfaces
 Increasing the portion of rain which infiltrates the surface and forms vital
soil moisture through proper tillage and water management [9]
 Increasing the storage capacity of the soil through measures that alter soil
composition and structure
28
Globally, most of the precipitation (65 %) goes back into the atmosphere as vapour
through vegetation’s consumptive water use. Crop production accounts for about 10 %
of this consumptive water use, which amounts to almost twice as much in volume as all
the blue water that is withdrawn for different uses. Most of the remaining 90 % is
consumed by other terrestrial ecosystems, such as forests, grasslands and wetlands. It
should be noted that, on a global scale, forests are the largest consumers of water.
(Sumber: http://wiki.mekonginfo.org/index.php/125TA_Green_Water_Concept ….
Diunduh 7/7/2011)
(d). Struktur Tanah dan Kesuburan Tanah
Soil structure and fertility provide essential ecosystem services to
agroecosystems (Zhang et al. 2007). Well-aerated soils with abundant
organic matter are fundamental to nutrient acquisition by crops, as well as
water retention. Soil pore structure, soil aggregation and decomposition of
organic matter are influenced by the activities of bacteria, fungi and
macrofauna, such as earthworms, termites and other invertebrates. Microorganisms mediate nutrient availability through decomposition of detritus and
plant residues and through nitrogen fixation. Agricultural management
practices that degrade soil structure and soil microbial communities include
mechanical ploughing, disking, cultivating and harvesting, but management
practices can also protect the soil and reduce erosion and runoff.
Conservation tillage and other soil conservation measures can maintain soil
fertility by minimizing the loss of nutrients and keeping them available to
crops. Cover crops facilitate on-farm retention of soil and nutrients between
crop cycles, while hedgerows and riparian vegetation reduce erosion and
runoff among fields. Incorporation of crop residues can maintain soil organic
matter, which assists in water retention and nutrient provision to crops.
Together these practices conserve a suite of ecosystem services to
agriculture from the soil.
29
(e). Pengaruh bentang-lahan terhadap “pengiriman” jasa-jasa
ekosistem ke pertanian
The delivery of ecosystem services to agriculture is highly dependent
on the structure of the landscape in which the agroecosystem is embedded.
Agricultural landscapes span a continuum from structurally simple landscapes
dominated by one or two cropping systems to complex mosaics of diverse
cropping systems embedded in a natural habitat matrix. Water delivery to
agroecosystems depends on flow patterns across the landscape and can be
influenced by a variety of biophysical factors. Stream flow is influenced by
withdrawals for irrigation, as well as landscape simplification. Water
provisioning is also affected by diversion to other uses in the landscape or
watershed, such as domestic, industrial or energy consumption.
Both natural biological control services and pollination services
depend crucially on the movement of organisms across the agricultural
landscape, and hence the spatial structure of the landscape strongly
influences the magnitude of these ecological services to agricultural
ecosystems (Tscharntke et al. 2005; Kremen et al. 2007). In complex
landscapes, natural enemies and pollinators move among natural and seminatural habitats that provide them with refugia and resources that may be
scarce in crop fields (Coll 2009). Natural enemies with the ability to disperse
long distances or that have large home ranges are better able to survive in
disturbed agricultural landscapes with fewer or more distant patches of
natural habitat (Tscharntke et al. 2005).
Agricultural intensification can jeopardize many of the ecosystem
services provided by the landscape (Matson et al. 1997). Across large areas
of North America and Western Europe, agricultural intensification has resulted
in a simplification of landscape structure through the expansion of agricultural
land, increase in field size, loss of field margin vegetation and elimination of
natural habitat (Robinson & Sutherland 2002). This simplification tends to
lead to higher levels of pest damage and lower populations of natural
enemies (Brewer et al. 2008; Gardiner et al. 2009; O'Rourke 2010). A metaanalysis of the effects of landscape structure on natural enemies and pests in
agriculture showed that landscape complexity enhanced natural enemy
populations in 74 per cent of cases, whereas pest pressure was reduced in
more complex landscapes in 45 per cent of cases (Bianchi et al. 2006).
Natural enemies such as predators and parasitoids appear to respond to
landscape structure at smaller spatial scales than herbivorous insects
(Brewer et al. 2008; O'Rourke 2010) and may be more susceptible to habitat
fragmentation. Based on a review of 16 studies of nine crops on four
continents, Klein et al. (2007) concluded that agricultural intensification
threatens wild bee communities and hence may degrade their stabilizing
effect on pollination services at the landscape level. Recent studies have
suggested that farm-level diversification is more likely to influence pests and
natural enemies if the wider landscape is structurally simple, than if it is
already very complex (Tscharntke et al. 2005; O'Rourke 2010). In complex
landscapes, adding farm-level complexity does not necessarily enhance the
benefits of pest control services.
Agricultural intensification in the landscape can diminish other
ecosystem services as well. Protection of groundwater and surface water
quality can be threatened by intensification because of increased nutrients,
agrochemicals and dissolved salts (Dale & Polasky 2007). Loss of riparian
30
vegetation that often accompanies intensification can result in significant
sedimentation of waterways and dams. Other studies, however, have
suggested that initial conversion to agriculture can cause significant
reductions in ecosystem services, but subsequent intensification of the
system may not have large impacts (Steffan-Dewenter et al. 2007). Since the
quantification of intensification can be highly variable among studies and
agricultural systems, these results may not be incompatible. The bulk of
evidence indicates that increasing agricultural intensification will erode many
ecosystem services, and projections indicate that 80 per cent of crop
production growth in developing countries through to 2030 will come through
intensification (FAO 2006).
Not all agricultural landscapes are currently shaped by intensification.
Interestingly, changes in agricultural policies that encourage regional
specialization have led to intensification in some European landscapes,
accompanied by cropland abandonment in others (Stoate et al. 2009).
Widespread abandonment of agricultural land without restoration presents its
own set of problems, including landscape degradation, increased risk of
erosion and fire. In some areas, both agricultural intensification and land
abandonment coexist in the same landscapes, and both processes may
influence the delivery of ecosystem services to agroecosystems (Stoate et al.
2009).
8. Jasa-jasa Ecosystem dan Efek-merugikan dari Pertanian
Agroecosystems are essential sources of provisioning services, and
the value of the products they provide are readily measured using standard
market analysis. Depending on their structure and management, they may
also contribute a number of other ecosystem services (MEA 2005).
Ecosystem processes operating within agricultural systems can provide some
of the same supporting services described above, including pollination, pest
control, genetic diversity for future agricultural use, soil retention, and
regulation of soil fertility, nutrient cycling and water. In addition, agricultural
systems can be managed to support biodiversity and enhance carbon
sequestration—globally important ecosystem services.
(a). Efek negative pertanian terhadap Ekosistem
Agriculture can contribute to ecosystem services, but can also be a
source of disservices, including loss of biodiversity, agrochemical
contamination and sedimentation of waterways, pesticide poisoning of nontarget organisms, and emissions of greenhouse gases and pollutants (Dale &
Polasky 2007; Zhang et al. 2007). These disservices come at a significant
cost to humans, but there is often a mismatch between the benefits, which
accrue to the agricultural sector, and the costs, which are typically borne by
society at various scales, from local communities impacted by pesticides in
drinking water to the global commons affected by global warming. Linking
these disservices more closely to agricultural activities through incorporating
the externalities into the costs of production has the potential to reduce these
negative environmental consequences of agricultural practices.
31
(i). Siklus Hara dan Pencemaran
From the local scale to the global scale, agriculture has profound
effects on biogeochemical cycles and nutrient availability in ecosystems
(Vitousek et al. 1997; Galloway et al. 2004). The two nutrients that most limit
biological production in natural and agricultural ecosystems are nitrogen and
phosphorus, and they are also heavily applied in agroecosystems. Nitrogen
and phosphorus fertilizers have greatly increased the amount of new nitrogen
and phosphorus in the biosphere and have had complex, often harmful,
effects on natural ecosystems (Vitousek et al. 1997). These anthropogenically
mobilized nutrients have entered both groundwater and surface waters,
resulting in many negative consequences for human health and the
environment. Approximately 20 per cent of N fertilizer applied in agricultural
systems moves into aquatic ecosystems (Galloway et al. 2004). Impacts of
nutrient loss from agroecosystems include groundwater pollution and
increased nitrate levels in drinking water, eutrophication, increased frequency
and severity of algal blooms, hypoxia and fish kills, and ‘dead zones’ in
coastal marine ecosystems (Bouwman et al. 2009).
Ecosystem services within agroecosystems can be supported by
nutrient management strategies that recouple nitrogen, phosphorus and
carbon cycling within the agroecosystem. Under conventional practice in
developed countries, agroecosystems are often maintained in a state of
nutrient saturation and are inherently leaky as a result of chronic surplus
additions of nitrogen and phosphorus (Galloway et al. 2004; Drinkwater &
Snapp 2007; Vitousek et al. 2009). In developing countries, soils are more
likely to be depleted and nutrients may be much more limiting to production,
though chronic nutrient surpluses may still occur in some systems (table 2;
Vitousek et al. 2009).
Inputs and outputs of nitrogen and phosphorus in three corn cropping
systems with similar yield potential: a low-input corn-based system in western
Kenya; a highly fertilized wheat-corn double-cropping system in north China;
and a corn–soya bean rotation in IL, USA. Actual yields of corn were 2000,
8500 and 8200 kg ha−1 yr−1 per crop in the Kenya, China and USA systems,
respectively; the Chinese and USA systems also yielded wheat and soya
bean, respectively, in a separate cropping season. From Vitousek et al.
(2009).
To maintain ecosystem services, soil nutrient pools can be
intentionally managed to supply crops at the right time, while minimizing
nutrient losses by reducing soluble inorganic nitrogen and phosphorus pools
(Drinkwater & Snapp 2007). Practices such as cover cropping or
intercropping enhance plant and microbial assimilation of nitrogen and reduce
standing pools of nitrate, the form of nitrogen that is most susceptible to loss.
Other good management practices include diversifying nutrient sources,
legume intensification for biological nitrogen fixation and phosphorussolubilizing properties, and diversifying rotations. Integrated management of
biogeochemical processes that regulate the cycling of nutrients and carbon
could reduce the need for surplus nutrient additions in agriculture (Drinkwater
& Snapp 2007).
Recent analyses forecasting human alterations of soil nitrogen and
phosphorus cycling under various scenarios to 2050 further emphasize that
closing nutrient cycles in agroecosystems can significantly influence soil
nutrient balance (Bouwman et al. 2009). Spatially explicit modelling of soil
32
nitrogen and phosphorus balances suggest that soil phosphorus will be
depleted in grasslands around the world and rock phosphate reserves will be
reduced by 36–64% by 2100. Many scenarios indicate increases in soil
nitrogen over this period along with increased leaching and denitrification
losses, though nitrogen balances are likely to decline in North American and
Europe because of ongoing changes in management practices (Bouwman et
al. 2009).
Other ecosystem disservices from agriculture include applications of
pesticides that result in loss of biodiversity and pesticide residues in surface
and groundwater, which degrades the water provisioning services provided by
agroecosystems. Moreover, agriculture modifies the species identity and root
structure of the plant community, the production of litter, the extent and timing
of plant cover and the composition of the soil biotic community, all of which
influence water infiltration and retention in the soil. The intensity of agricultural
production and management practices affect both the quantity and quality of
water in an agricultural landscape. Practices that maximize plant cover, such
as minimum tillage, polycultures or agroforestry systems are likely to
decrease runoff and increase infiltration. Irrigation practices also influence
runoff, sedimentation and groundwater levels in the landscape.
(ii). Emisi Gas Rumah-Kaca
Agricultural activities are estimated to be responsible for 12–14% of
global anthropogenic emissions of greenhouse gases, not including
emissions that arise from land clearing (US-EPA 2006; IPCC 2007). After
fossil fuel combustion, land-use change is the second largest global cause of
CO2 emissions, and some of this change is driven by conversion to
agriculture, largely in developing countries. In developed countries, forest
conversion to cropland, pasture and rangeland were common through the
middle of the twentieth century, but current conversions are primarily for
suburban development. In addition to losses of above-ground carbon due to
deforestation or other land clearing, conversion of natural ecosystems to
agriculture reduces the soil carbon pool by 30–50% over 50–100 years in
temperate regions and 50–75% over 20–50 years in the tropics (Lal 2008a).
Although agricultural systems generate very large CO2 fluxes to and from the
atmosphere, the net flux appears to be small. However, both the magnitude of
emissions and the relative importance of the different sources vary widely
among agricultural systems around the world.
Agricultural activities contribute to emissions in several ways (table 3).
Approximately 49 per cent of global anthropogenic emissions of methane
(CH4) and 66 per cent of global annual emissions of nitrous oxide (N2O), both
greenhouse gases, are attributed to agriculture (FAO 2003), although there is
a wide range of uncertainty in the estimates of both the agricultural
contribution and the anthropogenic total. N2O emissions occur naturally as a
part of the soil nitrogen cycle, but the application of nitrogen to crops can
significantly increase the rate of emissions, particularly when more nitrogen is
applied than can be taken up by the plants. Nitrogen is added to soils through
the use of inorganic fertilizers, application of animal manure, cultivation of
nitrogen-fixing plants and retention of crop residues. Globally, approximately
50 per cent of N applied as fertilizer is taken up by the crop, 2–5% is stored
as soil N, 25 per cent is lost as N2O emissions and 20 per cent moves to
aquatic systems (Galloway et al. 2004). In addition to direct N2O emissions,
the production of synthetic nitrogen fertilizers is an energy-intensive process
33
that produces additional greenhouse gases. Flooded rice cultivation
contributes to greenhouse gas emissions through anaerobic decomposition of
soil organic matter by CH4-emitting soil microbes. The practice of burning
crop residues contributes to the production of both CH4 and N2O.
Agricultural contributions to global greenhouse gas emissions by
source and expected changes in agricultural greenhouse gas emissions by
2030. Adapted from FAO (2003).
Livestock production also contributes to CH4 and N2O emissions
(Pitesky et al. 2009), and these impacts are likely to increase through to 2050
as the demand for meat increases (FAO 2003). Ruminant livestock such as
cattle, sheep, goats and buffalo emit CH4 as a byproduct of their digestive
processes (enteric fermentation). Livestock waste can release both CH4,
through the biological breakdown of organic compounds, and N2O, through
microbial metabolism of nitrogen contained in manure. The magnitude of
direct emissions depends strongly on manure management practices, such
as the use of lagoons or field spreading, and to some degree on the type of
livestock feed. The magnitude of emissions attributed to livestock is
controversial, ranging from 3 to 18 per cent of global emissions, depending on
whether the effects of land-clearing (i.e. deforestation) for livestock production
is included in the estimate (Pitesky et al. 2009).
(b). Jasa-jasa Ekosistem dari Pertanian
On-farm management practices can significantly enhance the
ecosystem services provided by agriculture. Farmers routinely manage for
greater provisioning services by using inputs and practices to increase yields,
but management practices can also enhance other ecosystem services, such
as pollination, biological pest control, soil fertility and structure, water
regulation, and support for biodiversity. Habitat management within the
agroecosystem can provide the resources necessary for pollinators or natural
enemies (Tscharntke et al. 2005). Many studies have identified the important
role of perennial vegetation in supporting biodiversity in general and beneficial
organisms in particular (e.g. Perfecto & Vandermeer 2008). Evidence
suggests that management systems that emphasize crop diversity through
the use of polycultures, cover crops, crop rotations and agroforestry can often
reduce the abundance of insect pests that specialize on a particular crop,
while providing refuge and alternative prey for natural enemies (Andow 1991).
Similar practices may benefit wild pollinators, including minimal use of
pesticides, no-till systems and crop rotations with mass-flowering crops.
(i). Mitigasi Emisi Gas Rumah Kaca
Agricultural practices can effectively reduce or offset agricultural
greenhouse gas emissions through a variety of processes (Drinkwater &
Snapp 2007; Lal 2008a; Smith et al. 2008). Effective manure management
can significantly reduce emissions from animal waste. Replacing synthetic
nitrogen fertilizers with biological nitrogen fixation by legumes can reduce CO2
emissions from agricultural production by half (Drinkwater & Snapp 2007).
The process of perennialization and legume intensification in agroecosystems
modifies internal cycling processes and increases N use efficiency within
agroecosystems via the recoupling mechanisms discussed above. Chronic
surplus additions of inorganic N, which are currently commonplace, can be
reduced under these scenarios, leading to reductions in NOx and N2O
emissions.
34
Agriculture can offset greenhouse gas emissions by increasing the
capacity for carbon uptake and storage in soils, i.e. carbon sequestration (Lal
2008a,b). The net flux of CO2 between the land and the atmosphere is a
balance between carbon losses from land-use conversion and landmanagement practices, and carbon gains from plant growth and
sequestration of decomposed plant residues in soils. In particular, soil
conservation measures such as conservation tillage and no-till cultivation can
conserve soil carbon, and crop rotations and cover crops can reduce the
degradation of subsurface carbon. In general, water management and
erosion control can aid in maintaining soil organic carbon (Lal 2008a).
Soil carbon sequestration thus provides additional ecosystem services
to agriculture itself, by conserving soil structure and fertility, improving soil
quality, increasing the use efficiency of agronomic inputs, and improving
water quality by filtration and denaturing of pollutants (Lal 2008b; Smith et al.
2008). The economic benefits of conservation agriculture have been
estimated in diverse systems around the world, from smallholder agricultural
systems in Latin America and sub-Saharan Africa to large-scale commercial
production systems in Brazil and Canada (reviewed in Govaerts et al. 2009).
Many farmers have already adopted practices that retain soil C in order to
achieve higher productivity and lower costs. However, even the use of soil
conservation and restoration practices cannot fully restore soil carbon lost
through conversion to agriculture. It is estimated that the soil C pool attainable
through best management practices is typically 60–70% of the original soil C
pool prior to conversion (Lal 2008a).
Finally, agricultural land can also be used to grow crops for bioenergy
production. Bioenergy, particularly cellulosic biofuels, has the potential to
replace a portion of fossil fuels and to lower greenhouse gas emissions
(Smith et al. 2008). While burning fossil fuels adds carbon to the atmosphere,
bioenergy crops, if managed correctly, avoid this by recycling carbon.
Although carbon is released to the atmosphere when bioenergy feedstocks
are burned, carbon is recaptured during plant growth. The replacement of
fossil fuel-generated energy with solar energy captured by photosynthesis
has the potential to reduce CO2, N2O and NOx emissions.
However, calculating net emissions from bioenergy is tricky. First,
management practices used to grow crops and forages for bioenergy
production will influence net emissions. Development of appropriate
bioenergy systems based on perennial plant species that do not require
intensive inputs such as tillage, fertilizers and other agrochemicals have the
potential to help offset fossil fuel use in agriculture. Bioenergy systems that
rely on annual row crops such as corn are not likely to be as beneficial, and
expanding these systems can dramatically reduce the delivery of other
ecosystem services like biological pest control. Second, even with the use of
perennial species and few inputs, there is significant potential for higher,
rather than lower, emissions attributable to bioenergy crops, resulting from
land-use change as farmers respond to higher prices and convert forest and
grassland to new cropland. The production of bioenergy from waste products,
such as crop waste, fall grass harvests from reserve lands, or even municipal
waste, could avoid land-use change and result in lower CO2 emissions.
35
Agroekosistem Hutan sebagai sumber kayu bakar
SEORANG nenek menggendong potongan bambu kering yang ditebang
keluarganya di hutan rakyat lereng barat daya Gunung Merapi, DIY.
Masyarakat setempat rata-rata seminggu sekali mencari kayu bakar di
hutan rakyat dan hutan lindung Taman Nasional Gunung Merapi.
Mereka mengambil seperlunya untuk kepentingan dapur.
Sumber:
http://www.kabarindonesia.com/foto.php?jd=LOMBA+FOTO+YPH
L+MERAPI&pil=20081031200521 …. Diunduh 6/7/2011
36
9. Perspektif Agro-ekosistem
Lastly, it is important to emphasise that different stakeholders perceive
resource flows and uses differently. These differences can relate to
disciplinary expertise, gender, or stakeholder interests. The differences of
perspective lead to conflicts of interest; both between the members of an
interdisciplinary team (in terms of importance of certain aspects, or direction
of a study, for example), as well as between different stakeholders who want
to use the same resources in different ways.
Perspektif beragam disiplin diabstraksikan dalam karikatur berikut:
Sumber: ICRA (www.icra-edu.org) by Richard Hawkins, using material prepared for
ICRA by Clive Lightfoot.
Agroeistem perkebunan
Agroekosistem perkebunan rakyat dan perkebunan besar (estate)
yang dulu milik swasta asing dan sekarang kebanyakan perusahaan
negara, berkembang karena kebutuhan tanaman ekspor. Dimulai
dengan bahan-bahan ekspor seperti karet, kopi, teh dan coklat yang
merupakan hasil utama, sampai sekarang sistem perkebunan
berkembang dengan manajemen yang industri pertanian.
37
Agroekosistem perkebunan (Sumber:
http://bahesti.wordpress.com/2011/02/09/tugas-1-2/) …… diunduh 5/7/2011
Agroekosistem tegal pekarangan berkembang di lahan-lahan kering,
yang jauh dari sumber-sumber air yang cukup. Sistem ini diusahakan
orang setelah mereka menetap lama di wilayah itu, walupun demikian
tingkatan pengusahaannya rendah. Pengelolaan tegal pada umumnya
jarang menggunakan tenaga yang intensif, jarang ada yang
menggunakan tenaga hewan. Tanaman-tanaman yang diusahakan
terutama tanaman tanaman yang tahan kekeringan dan pohonpohonan.
38
Agroekosistem tegal pekarangan (Sumber:
http://bahesti.wordpress.com/2011/02/09/tugas-1-2/) …… diunduh 5/7/2011
Agroekosistem sawah
Sistem sawah, merupakan teknik budidaya yang tinggi, terutama
dalam pengolahan tanah dan pengelolaan air, sehingga tercapai
stabilitas biologi yang tinggi, sehingga kesuburan tanah dapat
dipertahankan. Ini dicapai dengan sistem pengairan yang sinambung
dan drainase yang baik. Sistem sawah merupakan potensi besar untuk
produksi pangan, baik padi maupun palawija. Di beberapa daerah,
pertanian tebu dan tembakau menggunakan sistem sawah.
39
Agroekosistem Sawah (Sumber: http://bahesti.wordpress.com/2011/02/09/tugas-12/) …… diunduh 5/7/2011
Agroekosistem Hutan Rakyat
Hutan rakyat adalah hutan yang dibangun dan dikelola oleh rakyat
yang biasanya berada di atas tanah milik atau tanah adat. Secara teknik,
hutan-hutan rakyat ini pada umumnya berbentuk wanatani; yakni campuran
antara pohon-pohonan dengan jenis-jenis tanaman bukan pohon. Baik
berupa wanatani sederhana, ataupun wanatani kompleks (agroforest) yang
sangat mirip strukturnya dengan hutan alam. Ada beberapa macam hutan
rakyat menurut status tanahnya. Di antaranya:
1. Hutan milik, yakni hutan rakyat yang dibangun di atas tanah-tanah
milik. Ini adalah model hutan rakyat yang paling umum, terutama di
Pulau Jawa. Luasnya bervariasi, mulai dari seperempat hektare
atau kurang, sampai sedemikian luas sehingga bisa menutupi
seluruh desa dan bahkan melebihinya.
2. Hutan adat, atau dalam bentuk lain: hutan desa, adalah hutanhutan rakyat yang dibangun di atas tanah komunal; biasanya juga
dikelola untuk tujuan-tujuan bersama atau untuk kepentingan
komunitas setempat.
3. Hutan kemasyarakatan (HKm), adalah hutan rakyat yang dibangun
di atas lahan-lahan milik negara, khususnya di atas kawasan hutan
negara. Dalam hal ini, hak pengelolaan atas bidang kawasan hutan
itu diberikan kepada sekelompok warga masyarakat; biasanya
berbentuk kelompok tani hutan atau koperasi. Model HKm jarang
disebut sebagai hutan rakyat, dan umumnya dianggap terpisah.
40
Agroekosistem hutan rakyat (Sumber:
http://mitratradinghutanrakyat.blogspot.com/2010/04/hutan-rakyat.html ..... diunduh
6/7/2011)
Agroekosistem Kebun Pepaya
Tanaman papaya dapat tumbuh pada dataran rendah dan tinggi 700 1000 mdpl, curah hujan 1000 - 2000 mm/tahun, suhu udara optimum 22 - 26
derajat C dan kelembaban udara sekitar 40% dan angin yang tidak terlalu
kencang sangat baik untuk penyerbukan. Tanah subur, gembur, mengandung
humus dan harus banyak menahan air, pH tanah yang ideal adalah netral
dengan pH 6 -7.
Kebun pepaya jenis kalifornia yang menerapkan teknologi pertanian
organik dengan ditanami 8.000 (delapan ribu) pohon setiap hektar, dan akan
semakin bertambah seiring dengan perluasan lahan pepaya kalifornia organik
ini dan mengingat masih banyak area kebun yang masih kosong yang saat ini
sedang diolah. Berdasarkan estimasi produktifitas, satu pohon setidaknya
bisa menghasilkan 1 buah (sekitar 1 kg). Jadi dalam sekali panen,
produktifitas pepaya kalifornia organik kami setidaknya bisa mencapai 8 ton
per minggu. atau 32 ton per bulan. Tidak hanya mempunyai produktifitas
tinggi, pepaya kalifornia organik ini juga sangat berkualitas dan mempunyai
rasa terbaik. Apalagi jika dibandingkan rasa pepaya thailand atau negara lain,
pepaya kalifornia asal indonesia merupakan yang terbaik dalam hal rasa.
41
Agroekosistem kebun papaya (umur muda0 (Sumber:
http://bumiganesa.com/?p=520 …. Diunduh 6/7/2011)
42
KEBUN PEPAYA CALIFORNIA, Umur tanaman 1 tahun. CITRA KARYA TANI.
Jl.Raya Cipaku No.34 Bogor. Aji 085888228417.
email : windi_ckt@yahoo.com
Facebook : Ajie win
Agroekosistem Tambak Ikan
Tambak dalam perikanan adalah kolam buatan, biasanya di
daerah pantai, yang diisi air dan dimanfaatkan sebagai sarana
budidaya perairan (akuakultur). Hewan yang dibudidayakan adalah
hewan air, terutama ikan, udang, serta kerang. Penyebutan "tambak"
ini biasanya dihubungkan dengan air payau atau air laut. Kolam yang
berisi air tawar biasanya disebut kolam saja atau empang.
43
Agroekosistem Tambak Ikan dan Kepiting di Bone (Sumber:
http://www.flickr.com/photos/fadla/3397849067/ ….. diunduh 6/7/2011)
Agroekosistem Tambak-Mangrove
Mengingat sangat pentingnya fungsi hutan mangrove disatu sisi dan
banyaknya pembukaan areal hutan mangrove menjadi kawasan
pertambakan di pesisir Delta Mahakam pada sisi lain maka perlu
segera dilakukan upaya-upaya pemulihan kembali fungsi ekologis dan
ekonomi kawasan hutan mangrove di Delta Mahakam melalui
kegiatan rehabilitasi lahan yang di kombinasikan dengan
pengembangan budidaya tambak yang disebut tambak sivofishery,
sehingga kegiatan ektensifikasi tambak yang merusak lingkungan
dapat digantikan dengan model tambak sivofishery. Penerapan
tambak silvofishery telah di terapkan di Handil 8 Kelurahan Muara
Jawa Ilir Kecamatan Muara Jawa Kawasan Delta Mahakam,
merupakan daerah yang sebagian besar wilayahnya terdiri dari
perairan pesisir dan laut, memiliki potensi besar dalam bidang
perikanan, pariwisata, kawasan hutan mangrove dan sumberdaya
alam lainnya. Sumberdaya perikanan yang memiliki potensi dan
memiliki nilai ekonomis penting serta merupakan komoditas ekspor di
daerah tersebut salah satunya adalah kepiting bakau. Tambak
silvofishery di daerah handil 8 saat ini digunakan untuk budidaya
kepiting soka (Soft Shell Crabs) dari jenis Kepiting bakau (Scylla
serrata F).
44
Budidaya kepiting soka pada tambak silvofishery (Sumber:
http://rizalfishery.blogspot.com/2009/05/mangrove-dan-tambak.html .....
diunduh 6/7/2011)
Agroekosistems dan Sistem Teknologi Pertanian
It is necessary to start with some definitions, including the distinction
between agroecosystems and agricultural technology systems. An
agroecosystem is a complex of air, water, soil, plants, animals, microorganisms, and everything else in a bounded area that people have
modified for the purposes of agricultural production. An agroecosystem
can be of any specified size. It can be a single field, it can be a household
farm, or it can be the agricultural landscape of a village, region, or nation.
An agricultural technology system is the blueprint for an agroecosystem.
It is a 'design', 'plan', or 'mental image' - the total package of technology
which a farmer or community uses to mold a given area into an
agroecosystem. An agricultural technology system specifies all the crops
(and/or livestock) to be employed, the spatial arrangement and temporal
sequence of the crops, and all inputs to modify the environment so crops
produce as they should. Agricultural technology systems embrace all that
is customarily included in the concept of cropping systems, but
agricultural technology systems are broader in the sense that they include
everything that is done to shape an agroecosystem, including parts of the
ecosystem that are not directly related to the crops.
45
Beberapa konsep dasar untuk penilaian agroekosistem.(Sumber:
http://www.gerrymarten.com/publicatons/agroecosystem-Assessment.html .....
diunduh 3/7/2011)
Agricultural technology systems are important to farmers as their point of
departure for molding the agroecosystems in which they work, but the
technology systems are particularly important to agricultural scientists.
When scientists try to improve agriculture, they are seeking better designs
for technology systems, and it is through technology systems that
scientists communicate the fruits of their efforts to farmers. (The
'technology' can be any form of agricultural knowledge, including
traditional and informal knowledge as well as technology associated with
modern science.)
Agricultural technology systems can be at any level of generality. For
example, 'shifting cultivation' specifies a broad array of agricultural
technologies, while the technology system for a mixture of maize and
beans, explicitly designed for particular soil conditions at a particular
location and season of the year, may be highly specific with regard to
crop variety and cultivation practices. As a rule, a more general
technology system applies to a broader geographic area, or a broader
range of environmental and social conditions, while a specific technology
system applies to a particular locality.
Agricultural technology systems are applied to specific pieces of
landscape under specific environmental and social conditions to form
real-world agroecosystems. Just as the structure of a house is a
consequence of not only an architect's blueprint, but also the particular
site on which it is built, the specific materials available for construction,
and the carpenter's skills and personal style with regard to details of
construction, the same applies to agroecosystems.
The structure of an agroecosystem is a consequence of not only its
agricultural blueprint (i.e. the agricultural technology system) but also:
1. its environmental setting (e.g. climate, soil, topography, various
organisms in the area), which defines the material resources available
for making an agroecosystem;
2. the farmers and their social setting (e.g. human values, institutions
and skills), which conditions how people interact with one another
and the ecosystem in which they live, thereby determining how
46
people actually apply their technology to mold the environment into
an agroecosystem.
Within many rural communities, there are gender differences in resource
perception and use. An example is given here, from Bumbaozio, Northern
Ghana, where men and women were each (separately) asked to map their
agro-ecological resources :
The women’s’ group indicated that the agroecological resources of
importance to
them were:
1. the shea nut trees and raffia palms they use for cooking and income
generation, especially in the case of weaving raffia;
2. the stream that supplies water for the household; and
3. the black soils that the women use for plastering walls.
Masyarakat kaum pria di Bumbaozio berpendapat bahwa sumberdaya
agro-ekologis yang sangat penting baginya adalah areal lahan yang
mempunyai tanah spesifik untuk menanam jenis-jenis tanaman terentu.
Pandangan ini setara dengan konsep “pekarangan:”
Lahan pekarangan adalah sebidang lahan yang terletak langsung di
sekitar rumah tinggal dan jelas batas-batasannya, ditanami dengan satu atau
berbagai jenis tanaman dan masih mempunyai hubungan pemilikan dan/atau
fungsional dengan rumah yang bersangkutan. Hubungan fungsional yang
dimaksudkan di sini adalah meliputi hubungan sosial budaya, hubungan
ekonomi, serta hubungan biofisika. Pekarangan merupakan areal tanah yang
berdekatan dengan sebuah bangunan. Tanah ini dapat diplester, di pakai
untuk berkebun, ditanami bunga atau kadang-kadang memiliki kolam.
Pekarangan bisa terdapat di depan, belakang atau samping bangunan
tergantung seberapa besar sisa tanah yang tersedia setelah dipakai untuk
bangunan utamanya. Walaupun dalam luasan yang kecil, pekarangan dapat
dijadikan sebagai tinjauan dalam mengelola lingkungan yang dinilai
berdasarkan keanekaragaman dalam pekarangan tersebut. Misalnya,
pemeliharaan tanaman berbuah, tumbuhan berkayu maupun pemeliharaan
ternak seperti ayam, itik, dan lainnya.
Lahan pekarangan beserta isinya merupakan satu kesatuan
kehidupan yang saling menguntungkan. Sebagian dari tanaman
dimanfaatkan untuk pakan ternak, dan sebagian lagi untuk manusia,
sedangkan kotoran ternak digunakan sebagai pupuk kandang untuk
menyuburkan tanah pekarangan. Dengan demikian, hubungan antara tanah,
tanaman, hewan peliharaan, ikan dan manusia sebagai unit-unit di
pekarangan yang merupakan satu kesatuan terpadu
47
Sumber: ICRA (www.icra-edu.org) by Richard Hawkins, using material prepared for
ICRA by Clive Lightfoot.
Because men’s interests surround the control and management of land their
maps differed from that of the women whose interests lay mainly in plant
species. The women’s map is a long way from a ‘conventional’ map and to
outsiders these maps are difficult to understand. And even though the men’s
and women’s maps were very different, the men and women understood each
others ‘maps’ immediately. While the men where explaining their map to the
assembled participants it became evident to the women present that the men
were talking about expanding their cassava planting into an area of raffia
palms. This area where women where collecting raffia for basket weaving. In
a very real and practical way the exposure of this potential conflict
demonstrated to all the value of each putting their perceptions down on paper
(Source: Noble, 1995)
48
Sumber: ICRA (www.icra-edu.org) by Richard Hawkins, using material prepared for
ICRA by Clive Lightfoot.
Agroekosistem Pekarangan
Pekarangan merupakan areal tanah yang biasanya berdekatan
dengan sebuah bangunan. Tanah ini dapat diplester, dipakai untuk berkebun,
ditanami bunga, atau kadang-kadang memiliki kolam. Pekarangan bisa
berada di depan, belakang atau samping sebuah bangunan, tergantung
seberapa besar sisa tanah yang tersedia setelah dipakai untuk bangunan
utamanya. Menurut arti katanya, pekarangan berasal ari kata “karang” yang
berarti halaman rumah (Poerwodarminto, 1976). Sedang secara luas, Terra
(1948) memberikan batasan pengertian sebagai berikut:
“Pekarangan adalah tanah di sekitar perumahan, kebanyakan
berpagar keliling, dan biasanya ditanami padat dengan beraneka
macam tanaman semusim maupun tanaman tahunan untuk keperluan
sendiri sehari-hari dan untuk diperdangkan. Pekarangan kebanyakan
slng berdekaan, dan besama-sama membentuk kampung, dukuh,
atau desa”.
Batasan pengertian ini, di dalam praktek masih terus dipergunakan
sampai sekitar dua puluh tahun kemudian. Terbukti dari tulisan-tlisan
Soeparma (1969), maupun Danoesastro (1973), masih juga menggunakan
definisi tersebut. Baru setelah Soemarwoto (1975) yang melihatnya sebagai
suatu ekosistem, berhasil memberikan definisi yang lebih lengkap dengan
mengatakan bahwa:
“Pekarangan adalah sebidang tanah darat yang terletak langsung di
sekitar rumah tinggal dan jelas batas-batasannya, ditanami dengan
satu atau berbagai jenis tanaman dan masih mempunyai hubungan
49
pemilikan dan/atau fungsional dengan rumah yang bersangkutan.
Hubungan fungsional yang dimaksudkan di sini adalah meliputi
hubungan sosial budaya, hubungan ekonomi, serta hubungan
biofisika”. (Danoesastro, 1978).
Fungsi Sosial Budaya Lahan Pekarangan
Ditinjau dari segi sosial budaya, dewasa ini nampak ada
kecenderungan bahwa pekarangan dipandang tidak lebih jauh dari fungsi
estetikanya saja. Pandangan seperti ini nampak pada beberapa anggota
masyarakat pedesaan yang elah “maju”, terlebih pada masyarakat perkotaan.
Misalnya dengan memenuhi pekarangannya dengan tanaman hias dengan
dikelilingi tembok atau pagar besi dengan gaya arsitektur “modern”. Namun
demikian, bagi masyarakat pedesaan yang masih “murni”, justru masih
banyak didapati pekarangan yang tidak berpagar sama sekali. Kalaupun
berpagar, selalu ada bagian yang masih terbuka atau diberi pintu yang
mudah dibuka oleh siapapun dengan maksud untuk tetap memberi
keleluasaan bagi masyarakat umum untuk keluar masuk pekarangannya.
Nampaknya, bagi masyarakat desa, pekarangan juga mempunyai
fungsi sebagai jalan umum (lurung) antar tetangga, atar kampung, antar
dukuh, bahkan antar desa satu dengan yang lainnya. Di samping itu, pada
setiap pekarangan terdapat ”pelataran” (Jawa) atau “buruan” (Sunda) yang
dapat dipergunakan sebagai tempat bemain anak-anak sekampung. Adanya
kolam tempat mandi atau sumur di dalam pekarangan, juga dapat
dipergunakan oleh orang-orang sekampung dengan bebas bahkan sekaligus
merupakan tempat pertemuan mereka sebagai sarana komunikasi masa
(Soemarwoto, 1978).
Dengan demikian, bagi masyarakat desa yang asli, pekarangan
bukanlah milik pribadi yang”eksklusif”, melainkan juga mempunai fungsi
sosial budaya di mana anggota masyarakat (termasuk anak-anak) dapat
bebas mempergunakannya untuk keperluan-keperluan yang bersifat sosial
kebudayaan pula.
Fungsi ekonomi Lahan Pekarangan
Selain fungsi hubungan sosial budaya, pekarangan juga memiliki
fungsi hubungan ekonomi yang tidak kecil artinya bagi masyarakat yang
hidup di pedesaan. Dari hasil survey pemanfaatan pekarangan di Kalasan,
disimpulkan oleh Danoesastro (1978), sedikitnya ada empat fungsi pokok
yang dipunyai pekarangan, yaitu: sebagai sumber bahan makanan, sebagai
penhasil tanaman perdagangan, sebagai penghasl tanaman rempah-rempah
atau obat-obatan, dan juga sumber bebagai macam kayu-kayuan (untuk kayu
nakar, bahan bangunan, maupun bahan kerajinan).
Tabel 1. Daftar berbagai macam tanaman di pekarangan petani di
kelurahan Sampel, dikelompokkan menurut fungsina
(Kecamatan Kalasan).
No. Golongan Tanaman
Macam Tanamannya
I
Sumber
bahan
makanan
tambahan :
Ubikayu, ganyong, uwi, gembolo,
1. Tanaman karbohdrat
tales,garut dll.
Mlinjo, koro, nangka, pete.
2. Tanaman sayuran
Pepaya, salak, mangga, jeruk,
50
3. Buah-buahan
II
III
IV
4. Lain-lain
Tanaman perdagangan
Rempah-rempah, obat-obatan.
Kayu-kayuan:
1. Kayu bakar
2. Bahan bangunan
3. Bahan kerajinan
Sumber: Danoesastro, 1978.
duku, jambu, pakel, mundu, dll.
Sirih.
Kelapa, cengkeh, rambutan.
Jahe, laos, kunir, kencur, dll.
Munggur, mahoni, lmtoro.
Jati, sono, bambu, wadang.
Bambu, pandan, dll.
Berdasarkan kenyataan-kenyataan tersebutlah, maka Danoesastro
(1977) sampai pada kesimpulan bahwa bagi masyarakat pedesaan,
pekarangan dapat dipandang sebagai “lumbung hidup” yang tiap tahun
diperlukan untuk mengatasi paceklik, dan sekaligus juga merupakan “terugval
basis” atau pangkalan induk yang sewaktu-waktu dapat dimabil manfaatnya
apabila usahatani di sawah atau tegalan mengalami bencana atau kegagalan
akibat serangan hama/penyakit, banjir, kekeringan dan bencana alam yang
lain.
Fungsi biofisika Lahan Pekarangan
Pada pandangan pertama, bagi orang “kota” yang baru pertama kali
turun masuk desa, akan nampak olehnya sistem pekarangan yang ditanami
secara acak-acakan dengan segala macam jenis tanaman dan sering pula
menimbukan kesan “menjijikkan” karena adanya kotoran hewan ternak di
sana sini. Namun, dalam penelitian menunjukkan, bahwa keadaan serupa itu
adalah merupakan manifestasi kemanunggalan manusia dengan
lingkungannya sebagaimana yang telah diajarkan nenek moyangnya. Di
daerah Sunda misalnya, terdapat pandangan bahwa :
“Manusia adalah bagian dalam dan dari satu kesatuan yang besar
..........Semua mempunai tempatnya sendiri dari tidak ada sesuatu
yang berdiri sendiri.....
Dalam teori kebatinan Jawa, disebutkan bahwa sesuatu yang ada dan yang hidup
pada pokoknya satu dan tunggal. Bahkan, justru pola pengusahaan pekarangan
seperti itulah ternyata, yang secara alamiah diakui sebagi persyaratan demi
berlangsungnya proses daur ulang (recycling) secara natural (alami) yang paling
efektif dan efisien, sehingga pada kehidupan masyarakat desa tidak mengenal zat
buangan. Apa yang menjadi zat buangan dari suatu proses, merupakan
sumberdaya yang dipergunakan dalam proses berikutnya yang lain. Sebagai
contoh, segala macam sampah dan kotoran ternak dikumpulkan menjadi
kompos untuk pupuk tanaman. Sisa dapur, sisa-sisa makanan, kotoran manusia
dan ternak dibuang ke kolam untuk dimakan ikan. Ikan dan hasil tanaman (daun,
bunga, atau buahnya) dimakan manusia, kotoran manusia dan sampah dibuang
ke kolam atau untuk kompos, demikian seterusnya tanpa berhenti dan berulangulang.
Dengan demikian kalaupun dalam proses kemajuan peradaban
manusia ada sesuatu yang perlu diperbaki seperti: pembuatan jamban
keluarga di atas kolam, sistem daur ulang yang tidak baik dan efisiensi harus
tetap terjaga kelangsungannya.
51
Lahan pekarangan digunakan untuk menanam aneka jenis tanaman yang memnghasilkan
bahan pangan bagi rumahtangga (Sumber: http://jakartacity.olx.co.id/dijual-tanahpekarangan-iid-185797961 ..... diunduh 6/7/2011)
52
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