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AGRO-ECOLOGICAL ANALYSIS FOR AGRICULTURALDEVELOPMENT IN INDONESIA

Istiqlal AmienCenter for Soil and Agroclimate Research

Jalan Juanda 98Bogor 16123, Indonesia

ABSTRACT

Current land allocation in Indonesia is unlikely to support sustainable utilization, neither is itable to adjust to a changing global economy. Using advanced analytical methods, the availableinformation on land resources now can be properly utilized to reevaluate appropriate agriculturalland use. An agroecological approach, using a minimum data set covering terrain, soil andclimate, can delineate land resources for sustainable utilization such as annual crops, agroforestry,perennial crops and forests. This approach was employed in land resource analysis for Java,Sumatra, Kalimantan, and Sulawesi. The results indicate that in Sumatra, Kalimantan, and partsof Sulawesi, substantial areas of land that are suitable for agriculture are currently utilized forforestry. In Java and parts of Sulawesi, on the other hand, lands that should be forested iscultivated. Using an expert system as a decision support tool, appropriate production systems aswell as crop choices for a particular region can be assessed. Agricultural land can be dividedinto three categories, used respectively for agricultural intensification, expansion, and rehabilitationthrough diversification programs.

Keywords: agroecology, dissemination, diversification, expansion, expert system, Indonesia,intensification, rehabilitation, sustainable land use

INTRODUCTION

Although Indonesia has had a high rateof growth in industry and services during thelast few decades, over half the population isstill living in rural areas. The increasingagricultural population and the reducedeconomic growth rate in recent years has beenputting considerable pressure on arable land.Much of the land has become degradedbecause of misuse and over-exploitation.Unless this trend can be reversed, renewableresources and their sustainable utilization arein jeopardy.

Current land allocation is mainly acontinuation of what was established by thecolonial Dutch East India Company, and isunlikely to conform with sustainable land use.When Europe was the main destination ofIndonesian agricultural exports, it was logicalto utilize land in coastal areas close to

harbors, unless the crop required the coolerclimate of the highlands. As populationsincreased, farmers were forced into uplandareas. With the monsoon rainfall pattern ofthe tropics, this type of land is disrupting thewater cycle, and already causing frequentfloods and droughts.

Neither will small-scale subsistencefarming be able to adjust to the changingglobal economy. Trade and transportationcosts in some countries overseas are so lowthat it is often more profitable to importagricultural goods than to produce themourselves. The agricultural produce of small-scale farmers has neither the required quantitynor the quality to meet international marketdemand.

The analysis of renewable naturalresources should be carried out in steps. Thefirst is upstream analysis, that deals mainlywith land allocation. The second is

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downstream analysis, which is mainlyconcerned with land management for allocateduses. Land allocation, in the form ofselecting appropriate production systems andcrops, is urgently needed. This will not onlyhelp farmers in Indonesia to face the comingfree trade, but will promote trade betweendifferent parts of the country while minimizingcompetition and market surpluses, thuspromoting national integration.

Whether crops are suitable for aparticular area, or whether technology can betransferred between areas, can be assessedonly if there is enough information concerningthe requirements of the crop and the nature ofthe local agroecological conditions.Information about terrain, soil, hydrology andclimate has been collected for many parts ofIndonesia. However, the use of these data inmaking decisions about agriculturaldevelopment is very limited.

Information about land resources isavailable in many government institutions,although it varies as to the level of detail andaccuracy. This information should be utilizedin a more systematic and practical way byadvanced analytical methods. Definingagroecological zones on the basis of terrain,soil, hydrology and climate facilitates cropselection and agrotechnology transfer. Thisapproach can also improve the efficiency ofresearch and the potential impact oftechnologies generated by research.

RENEWABLE RESOURCESAND ANALYSIS STRATEGY

The dynamic of resources and hierarchyof management domain

Renewable natural resources that directlyaffect agriculture can be roughly dividedaccording to their relative stability. The moststable are terrain and soil, which probably willnot change much within our lifetime, followedby aerial resources. In the field ofagriculture, the dominant aerial variable willbe climate. Although weather may changedynamically over a month or a season,climatic change will occur over a longerperiod, probably within a time frame of 30 to50 years. Biological resources such as plants,microbes and animals are more dynamic. Inthe case of plant pests and diseases,

populations often flucturate seasonally,depending on the availability of food. Themost dynamic resource is human beings, whocan move freely at any time.

Because some resources are dynamic andsome are stable, inventory characterization,delineation and analysis must be carried out ina systematic way. Natural characteristics suchas climate, terrain and soil should be put onone map. They must be distinguished fromman-made features, which can change in arelatively short time. These include land use(such as the interaction between soil, plantsand human beings) and infrastructure (such asroads, bridges and ports) that can be built orchange within a year. Otherwise, we mayhave to prepare a new map every few years.With the development of computer technologysuch as geographic information systems (GIS),this information now can be put into differentlayers that can easily be lain one on top ofanother for analysis.

The ability of plants to convert solarenergy, water and nutrients by photosynthesisinto starches, sugars, fiber etc. is determinedby the environment. The agroecologicalapproach can accurately delineate the conditionof this environment, and select a sustainableagriculture that is technically sound,economically feasible and environmentallysafe. The agroecological approach sets a two-level hierarchy in resource management, eachwith different inputs and outputs. The first isfor national level planning, with an expectedoutput of production systems and cropchoices. This level is related to resourceallocation, and should be the first activity tobe carried out. The end users of this outputwill be policy makers and planners.

Terrain information is the main factor indetermining production systems. Fragile landswith steep slopes and marginal soils must bekept covered with natural vegetation. Themain climatic information required is moistureand temperature regimes, to assess the bestcrop choices. The main soil information thatlimits agriculture is texture, acidity anddrainage. These data can be obtained fromfield surveys.

For the second hierarchy, theagroecological approach is expected to provideinformation on crop management. Thisincludes the selection of cultivars, croppingpattern and time of planting, as well as soil

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management, including fertilization andirrigation. Information about soil and climateis required to analyzed the expected outputs(Table 1). If more detailed information isavailable, crop yield can be predicted and aneconomic analysis for particular crop and soilmanagement can be carried out. Analysis ofthis kind needs information on the cost ofproduction and the market value of theproduce under different market conditions.

Climate and land resources as criteriain agroecological zoning

Traditionally, land resource surveys haveplaced much more emphasis on soil than onclimate. Consequently, climate resourceinventories are seldom associated with soilinformation. However, climate and soil areclosely related. Climate is an important factorin soil formation. Because soil formation is along-term process, general climatic informationon an annual basis is adequate.

However, a more detailed information isrequired in order to assess whether particularcrops are suited to a particular climate.Monthly data over a period of 20 - 30 yearsare not generally considered sufficient. Topredict crop performance at the field level,daily weather data are required. The time ofplanting strongly affects the performance andyield of annual crops. The weather variablesmost affecting crop growth are rainfall,maximum and minimum temperatures, andsolar radiation. These data can be used inthe simulation of dynamic plant growthprocesses such as photosynthesis andrespiration.

Weather and climate information that islimited in quantity and poor in quality needsto be enriched to make it usable at thedetailed planning level. Many soil surveys ona semi-detailed or detailed scale provide onlygeneral climatic information. Such limitedinformation allows only crop suitability ratings,not the detailed modelling of cropperformance. If such survey results weresupplemented with adequate weatherinformation, they could provide better insightsinto plant management options such ascropping and time of planting, as well as soilmanagement options such as fertilizer inputsor the need for irrigation.

Technology recommendations appropriate

at the field level can only be made if thedecision-making processes of farmers, and thelimits imposed on them by the availability ofproduction resources, are well understood. Aspart of this understanding, the availability of aresource inventory covering both soil andclimate is imperative. The Center for Soiland Agoclimate Research, established in 1905,has conducted many soil surveys, but only in1986 did it begin to develop a soil database.This soil information is being linked to ageographic information system for easyretrieval, and for updating as more recent dataare obtained. At the present moment, thedatabase contains only land resources data forSumatra on a reconnaissance scale. It will bean enormous task to computerize the landresource data obtained from surveys in otherareas, in addition to the storage of data fromon-going and future surveys.

APPROPRIATE LAND ALLOCATION FORSUSTAINABLE DEVELOPMENT

Production systems

Sustainable agriculture can be attainedonly when land is used in a proper way.When land is utilized improperly, productivityrapidly falls and the ecosystem is jeopardized.Proper land use ensures that resources can beused for future generations. Integrated landuse management should be directed at anoptimal, sustainable use of natural resources.This may include regulation of hydrology,climate stabilization, and preservation ofbiodiversity such as gene pools, wild-life andplant habitats, as well as appropriate researchand education.

Proper land utilization improvesefficiency in the production process, becauserelatively few inputs are required to attain thedesired output, thus making production moreprofitable. Forest or permanent tree cropsprovide natural land cover in the upperwatershed. In coastal regions, mangroveforests should also be conserved to protect thecoast from erosion. In cold or dry areas,forests do not have the diversity of thosefound in warm humid areas. There is agrowing awareness that native vegetation _

savanna, shrubs and trees _ needs to beconserved.

Gradient is a critical factor, because

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erosion and soil degradation are a real threatto agriculture in hilly regions. Steep slopesalso limit the use of agricultural machineryand draft animals for soil tillage. In suchareas, therefore, it is usual to grow perennialcrops such as trees or pasture.

Energy efficiency also needs to beconsidered. On farms in steep slopelands, thelabor required to transport agricultural inputsto the farm, and produce to market, may bevery expensive. Labor-intensive agriculture onsloping lands is unlikely to be feasible iflabor costs are relatively high.

High-value horticultural crops such astemperate flowers and vegetables are oftencultivated on terraced fields in mountainousregions, to take advantage of the coolertemperatures at high altitudes. However,terracing is not feasible on all soils. Soilsformed from loose parent material such assandstone are vulnerable to landslides whenterraced. Terracing highly weathered acidtropical soils will expose the high-aluminum,infertile subsoil and reduce cropping options.

If the soil is suitable, annual cropagriculture is recommended when the slope is8% or less. It is recommended on suchslopes when soils are formed from quartzsand or deep peat, or are high in gravel orstones, making soil tillage difficult. Soil withgrey clay close to the surface can bereclaimed only when reduced conditions canbe maintained, as when it is used to growpaddy rice. Otherwise, it should be left in itsnatural state and used to grow useful treessuch as tea-tree (Melaleuca leucadendra).Land with a gradient of 8 - 15% isrecommended for agroforesty, in which annualcrops are cultivated along with perennial trees.Land with a gradient of 15 - 40% should beused only for perennial crops such as fruittrees, plantations, or forest.

Selection and management of annualcrops

Selection of suitable crops for specificlocations is based on slope, soil texture andacidity, as well as on moisture andtemperature regimes. Crops that are suited toa set of environmental conditions requirefewer inputs than those which are lesssuitable. Unsuitable crops will give loweryields of poorer quality. In the long run,

such land use may not be economicallyfeasible.

Crop growth is generally constrained byan excess or shortage of water, and byextreme temperatures. Soil constraints areusually easier and less expensive to alleviatethan those of climate and moisture.Temperature and moisture regimes can becombined to classify the environmentaccording to which crops are suitable(Eswaran 1984).

In the production of annual crops,suitable crops and cropping patterns aredetermined by the water supply, based on thenumber of wet months i.e., those in whichrainfall exceeds evapotranspiration and otherlosses. Crop selection should includeperennial crops and hedgerows used in alleycropping, and the grasses and legumes used ascover crops and for terrace stabilization. Intropical or subtropical zones with sufficientrainfall, at least three crops can usually begrown each year.

Because rice is the staple food in Asia,it should be grown at the beginning of therainy season. The rice plants may beintercropped with maize and cassava. Afterharvest, a more drought-tolerant crop such ascowpea should be planted, to avoid cropfailure in the case of drought. At the end ofthe dry season, cassava can be harvested toimprove soil aeration and as an alternativemeans of soil tillage for the next crop.

Areas with limited moisture and noirrigation can usually be cropped at leasttwice a year. Rice and maize arerecommended early in the rainy season,followed by secondary crops, particularly grainlegumes. Grain legume crops for soilswithout acidity problems are normally soybeanor mungbean, but peanut or cowpea aregenerally grown in acid soils. Peanut requirescalcium, particularly during pod filling.Calcium levels are usually low in acid soils,but because it is needed as a fertilizer, ratherthan a soil conditioner, small amounts ofeither lime or gypsum are adequate.

In semi-arid moisture regimes, rainoccurs in only a few months each year andonly one crop is possible. For such areas,short-duration, drought-tolerant crops such assorghum or some cultivars of maize arerecommended, and also pigeon-pea (annual orperennia). The deep-rooted pigeon-pea can

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extract water from the relatively moist subsoilduring the dry season. Some legume forage cropssuch as Stylosanthes are also drought tolerant.

LAND MANAGEMENT FOR SPECIFIC USES

Soil management

Clay minerals play a key role indetermining the capacity of a soil to retainnutrients and moisture. They are therefore ofgreat importance in fertilization and irrigationmanagement.

For this reason, recommendations on thetype of fertilizers and the method ofapplication for a particular crop are based toa large extent on soil clay mineralogy. Thefate of phosphate and potassium fertilizers inthe soil is strongly affected by clay minerals.Soils derived from volcanic ash contain largeamounts of amorphous minerals such asallophane. These retain much of the appliedP, so that it is not available to plants. Theapplication of phosphate fertilizer to such soilin bands or hills along with organic matterwill reduce phosphate retention.

Phosphate retention also occurs to alesser degree in soils with oxidic andkaolinitic mineralogy. Growers are recom-mended to apply phosphate in the form ofphosphate rocks that can provide calcium aswell as low cost P on acid soils. Becausethese soils generally have a low cationexchange capacity, potassium fertilizer is splitinto several applications to prevent losses byleaching. However, in soils where the claytends to swell when wet and shrink when dry,(smectitic), potassium fertilizer can be appliedall at once before planting, because thenutrients are retained until it is absorbed bythe plant.

Nutrients in coarse textured soils areprone to leaching losses. The application oforganic materials such as compost to thesesoils will increase their nutrient retentioncapacity.

Tillage of soils with smectitic minerals isparticularly sensitive to the water content ofthe soil. Such soils require higher levels ofenergy to till when they are dry or containexcess water. Nitrogen fertilizer is needed bymost crops, although legumes need less of it.The type of nitrogen fertilizer applied isusually based on soil acidity. Ammonium

sulfate and potassium sulfate are notrecommended for acid soils. Urea tends toincrease soil pH, and is applied more often toacid than to alkaline soils.

Sustainable upland farming

Whether upland farming is sustainabledepends not only on the condition of thephysical environment, but also on social andeconomic factors, infrastructure andgovernment policy. Policy becomes moresignificant with the integration of theIndonesian economy into the world economy.To be sustainable, a technology must not onlybe technically sound, but it must also beenvironmentally safe and economicallyfeasible. On other hand, however profitablean agricultural enterprise is, it cannot last longif it causes the physical environment tobecome degraded.

Upland agriculture on tropical soils thatare generally acidic with low fertility shouldfocus on perennial crops such as trees orpasture, rather than on traditional food crops(Amien 1990). Erosion can be reduced bymaintaining a permanent soil cover.Decomposed plant residues in roots, leaves,etc., will improve the soil's physical conditionand increase the percolation rate, reducerunoff and eventually diminish erosion.Organic materials also improve soil fertility,by directly adding to the soil's nutrient supplyor by increasing the nutrient absorption ofplants. Green manure from legume cropresidues is reported to detoxify aluminum inacid soils (Hue and Amien 1989).

The continuous cultivation of annualfood crops using a low level of inputs willcollapse within a relatively short period,mainly due to weed infestations (Sanchez etal. 1987). This can be seen in the increasinginfestation by Imperata grass (Imperatacylindrica) of land that was formerlycultivated but is now abandoned. Continuousmonoculture of the same crop does notproduce a sustainable yield because of thebuildup of pathogens (Valverde and Bandy1982).

Several methods have been suggested ofmaintaining the productivity of upland farmingon acid soils. Von Uexkull (1982, 1984)suggested a low-cost management system,using a leguminous cover crop and a variant

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of shifting cultivation within the crop coverarea. Another way of restoring andmaintaining soil fertility is alley cropping.Trees or shrubs are grown in hedgerows alongthe contours, with strips of annual cropsgrown between the hedgerows. The deep-rooted, leguminous trees used in thehedgerows recycle the leached nutrients thatcannot be reached by shallow-rooted foodcrops, as well as preventing erosion. Cuttingsfrom the leguminous trees provide greenmanure, as well as fodder for livestock.Nevertheless, the long period of time betweenplanting hedgerows and being able to prunethem for fodder and manure, and the highlabor demand, make this method lessattractive. Furthermore, it is not yet clearwhether the hedgerows can recycle leachednutrients effectively if they are frequentlypruned (Amien 1990).

Agroforestry is the term given to anytype of farming involving trees. Althoughagroforestry is widely practised by indigenouspeople, it is the least studied of all tropicalagricultural systems. Research intoagroforestry will require an interdisciplinaryapproach that must include agronomists,anthropologists, geographers, rural sociologistsand ecologists, as well as economists. It alsoimplies a perceptual change, to an emphasison sustainability rather than import substitution(Hecht 1986). Basic agroforestry techniquesneed a lot more study, such as the best plantcombinations and their spatial arrangement indifferent kinds of environments. Interactionbetween different plant species is usually sitespecific, making it difficult to generalize fromisolated studies. In terms of the technologyavailable today, agroforestry can be regardedas a promising field of research for the humidtropics, but not as a system which can bewidely recommended for agriculturaldevelopment (Alvim 1982).

Crop diversification by planting severalcrops in each field has many benefits. Evenduring the worst times, at least some plantswill give a yield. There are also more cropresidues to provide livestock feed, greenmanures and mulches. The residues oflegume crops such as Leucaena and Sesbaniacan provide protein-rich feed supplements.The role of livestock in integrated uplandfarming is very important, as a source of milkand meat as well as savings and capital.

Livestock also serve as draft animals forploughing and transporting agricultural inputsand produce. If legume crop residues areused livestock feed, rather than applied as amulch or green manure, the nitrogen andcarbon cycles become more efficient.

DECISION SUPPORT TOOLS

Expert systems

Computer technology is now playing amajor role in agrotechnology transfer and landevaluation. The role of computer technologyin database management, simulation,geographic information systems and expertsystems has gained wide acceptance during thelast decade (Jones et al. 1986). Expertsystems belong to the field of artificialintelligence. The name refers to the use ofcomputers to solve problems in ways thatwould be natural to humans (Waterman 1986).

An expert system can be seen as acomputing system which uses organizedknowledge about a specific field to solve aproblem. Expert systems can be developedfor diagnosis, classification, decision-making,tutoring, retrieving information etc. Althoughtraditional computer programming techniqueshave been used to solve these same kinds ofproblems, a major difference exist betweentraditional programs and expert systems. Intraditional programming, the problem-solvinglogic and knowledge are integrated together inthe program code, and are hidden from allbut the programmers. In expert systems, theknowledge remains separate and easilyaccessible to the user, the human expert, andthe programmers (Jones et al. 1986).

The most innovative part of expertsystems is the ease with which a wide rangeof information can be presented and used inmaking decisions. This information rangesfrom quantitative information, includingstatistical relationships such as regressionequations and physical and chemical laws, toless precise concepts and ideas that have beengained by experience in the field.

Expert systems can be connected toexternal databases. By having access to adatabase, the expert system can infer siteconditions from available data by considering,for example, the geographic location of the site.

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Expert systems for selecting cropsproduction systems in the tropics

An expert system for which analyzes thesuitability of different crops and productionsystems has been developed for Indonesia(Amien 1986). It tries to providerecommendations on appropriate land usebased on characteristics such as slope, soiltexture, acidity and drainage. If factors suchas steep gradients, very coarse soil texture,deep peat, or very low pH are present aslimitations, the system recommends differentagricultural systems which are appropriate forsuch conditions.

If the crop suitability assessment mode isselected, the system will request additionaldata on moisture and temperature regimes.Options will be given for a wide range ofcereals, root crops, grain legumes, fiber crops,oil crops, beverage crops, vegetables and fruitcrops, and cash crops such as sugarcane,tobacco, rubber, and pepper, based on soil andclimatic conditions of the land. If the land issuitable only for forestry, a range of timberspecies and other tree species is provided.Crop suitability is generally limited byinadequate or excessive water, or by extremetemperatures.

The system also suggests croppingpatterns on the basis of the water supply.Although water supply data is not alwaysaccurate, it can be inferred from drainage andthe number of consecutive wet months.Recommendations on methods of applying Pand K fertilizer are based on soil claymineralogy. Information on soil mineralogy isalso the basis for recommending other soilmanagement options, such as organic manuringand appropriate methods of soil tillage. Thesystem also provides cautions about problemsoils such as potential acid sulphate soil andsoil with an alkaline pH.

Often the user does not have enoughdata to feed the system. In this case, thesystem tries to use information gained fromthe user's experience in the field. It askssimple questions on specific soil and landcharacteristics. Approximate soil acidity isinferred from the natural vegetation. Themoisture regime is inferred from soil drainage,and from the number of consecutive drymonths in which the monthly rainfall is lessthan 60 mm. Because the system is designed

for tropical regions, the soil temperature isinferred from the height of the land above sealevel. Land at an elevation of less than 750 mis in the hottest temperature class, land at 750- 2000 m is the intermediate class, and landabove 2000 m is the coolest.

It is more complicated to determine soilclay mineralogy. This is based on severalsoil characteristics, including the parentmaterial, the soil texture, the color of thesubsoil, and whether or not the soil cracksopen during the dry season. The color ofsurface soil is usually darker than that of thesubsoil, because of its higher organic mattercontent. Therefore, input requested by thesystem includes the color of the subsoil. Ifoxidic minerals are present, the color ofsubsoils is reddish or yellowish. Informationon soil clay mineralogy is very valuable insoil management.

Ideally, an expert system should have alarge, comprehensive knowledge base toprovide detailed information on land use andsoil management. However, a large system ofthis kind requires sophisticated computers.Since the end users are likely to be extensionworkers who have limited access tocomputers, the system was designed to becompact.

AN EXAMPLE OF LAND ALLOCATIONANALYSIS FOR SUMATRA, JAVA,

KALIMANTAN AND SULAWESI

Sumatra

Sumatra is the second largest island ofIndonesia, with almost a quarter of thecountry's total area. Because of its vicinity toJava, and to the capital city, Jakarta, Sumatrais the most developed region in agricultureand industry outside Java. Almost all ofSumatra is cultivated, with plantations ofoilpalm, pepper, coffee, and rubber etc. Afavorable climate, especially a well-distributedhigh rainfall, has facilitated agriculturaldevelopment. Agriculture related industryflourishes, from fertilizer plants to paper mills,and from oil palm and rubber processing topineapple canning.

Mainly on the basis of relief, sinceSumatra has a rather uniform warm andhumid climate throughout the year, Sumatra isdivided into six regions (Scholz 1983). It is

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also divided into six zones, based on gradient,soil characteristics and climatic data (Table 2).As recommended by the expert system, zonesI, V, and VI must left in forest to protect theenvironment in general. Zone II can beutilized for permanent crops only, Zone III foragroforestry, and Zone IV for annual crops.

Land is designated for forestry if it hasvery steep slopes, or because of the poor hasquality of the soil. Other forested areas aremangrove forest along the coast growing inmarine soils. Suitable tree species for foreston deep peat soils include damar (Agathis sp),ramin (Gonystyllus bancanus) and kruing(Dipterocarpus sp.).

In the permanent crop zone, crops areselected according to the soil and moistureregime. Because Sumatra is almost uniformlyhumid, plant performance is limited mainly bythe height above sea level. On lands with anelevation of up to 750 m, the crop optionsare rubber, coconut, oil palm, and fruit trees.In areas higher than 750 m, the most suitablecrops are tea, citrus and cinnamon.

According to the forestry land usecensus, the total forested land in Sumatra is55.3 million ha (BPS, 2000). However, therecommended forested area based onagroecological zoning is only about 41% ofthe total forest area. This implies that morethan 25 million ha of the current forestedland can be converted into perennial treeplantations or used for agroforestry or annualcrops. However, optimal land use is hinderedby the land classification system, under which65% of the land lies within the Department ofForestry land boundaries (although about 30%of it is not under forest cover) (World Bank1991).

Java

The island of Java is one of the mostdensely populated areas in the world. Achain of volcanoes, some still active, haveenriched the soil so that it is generally veryfertile. Since ancient times, Java has been acenter of educational, economic, cultural andpolitical activity in Indonesia. Java has beenuntil recently the main producer of rice andsugar in the country. The fertile plain in thenorth of the island is intensively cultivatedthroughout the year. To the south, fertileagricultural lands have been developed in

several river basins.However, because the growing population

has already occupied all available land in theplains, people have invaded the hilly andmountainous regions. If these are farmedwithout conservation measures, the result iserosion and increased flooding. For thisreason, many reservoirs have been constructedto manage water resources for irrigation andsanitation, as well as hydroelectric power.About 60% of the population of Indonesialive in Java and Madura, and almost all ofthe land is being utilized for agriculture(75%). With a population growth of 1.7%annually, the number of families that dependupon agriculture will increase by about150,000 each year. This will result in theconversion of forest land at a rate of 18,000ha annually, with about 40,000 ha ofagricultural land being converted each yearinto residential and industrial purposes (WordBank 1990).

Java's well-developed infrastructure andthe availability of skilled human resourceshave made it the center for industrialexpansion that has taken place on much ofthe fertile agricultural land.

The increasing population of Java isaugmented by migration from the outer islandsof people attracted by educational andeconomic opportunities. Three of the biggesturban centers in Indonesia are located in Java.Transmigration and family planning programsare the principal policies to overcome theseproblems.

About two thirds of Java is hilly ormountainous, with only one third beingrelatively flat. Upland agriculture differs fromlowland rice farming in several ways. It ischaracterized by diverse crops, lowproductivity and low wages. Upland farmingoffers fewer off-farm employment opportunitiesthan lowland rice farming, and theinfrastructure such as roads and extensionservices is poor.

Agricultural production plays a greaterrole in regional development when it generatesnot only raw materials, but also value-addedprocessed goods from agro-industry. Withgood planning, such as cultivar standardizationwithin areas of sufficient economic size,investments into industries based on theprocessing of agricultural products willgenerate incomes and jobs.

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Java is divided into six zones, eachfurther divided into six subzones. In contrastto Sumatra, Java has no significant areas ofpeat soil, but has a thin strip of sand duneson the southern coast. This strip, like someof the marine soils along the northern coast,must be utilized as a buffer forest to protectthe coast from erosion. Java has morediverse temperature and moisture regimes,including some semi-arid areas.

Because of the high population density,much of the land on Java that should havebeen preserved for forestry and conservationpurposes has already been used for agriculture.Just over 6 million ha of Java are in forest.Because of population growth, these areas willundoubtedly continue to diminish. The landcurrently within the forestry deparatmentboundary in Java is about 22%, or about800,000 ha less than the recommended area.Furthermore, many of the designated forestrylands are not in fact forested.

Between 1980 and 1999, the populationof Java increased by 29.16 million. With theexception of tree crops, which increased by0.004 ha, the area of agricultural landdecreased. The area cultivated in annualupland crops and paddy rice fell by 0.03million ha and 0.04 million ha, respectively.Moreover, the character of rice-growing areashas been changing. As lowland rice fieldsbecome covered with houses and factories, tocompensate for these losses, 0.49 million haof steep lands with slopes of more than 15%have become used for agriculture. Althoughmost of this sloping land is terraced, thisimproper land utilization causes erosion, andland degradation, and disrupts the hydrologicfunction of the watershed, resulting in frequentfloods and droughts.

Intensive agriculture that has expandedinto steeply sloping areas often causesdisasters such as landslides and floods.Agricultural systems on steep land should bebased on perennial crops so that the soil isprotected by the crop's canopy and rootingsystem. (Erosion is caused mainly by thedirect impact of raindrops onto the soilsurface), moreover, the rooting system of treeshelps to prevent landslides. By selecting high-value crops and by the development of agro-industry, the well-being of the people can beimproved in a long-term and sustainable way.

The best way to protect sloping land

from erosion is to maintain a continuousvegetation cover, particularly during the rainyseason. Other than perennial trees, manyforage grasses also serve to prevent erosion,because of their rooting systems and denseplant cover at the soil surface. In manystudies, grass strips have proved to be moreeffective in preventing erosion than tree crops.Because of their relatively low canopy, grassesdo not compete with food crops for sunlightin multiple cropping systems. Many uplandplots in Java have been terraced. Theterraces are more stable if grass strips areplanted along the edges and banks.

Kalimantan

Kalimantan is a part of Borneo thatconsists of four large provinces. Together,they make up 28% of Indonesia's total landarea. Kalimantan can be divided into hillyand mountainous regions with gradients ofmore than 15% (about 30 million ha); flatwetland (about 8.7 million ha), of whichabout half have peat soils; undulating landswith gradients of 5 - 8 % (about 6.1 millionha), with the remainder made up of dry plainsand rolling hills. Crossed by the equator,Kalimantan has two periods of high rainfalleach year. The climate is warm and humid,with no distinct dry season.

Although Kalimantan has abundant waterresources, the poor soil and steep gradientslimit its utilization for agriculture. Kalimantanis one of the least populated islands inIndonesia, with only 20 persons per km2,compared to 945 persons in Java and 88persons in Sumatra. Because of the scarcityof labor, the main agricultural products fromKalimantan are those which have the lowestlabor demand, such as timber, rubber, pepperand oil palm. However, Kalimantan is rich inenergy and mineral resources, including oil,gas and coal.

Forest cover needs to be preserved onmore than 51% of the Kalimantan's toupstream watersheds, and about 14% ofdownstream areas. At present, 3.7 million haare used for crops, including 1.1 million hafor lowland crops, and 1.7 million ha forupland agriculture (BPS 2000), the rest beingused for agroforestry and plantations. According to agroecological conditions,this agricultural area could be extended.

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Kalimantan could support 7.7 million ha ofplantations, 4.4 million ha of lowlandagriculture and 4.7 million ha of uplandcrops. Optimizing land use needs to becarefully planned, to avoid failure. In viewof the poor infrastructure and unfavorable soilconditions, as well as the labor scarcity, theemphasis should be on less labor-intensiveagriculture such as tree plantations.

Sulawesi

Covering more than 18 million ha,Sulawesi is a rugged island with many activeand extinct volcanoes. About 60% ofSulawesi is mountainous, and 14% is hilly.Volcanic activity has enriched the soil, andthe fertile volcanic soils of northern Sulawesiare Indonesia's main producers of coconutsand cloves, while those of South Sulawesi areimportant for rice. Rainfall patterns vary,with some areas having a single rainy seasonand others having two.

Sulawesi is relatively lightly populated,with only 75 persons per km2. Thepopulation is denser in the fertile volcanicsoils of the north and south. Well over halfthe population earns a living from agriculture.With a high proportion of steeply slopingland, about 83% of Sulawesi (14.9 million ha)should be left forested for conservationpurposes. The area suitable for agriculture isrelatively small, only 3.5% for tree plantationsand agro-forestry, 9.2% for irrigatedagriculture and 3.9% for upland agriculture.

At present, a larger area than this isbeing utilized for agriculture: 22.09 million haof tree plantation, 1.74 million ha of uplandannual crops and 0.89 million ha for of paddyfields. This indicates that more than 1.5million ha which are supposed to be kept asconservation areas are being used foragriculture. Furthermore, from 1979 to 1999tree plantations increased by 1.25 million ha,compared to only 0.25 million ha for paddyrice and 31 thousand ha for upland annualcrops. The area recommended for treeplantation and agroforestry is only 0.64million ha, but tree plantations, mainly ofcoconut and oilpalm, have been planted inmany areas suitable for annual crops.Understandably, because of the limited laboravailable, farmers have opted for farmingsystems with a low labor requirement, such astree plantations.

DATABASES AND GIS

Considering the limited quality andquantity of existing data, this firstapproximation of the agroecological zones ofSumatra, Java, Kalimantan and Sulawesi willbe refined and improved as more databecomes available. Improvements will befacilitated by storing basic data and analyticalresults on the database, along with digitizedmaps in the geographic information system.At a scale of 1:1,000,000, the map ofagroecological zones is appropriate as a basisfor national development planning, so that thedatabase described here has been developedon the more pragmatic basis of a "minimumdatabase".

The database contains information aboutterrain, soil and climate on a mapping unitpolygon basis that consists of slope, soiltexture, acidity, drainage, elevation, tem-perature regime, moisture regime and soilsuborder based on Soil Taxonomy. Thedatabase also contains administrative locationsand a range of agricultural commodities thatare suitable for each area. These commoditiescover various cereals, root crops, grainlegumes, oil, fiber and beverage crops,vegetables and fruit crops, as well as cashcrops such as sugarcane, tobacco, rubber andpepper.

AREA DELINEATION FOR LANDMANAGEMENT RESEARCH

Human beings have intervened to shapethe earth's surface in both positive andnegative ways. Driven by the basic need forfood, people have for thousands of years triedto produce their own food and clothing fromthe land they occupied. This is stillhappening in many places in the outer islandsof Indonesia, where traditional shiftingcultivation is being practiced. The presentstatus of the land in many parts of the outerislands, where more and more land is beingclassified as a forest conservation area, doesnot give the farmers any choice but to utilizethe land by shifting cultivation. In moredeveloped parts of the country such as Java,the land status inherited from colonial times,when upland agriculture was practiced onhigh, steep slopes, does not favor a morerational utilization of lands.

Fig. 1. Agroecological map of Southern Sumatra for national planning(Original scale 1:1,000,000)

Because different regions are at differentstages of development, the present land use isnot always rational or appropriate in terms ofenvironmental sustainability and economicfeasibility. If the recommended land usebased on agroecological conditions iscompared to the actual land use, large areascan be seen to be over-utilized or under-utilized. By comparing the ecologicallyoptimum land use and actual, present landuse, the types of interventions, along withresearch programs to support the intervention,can be properly formulated.

In areas where land is already properlyutilized, the aim will be intensification in theform of improved cultural techniques, newhigh-yielding cultivars, better fertilization andpest and disease management, and improve-ments in postharvest technology andmarketing. In areas where land is over-utilized, as when land appropriate forpermanent crops is planted with annual crops,the intervention is land rehabilitation throughdiversification. This will include introducing

conservation farming by planting more tropicalfruits instead of the traditional annual foodcrops. In Java, Bali and Lombok, wheremore off-farm employment opportunities areavailable, there is often a shortage of farmlabor. This shortage can be overcome bypromoting commodities that require less laborsuch as tree plantations.

If land is being underutilized,intervention should take the form ofagricultural expansion. There are many partsin the outer islands where land suitable foragriculture is classified as forest. Such landrequires a change in status, and newinfrastructure such as roads, bridges and ports.

For each type of intervention, differenteconomic, social and cultural considerationshave to be taken into account. By collectingthis kind of information, the cost of producingparticular commodities and the price of theproduce can be assessed. An economicevaluation of the most profitable choice of allthe suitable crops can then be made, usinglinear programming software.

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20

It is necessary to run different marketingscenarios, whether at a local, regional, nationalor global level. Intensification and expansionare required if the market demand is high,and diversification into more profitable cropsif there is an excess supply.

CAPACITY BUILDING AND DISSEMINATION

Given Indonesia's vast and diverseresources, a centralized approach to resourceinventory and analysis is not feasible. Bothagricultural research program and training havebeen given a regional emphasis since 1996.Between 1996 and 1999, more than 100people have been trained in characterizing andanalyzing agricultural resources, using theagroecological approach. With guidance andsupervision, these trained personnel utilizedexisting information to delineate regional (Fig.1 and Fig. 2) resources, at a scale larger than1:250,000. Such a scale provides moreinformation, such as the delineation of peatand coastal areas into conservation andagricultural uses.

Shallow and more decomposed peats aresuitable for annual crops, while other peatareas should be used for perennial crops.The area at the center of the peat domeshould be left untouched, for conservationpurposes. Coastal areas should maintain abuffer zone for coastal protection, by keepingthe mangrove forests while allowing someaquaculture based on brackish water fishes.

As such information becomes available,sites for research assessment can be properlyselected. For dissemination purposes, a seriesof workshops were held in 1999 and 2000.They were attended by representatives fromregional development boards, agriculturalservices and local universities. The workshopProceedings were published and distributed toall the stake-holders in the regions.

REFERENCES

Alvim, P de T. 1982. A perspectiveappraisal of perennial crops in theAmazon Basin. In: Amazonia: Agricultureand Land Use Research, S.B. Hetch (Ed.).CIAT, Cali, Colombia, pp. 311-328.

Amien, L.I. 1986. Expert system for cropssuitability and agriculture systems in thetropics. Indonesia Ag. Research and

Development Jour. 8 (3 and 4): 72-75.Amien, L.I. 1990. Utilization of Acid

Tropical Soils for Sustainable Agriculture.Indonesia Ag. Research and DevelopmentJour. 12, 2: 17-22.

Amien, I. 1997. Land resources analysis foragriculture development. Indonesia Ag.Research and Development Jour. 19 (1and 2): 1-12.

Amien, I. 1998. An agroecologycal approachto sustainable development. In: MultipleObjectives Decision Making for Land,Water and Environmental Management,S.A. El-Swaify and D.S. Yakowitz (Eds.).Lewis Publisher, Boca Raton, Florida,USA, pp. 465-480.

BPS. 2000. Statistik Indonesia. Biro PusatStatistik, Jakarta.

Eswaran, H. 1984. Uses of soil taxonomyin identifying soil related potentials andconstraints for agriculture. In: Ecologyand Management of Problem Soils inAsia. Food and Fertilizer TechnologyCenter, Taipei, Taiwan.

Hue, N.V. and I. Amien. 1989. Aluminumdetoxification with green manure. Comm.in Soil Sci. and Plant Anal. 20 (15 and16): 1499-1511.

Jones, J.W., H. Beck, R.M. Peart and P.Jones. 1986. Application of expertsystem concepts to agrotechnologytransfer. Proc. International Soil Sci.Congress, Hamburg, Germany.

Sanchez, P.A., J. Benites, and D.E. Bandy.1987. Low-input system and managedfallows for acid soils in the humidtropics. In: Soil Management underHumid Conditions in Asia and the Pacific,M. Latham (Ed.). IBSRAM Proc. No.5., Bangkok, Thailand pp 353-360.

Scholz, U. 1983. The Regions of Sumatraand their Agricultural Production Pattern.SARIF, West Sumatra, Indonesia.

Valverde, C.S. and D.E. Bandy. 1982.Production of annual crops in theAmazon. In: Amazonia: Agriculture andLand Use Research, S.B. Hecht (Ed.).CIAT, Cali, Colombia, pp. 243-280.

Von Uexkull, H.R. 1982. Problem soils forfood crops in the humid tropics. Proc.Int. Symp. Distribution, Characteristicsand Utilization of Problem Soils. Trop.Agricultural Research Centre, Ministry ofAgriculture, Forestry and Fisheries, Japan.

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Tropical Agriculture Research Series No.15, pp. 139-153.

Von Uexkull, H.R. 1984. Managing acrisolsin the humid tropics. In: Ecology andManagement of Problem Soils in Asia.Food and Fertilizer Technology Center,Taiwan, pp. 382-386.

Waterman, D.A. 1986. A Guide to ExpertSystems. Addison Wesley PublishingCompany, Reading, MA, USA.

World Bank. 1990. Indonesia: SustainableDevelopment of Forests, Land and Water.The World Bank, Washington, D.C.

Yost, R.S., S. Itoga, Z.C. Li and P. Kilham.1986. Soil acidity management withexpert system. Proceedings, IBSRAMSeminar on Soil Acidity, Land Clearingand Vertisols. October 13-20, 1986 KhonKaen, Thailand