| Resource management for upland areas in Southeast Asia - An information kit |
|2. Integrated upland systems management|
Traditional agroforestry systems are found throughout Indonesia, including the kebun-talun and pekarangan systems in Java, and the multistoried agroforestry gardens in Sumatra. Introduced agroforestry systems also are common in many parts and are integrated into forest development programs on forest lands, as well as being widely practiced on private farm lands.
Farm-based agroforestry systems
The pekarangan (homegarden) is a mixture of annual crops, perennial crops and animals (including livestock) in the area surrounding a house. It is an integrated system with definite boundaries that serves a variety of economic, biophysical and sociocultural functions. The homegarden system originated in Central Java and spread to East and West Java in the middle of the eighteenth century.
Kebun-talun and homegardens in West Java generate relatively good income and are good sources of calcium, vitamin A and vitamin C.
A typical homegarden has a similar structure from year to year, though there may be some seasonal variations. The lowest two layers (up to 2 m in height) are dominated by starchy food plants, vegetables and spices. Cassava and ganyong (Canna edulis) are the most common plants found in the homegarden. The next layer (two to five meters) is dominated by bananas, papayas and other fruit trees. The five to ten meters layer is also dominated by fruit trees or other cash crops, such as cloves. The top layer, higher than 10 meters, is dominated by coconut and other trees, e.g., Albizia, for building materials and firewood.
The kebun-talun system usually consists of three stages: kebun (garden), kebun campuran (mixed garden) and talun (mixed tree garden). The first stage, kebun, involves clearing the forest and cultivating annual crops. These crops are generally consumed by the farm household, with part of the produce sold as cash crops.
In the kebun stage, three vertical layers of annual crops predominate: the lowest layer consists of creeping plants that occupy the ground below a height of 30 cm. The layer from 50 cm to 1 m is occupied by vegetables, and the upper layer includes maize, tobacco, cassava or leguminous vines supported by bamboo sticks.
Top layer (>10 m)
Coconut, Albizia, other trees
5-10 m layer
Fruit trees: Soursop, jackfruit, duku (Lansium domesticum), guava, mountain apple, cloves
2-5 m layer
Bananas, papaya, other fruit trees
1-2 m layer
Ganyong (Canna edulis), Xanthosoma, beans, spinach, cassava, gembili (Dioscorea esculenta)
Lowest layer (< 1 m)
Taro, Xanthosoma, chili pepper, eggplant
After two years, tree seedlings start to grow, leaving increasingly less space for the annual crops. The kehun gradually evolves into the kebun campuran, in which the annuals are mixed among half-grown perennials. The economic value of the mixed garden is less than that of the garden, but the biophysical value becomes higher. The diversified nature of the kebun campuran also enhances soil and water conservation. Erosion in the talun system is minimal, because undergrowth and litter are abundant. When the undergrowth and litter are removed, erosion may increase substantially.
In the kebun campuran, shade-tolerant plants such as taro occupy the space below one meter. Cassava forms the second layer from one to two meters height and the third layer is occupied by bananas and trees.
After harvesting the annual crops in the kebun campuran, the field may be abandoned for two to three years to become dominated by perennials. This stage is known as talun and is the climax stage of the kebun-talun system.
The talun is dominated by a mixture of perennial trees and bamboos, forming three vertical layers. The talun stage can take a variety of forms such as woodlots (for firewood and building materials), bamboos and mixed perennials.
The three-strata system
The three-strata system is a method of planting and harvesting grasses, legumes, shrubs and trees in such a way that animal fodder will be available throughout the year. The practice was developed by households in the island of Bali. The first layer, consisting of grasses and legumes is intended to supply fodder at the beginning of the wet season. The second layer, consisting of shrubs, is to supply fodder in the middle and the end of the wet season. The third layer, comprised of trees, is to supply fodder during the dry season.
The three-strata system divides a piece of land into three parts:
The nucleus is maintained for food production. The blanket is divided into a number of compartments, with each compartment cultivated with various grasses and legumes.
Fodder tree species are planted around the boundary at a spacing of 2 trees every 5 m. Between these trees Gliricidia or Leucaena shrubs are planted at a 10 cm distance between the shrubs.
Animal stocking rates can vary from low (0. 5 ha per cow) to high (0.25 ha per cow) due to improved fodder availability. Cattle raised in the system grow rapidly and are ready for market at an early age.
Alley cropping in the semi-arid provinces of East Indonesia
This technology has been developed in dryland farming programs in the semi-arid provinces of Nusa Tenggara since the early 1980s. The technology consists of hedgerow planting on contour lines with legume species. Before 1986, the hedgerow mainly consisted of lamtoro gung (Leucaena leucocephala); but after the psyllid (Heteropsylla cubana) infestation, Gliricidia septum and Calliandra calothyrsus were used. The hedgerows are intended for enhancing soil and water conservation. Between the hedgerows, annuals, perennial crops and grasses are planted.
In Sumbawa and other islands, live fences and rock walls are constructed to protect the crops against grazing livestock and wild animals.
Forest-based agroforestry systems
Shifting cultivation (also called swidden or bush fallow agriculture) is widely practiced in most Indonesian islands, except Java. Shifting cultivation includes a variety of practices occurring in a diversity of environments under many specific circumstances.
In Apo Kayan (East Kalimantan), almost all the forests cleared for agriculture are secondary forests and the fallow period is between 10 to 30 years. The farmers believe that the fallow period should be long enough to reduce weeds and to prevent the short-term degradation of the forest into scrub. Occasionally, sites may be left unused for even longer periods (40 to 50 years) to prevent gradual declines in fertility and an increase in weedy species. The farmers recognize the merits of long-term swidden management.
In Long Segar (also in East Kalimantan) shifting cultivators clear more primary forest than secondary forest for swiddens. People in Long Segar grow rice, easily selling the surplus through trade boats or to local markets. For this reason and because of the availability of chainsaws and fuel for motor boats, the area cleared and cultivated by Long Segar farmers is about 0.4 ha per capita per year, or about 33% larger than in Apo Kayan. The total area cultivated in 1979-1980 was about 400 ha, of which 82% was primary forest. Because of market, technology and population pressure, the rotation is becoming shorter. The recovery of such fields to forest is slow and, consequently, there is danger of land degradation.
Improved fallow technology is one of the alternatives to control destructive shifting cultivation practices and to develop more sustainable dryland agricultural systems. Abandoned fields are planted to the fast-growing cover crop, Pueraria javanica, to rehabilitate soil fertility and as a perennial cash crop. Food crops can again be planted after 3-4 years—a much shorter fallow period than traditionally followed
This revised cropping pattern will produce rice and cassava within a short period; pineapple, ginger and peanut in the near term and melinjo (Gnetum gnemon) in the long-run.
Multistoried agroforestry garden system in West Sumatra
The system is characterized by an intensive integration of forest species and commercial crops, forming a multilayer, forest-like system. The intimate association of different species provides both subsistence and commercial products which supplement rice production.
Various tumpangsari methods exist. They are introduced agroforestry systems designed to meet the subsistence needs of households with limited access to cultivable lands.
The implementation of tumpangsari in Java's teak forests includes four main activities: (1) site preparation, (2) seed preparation; (3) planting and (4) maintenance. The spacing of the main crop (teak) is generally I x 3 m; Leucaena is planted as a dense row in the middle between the teak rows. Additional crops can be planted in the I . 5 m-wide space between the teak and the Leucaena rows.
Similar activities can also be carried out in the establishment of plantations of other timber species, such as Pinus, Agathis, Altingia and Swietenia. Tumpangsari can also be found in rubber (Hevea) plantations, especially among smallholders. Due to the psyllid infestation problem with Leucaena, other species for interplanting need to be tested: Acacia villosa, Calliandra calothyrsus and Gliricidia.
Inmas or intensified tumpangsari
Intensified tumpangsari includes the following technologies:
· high-yielding crop varieties
· improved soil conservation and tillage methods
· insecticides (if necessary)
· correct timing for planting and fertilizing with respect to rainfall.
Since the 1970s, the intensified tumpangsari approach in teak forests has given satisfactory results and is increasingly being applied over larger areas. With the use of selected superior crop varieties and crop fertilization (in the range of 90-100 kg urea and 60-150 kg triple super phosphate per ha), together with the use of insecticides, yields of dryland rice may increase from 700 kg to 2,000-3,000 kg per ha.
Another example of intensified tumpangsari is vegetable tumpangsari in the Lembang area. Farmers in Lembang cultivate high-value vegetables between pine and other tree species on forest as well as on private lands. The vegetables include tomato (Lycopersicum Iycopersicon), potato (Solanum tuberosum), cabbage (Brassica oleracea), Chinese cabbage (Brassica pekinensis), white beans (Visum sp.), chili pepper (Capsicum anuum), kidney bean (Phaseolus vulgaris). Dryland rice (Oryza sativa) is also grown.
West Sumatra multistorey system
Cultivated annual crops
Chili (Capsicum anuum), eggplant (Solanum melongena), maize (Zea mays), beans ( Vigna spp., Phaseolus spp.), cucumber (Cucumis sativus)
Durio zibethinus, Pterospermum javanicum, Toona sinensis, Cinnamomum burmani, Myristica fragrans, Coffea canephora
Damar mata kucing agroforestry in Krui
Damar mate kucing is a resin of Shorea javanica produced in artificial forests in Krui, Lampung, in Sumatra. The resin is a cash crop sold throughout the year. The damar trees dominate the ecosystem. Other products are fruits, vegetables and other horticultural products, including langsat (Aglaia domestika), duku (Aglaia dookoo), jackfruit (Artocarpus heterophyllus), menteng (Baccaurea racemosa), durian (Durio zibethinus), aren (Arenga pinata), coffee (Coffea spp.), doves (Syzygium aromaticum), bamboo and rattan.
Whole rotation, or integrated tumpangsari
A more recent variation of tumpangsari is the integration of the approach into social forestry programs which include formation of farmer's groups, longer-terra tenurial arrangements and more flexibility of farm households to plant food crops.
In traditional tumpangsari, farmers are entitled to plant food crops between the young forest trees for only about two years. In the integrated tumpangsari, they are also allowed to grow fruit trees, grasses and other kinds of plants between the timber trees during the whole rotation period of the forest crop. The various planting materials for the forest, as well as the non-forest trees, are provided by the Forestry Service. The farmers may harvest the fruits, fuelwood, grasses, medicinal and other plants during the rotation period of the forest crops.