Indonesian Soil Research Institute, Jalan Ir. H. Juanda 98, Bogor 16123, Indonesia
Submitted: 14 March 2011; Accepted 24 October 2011
Agriculture in Indonesia intensifies from the swidden to very intensive systems and expands rapidly, including to steep slopes and peatland areas. These have implications to the environment and the system’s sustainability. Cereal and pulses-based farming systems uses moderate amount of chemicals and thus poses little threats to water quality. However, these systems encroach into steepland accelerating erosion and depleting soil fertility. Intensive vegetable farming applies around 50 Mg/ha of barnyard manure, 300 kg/ha of N, and high rates of pesticides, posing a threat to water quality in the downstream areas. Plantation develops very rapidly, including to forest and peatland areas. Conversion, to plantation crops, of forest (with 132−300 Mg C/ha) decreases, but of shrub (with 15−40 Mg C/ha) and Imperata grassland (with < 5 Mg C/ha) increases the carbon stock to 30−50 Mg/ha. The traditional tree-crop-based agriculture, characterized by a mixture of several species, reduces erosion and maintains relatively high carbon stock and biodiversity. Lowland rice (paddy) system, currently covering around 7.9 million ha area, has been practiced sustainably for thousands of years. Despite providing food security and various environmental services, this system is under tremendous pressures of conversion to industrial and settlement areas. Meanwhile, some 20 million ha peatland of Indonesia is being converted at a rate of 1.3% annually for agriculture and silviculture. The carbon-rich land rapidly emits carbon once it is cleared and drained. Indonesian agricultural development is challenged by the demand to keep a high level of production with minimal negative impacts to the environment. This can be achieved by prioritization of low carbon stock land for agricultural expansion, rationalization of fertilizer application, minimization of intensive agricultural expansion to steepland, and safeguarding paddy field from conversion.
Keywords: Agriculture, steepland, peatland, erosion, plantation, carbon stock
Paper published in Jurnal Litbang Pertanian 30(4), 2011