Sustaining agricultural land in Malaysia : policies, prospects and problems

In Malaysia, sustainable agriculture is only possible if the strategies of land use involve optimum utilisation of the resource base to ensure continued stable biological production whilst maintaining environmental stability under a regime of constant inputs. The basic principle of sustainable agriculture is the continuing conversion of solar energy into various products, food or otherwise useful to man. Depending on cloud cover and altitude, about 130-220 KCal solar energy per cm* is received in the tropics where the potential dry matter production of the natural vegetation is about 146 ton in the humid tropics. The basic question is why is it that in spite of the potential of producing two to three times more than in temperate regions, many areas in the wet humid tropics fail to do so? What are the fundamental and major characteristics of the environment that we need to consider in the development of farming systems that are sustainable in Malaysia? The answers may be sought in the appreciation of how natural systems operate. From these ecological lessons appropriate agricultural policies can and should be developed. The tropical rainforest is the source of copious vegetation. A large proportion of these forests are supported by soils referred to as Oxisols or Ultisols which are acid, kaolinitic, with poor cation-exchange capacities and yet, despite the apparent poor condition of these soils a very considerable biomass is supported. The rainforests have been maintaining itself for millions of years because the build-up of nutrients in the vegetation undergoes a closed life cycle with only minimal loss of nutrients due to soil erosion. The fundamental factor influencing 'sustainability' in the rainforest soil-ecosystem is the amount of organic matter returned to the surface of the soil through litter accumulation. Only systems that can emulate these characteristics of the tropical rainforest, such as the Hevea-soil ecosystem, can be sustainable under the conditions of high rainfall on landforms dominated by valley slopes which cover about 80 percent of the landmass of Malaysia. This paper discusses the current agricultural policies