Soils and Agriculture in Borneo.

Abstract

Borneo is the third biggest island in the world. It is under the tropical rainforest climate and most of the land is covered with lowland dipterocarpforests, where soil properties are mainly determined by the parent materials (Tertiarys and stone and shale) and topography. The red yellow podzolic soils by the Malaysian soil taxononly, Acrisols by the FAO-UNESCO classification, or U1tisols by the US soil taxononly are widely distributed on the hillyland, while peat soils and alluvial soils are distributed in the lowland. Some arenacious soils are found in between hills and lowlands, where white coarses iIiciouss and ぉare accunlulated (kerangas) and hold the kerangas or heath forests. Soil nutrients in the for ωt soils were not always partialized on the surface soils as was often pointed out for the tropical forest soils. The rate of nutrient partition to the surface soils (5em/70cm) is almost equivalent to those found in the temperate forest soils of Japan. Landusecapability is mostly determined by the slopes and subdivided by the soil acidity. The shift in gcultivation is one of the nlajoragriculturalpracticesinBorneoisland.Comparedwith theoilpalmplantationandpepperfield , ricecultivationontheslopinglandwithoutanyplowingcauses lesssoilerosion.Thus, sustainabilityofshiftingcultivationismorethanthatofoilpalmandpepper cultivation.However, consideringthecashcropcultivationofthelocalpeople, awellorganized agroforestrysystemshouldbeintroducedtoprotectagainsttheseveresoildegradationonthesloping lands.