ASSESSMENT OF ABORIGINAL SMALLHOLDER SOILS FOR RUBBER GROWTH IN PENINSULAR MALAYSIA

Abstract

This study assesses an array of physiochemical soil properties from a sample of rubber smallholdings managed by a group of Orang Asli(original people) in northwest Pahang, Peninsular Malaysia. Malaysian smallholders in general face significantly lower productivity levels than the large rubber estates and plantations (Malaysian Rubber Board, 2002). Among smallholders, Orang Asli households generate the lowest rubber yields, earn the lowest non-rubber income, and are most threatened by land scarcity (RISDA, 2003). Furthermore, little is known about the soils of these smallholdings since most rubber-related soil surveys focus on estates and experiment stations (Pushparajah & Amin, 1977). An understanding of the morphological and physiochemical soil properties of Orang Asli rubber fields is a crucial step toward the efficient allocation of government resources that aim to enhance productivity, promote sustainable agriculture, and improve household welfare. The objectives of this project were to (1) determine the predominant physiochemical characteristics of these soils, (2) evaluate them with an established rubber suitability classification system, (3) group soils according to region, geomorphic position, and estimated soil series in order to make generalizations about soil limitations for certain soil types, and (4) offer methods by which to mitigate the effects of these limitations. We find that there is a great deal of heterogeneity within our sample with regard to both soil type and limitation. The most common physical limitations were related to flooding, uprooting, soil texture, and slope. Almost all soils were severely depleted in organic nutrients and base cations. Overall, these limitations were correctable via drainage, terracing, or establishment of a cover crop. It is recommended that any application of chemical fertilizer take soil type into account. (Soil Science 2005;170:1034-1049)