The Effect of Soil Parent Materials on Yield of Cocoa

The research objectives were to analyze soil variability induced by parent materials for cocoa cultivation in Peninsular Malaysia. The research results can provide basic information on potential reserves of nutrients to improve soil productivity for cocoa cultivation. Soil samples were collected from two locations (Rengam series soil of Granite and Kuantan series soil of Basalt parent material respectively). The collected soil samples were completely analyzed in laboratory. The results showed that based on mineral resistance to weathering (sand and silt mineral sizes), mineral weathering of granite and basalt is divided into three categories, very slow weathered mineral (quartz and muscovite), slowly weathered mineral (K- feldspar, Na and Ca-feldspar and biotite), and easily weathered mineral (hornblende, augite, olivine, dolomite, calcite and gypsum). Losing mineral during weathering process from granite to clay is determined by the present of mineral in rocks. Such minerals (CaO, Na2O, K2O, MgO and SiO2) loosed 100 %, 95.0 %, 83.5 %, 74.7 % and 52.5 % respectively, but Fe2O3 is disappeared only 14.4 %. Soil properties characters of granite soil is more acid, has very low to low chemical soil fertility and is dominated by sand fraction, furthermore basalt soil is acid, has low to moderate chemical soil fertility and is dominated by clay fraction. Granite and basalt soils are able to produce bean yield 2300-2700 kg/ha in a year and 2000-2400 kg/ha in a year respectively. The production difference of both soils is around 300 kg/ha in a year. Keywords: Soil variability, analyses, parent materials, cocoa, Peninsular Malaysi