Fertilizer and lime response in acid soils of Sumatra

Abstract

Upland rice is one of the crops grown in newly opened acid soils in Indonesia. Farmers often abandon their acid soil farms after 2–3 years of cultivation because of marked yield decline. An experiment to determine whether fertiliser and lime, alley cropping and crop rotation could minimise productivity decline was established in a kaolinitic isohyperthermic (Tropeptic Haplorthox) soil, with initial pH of 4.3, low organic carbon, Bray II extractable P and CEC, but high exchangeable Al. Half of the field was alley cropped with Flamengia congesta and the other half was with narrow grass strips along the contour. Yield of rice during the first year ranged from 0.75 to 1.71t ha^-1, the lowest was from the plots receiving no fertiliser and lime while the highest was from those receiving fertiliser and lime. The same trend was observed for soybean and maize grown after rice. The yields of all 3 crops declined during the second year. Greatest decline was observed from the maize crop followed by soybean and rice. However, when a better cultivar of rice was grown in the third year the yields were comparable to the first crop of rice.