Effect of irrigation interval and soil amendments on soil organic C, nitrogen and potassium of sandy soil and growth of Jatropha curcas L

Abstract

Inherently, sandy soil is low in all aspects of soil fertility and has a low capacity to retain water and applied nutrients. To improve the fertility of sandy soil as media growth for Jatropha curcas, clay and organic matter may have important role when they are incorporated to the sandy soil. This study investigated the effect of irrigation interval and incorporation of clay together with organic matter to sandy soil on soil organic C, N, and K and growth of J. curcas. The rates of clay and organic matter incorporated to top sandy soil were 5% clay + 0.8% organic matter and 10% clay + 1.6% organic matter. Two irrigation intervals tested were 10 day and 20 day. The results found that incorporation of 10% clay + 1.6% organic matter to sandy soil increased soil organic C, total N and exchangeable K which in turn increased the number of leaves and number of lateral branches of J curcas, while irrigation intervals had no effect on all parameters observed.