Nutrient Release Pattern from Compost Supplemented with Jatropha Cake on Alfisol of Ilorin, Nigeria

The mineralization of nutrients from compost supplemented with Jatropha cake was examined on an Alfisol of Ilorin, Nigeria with a view to determining its potential for fertility improvement.

Two kilogram soil (0-15 cm depth) was weighed into plastic pots, replicated three times and arranged in a completely randomized design. Compost Aleshinloye Grade B (un-amended compost) augmented with jatropha cake in different proportions was applied at the rate of 10 t /ha to each pot. The soil in the pot was incubated with the following treatments: AJ (30% Aleshinloye Grade B + 70% Jatropha cake), BJ (40% Aleshinloye Grade B + 60% Jatropha cake), CJ (50% Aleshinloye Grade B + 50% Jatropha cake), DJ (60% Aleshinloye Grade B + 40% Jatropha cake) including control (CO). At the end of 0, 3, 6, 9, and 12 weeks, the incubated soil were sampled and analyzed for pH, N, P, K, OC, Ca, NH4-N and NO3-N contents. Data collected were subjected to ANOVA and cluster analysis.

The results of Incubation of fertilizers applied increased soil pH. At 12 weeks, higher value (0.57cmol/kg) was obtained from mineralized exchangeable K by DJ treated soil. CJ significantly increased (P=.05) OC, NO3-N, NH4-N, total N and P.

Thus the result of this finding suggests that 10 t /ha CJ (50% Aleshinloye Grade B + 50% Jatropha cake) significantly increased the N and P.