Department of Crop Production, Kwara State University, Malete, Nigeria
Purpose This study was conducted to determine the efect of compost supplemented with jatropha cake on maize (Zea mays L) yield in a degraded soil and their residual efects on soil fertility in Ilorin, Nigeria. Methods Field trials were conducted at Kwara State University Teaching and Research Farm, Malete, in 2016/2017 cropping season. The treatments consisted of control, un-amended compost Grade B supplemented with Jatropha cake AJ (30% Grade B + 70% JC) at 1.5 t/ha, BJ (30% Grade B + 70% JC) at 2.0 t/ha, CJ (50% Grade B + 50% JC) at 2.5 t/ha including NPK at 60 kg N/ha. The treatments were arranged in a randomized complete block design (RCBD) and replicated three times. Results Maize grain yield (3.1 t/ha) was obtained from CJ at 2.5 t/ha this was signifcantly (p < 0.05) greater than that of NPK treatment (2.2 t/ha) after the frst cropping. At second trials, maize grain yield values gotten from CJ at 2.5 t/ha were also signifcantly (p < 0.05) greater than that of NPK values. Treatments CJ at 2.5 t/ha signifcantly (p < 0.05) improved soil pH, available P and exchangeable K. Conclusion Fertilizer 50% Grade B + 50% Jatropha cake at 2.5 t/ha had a signifcant and positive efect on soil fertility after harvesting of maize when compared with NPK in both cropping.