Residual Effect of NPK 15-15-15 Fertilizer and Cassava peel Compost on Soil Properties and Maize Grain Yield
Residual effect of organic fertilizers promotes the carry-over benefits of the earlier applied fertilizers on soil and the succeeding crops. This frial examined residual effect of single as well as different combinations ofNPK 15-15-15 and cassava peel composts (CPC) on soil physico-chemical properties, harvest index, biomass and grain yield of maize. Six treatments fitted into randomized complete block design (RCBD) and replicated three times were investigated. Six treatments composed of control, mineral fertilizer, cassava peel compost and their combinations. Analysis ofvariance (ANOVA) was used for all the data generated and the differences between treatment means were separated using Duncan multiple range test (DMRT) at ps 0.05. Regression and correlation analyzes were used to assessed the relationship between residual NPK fertilizer and cassava peel compost and the measured parameters. Plots that previously received combined application of 50 kg NPK ha-I and 3.75 t CPC ha-I improved soil physico-chemical properties better while plots with previous history of combined application of 100 kg NPK ha-I and 2.5 t CPC ha-I gave highest maize grain and biomass yield. The amendments had positive and significant correlation with clay percentage (r2 = 0.58) while total organic matter (r2 = 0.41 ) and total nitrogen content (r2 = 0.22) were positively correlated with the applied soil amendments but not significant. Both grain and biological yields exhibited positive and significant relationship with amendments (R2 = 0.97).