MODELLING EFFECTS OF RESIDUAL ORGANIC MATERIALS ON PRODUCTIVITY OF MAIZE (ZEA MAYS L.) FOR SUSTAINABLE SOIL FERTILITY RESTORATION IN THE GUINEA SAVANNAH ZONE

Abstract

A field experiment was conducted at Nyankpala, near Tamale during the 2014 cropping season and continued during 2015, to investigate one year residual effects of indigenous organic materials (biochar, groundnut shell, rice husk and rice straw) on yield components and yield of maize. It was a 4×3×3 factorial experiment consisting of 4 organic materials at 3 levels (2.5, 5 and 7.5 t ha-1 on dry matter basis) and 3 N levels (0, 45 and 90 kg/ha N) laid out in a Randomized Complete Block Design with four replications. The study revealed that integrated management of one year residuals of the organic materials with inorganic N supported increased grain yield and was maximised with 7 5 t/ha biochar + 90 kg N/ha, 5 t/ha groundnut shell + 45 kg N/ha, 7.5 t/ha groundnut shell + 90 kg N/ha and 7.5 t/ha rice husk + 90 kg N/ha in the range of 3000 - 3600 kg/ha. Pearson correlation coefficients of grain yield with other traits exhibited robust relationships signifying strong impact of integrated soil fertility management of one year residual organic materials and N on maize production in the Guinea savannah. Grain yield prediction indicated treatments were best fitted in polynomials with 7.5 t/ha biochar + 90 kg N/ha for optimum grain yield.