EFFECTS OF SAWDUST AND ORGANOMINERAL FERTILIZER AND THEIR RESIDUAL EFFECT ON THE YIELD OF MAIZE ON DEGRADED SOIL

Conventional mineral fertilizer alone cannot sustain arable crop production in soil which top layer has been eroded hence it is necessary to employ the application of organic base fertilizer. A greenhouse experiment was conducted to investigate the effects of sawdust, organomineral fertilizer and their residual effects on the growth and yield of maize. Organomineral fertilizer is the combination of organic manure and mineral fertilizer. Simulated degraded soil was used and the experimental design was a 2 x 2 x 3 factorial in a completely randomized design with three replicates. The factors investigated were: two levels of organomineral fertilizer (with and without), two levels of soil amendment (with and without sawdust) and three levels of application methods. The methods of organomineral fertilizer used were ring, subsurface and mixed methods. The amendment of soil to sawdust was ratio 1: 1 by volume. The growth and yield of maize was significantly (p = 0.05) higher in non–amended soil with OMF under different application methods compared to soil amended with sawdust with or without OMF application. Ring method of application of OMF in non–amended soil significantly increased the growth and yield of maize compared to other methods of OMF application. The residual effect of OMF and sawdust on the growth and yield of maize was significantly higher in non–amended soil with OMF under different application methods compared to soil amended with sawdust. Addition of sawdust to soil does not improve the growth and yield of maize with or without OMF and under different application methods. Organomineral fertilizer using ring and subsurface application methods has a beneficial effect in improving the growth and yield of maize in degraded soil where the top layer has been eroded.