EFFECTS OF INDIGENOUS ORGANIC MATERIALS FOR SOIL FERTILITY RESTORATION ON PRODUCTIVITY OF MAIZE (Zea mays L.) IN THE GUINEA SAVANNAH ZONE

Abstract

A pot and field experiments were conducted to determine the optimum planting date after incorporation of organic materials and the effects of indigenous organic materials on maize grain yield and yield components. The pot experiment was a 4 × 5 factorial experiment consisting of 4 Organic materials: biochar, rice straw, rice husk and groundnut shells of weight 156.2 g and 5 days of incorporations of organic materials (7, 14, 21, 28 and 35). The experiment was laid out in a randomized complete block design and replicated 3 times with surface area of each pot being 0.0314 m2. The pot experiment results indicated that the parameters assessed were significantly influenced (p≤0.05) by the application of the organic materials and planting dates. Biochar and Groundnut Shells applications enhanced vigorous vegetative growth (plant height, leaf count) and were at par. Maximum total dry matter weight was recorded with Biochar and Groundnut Shells. 21, 28 and 35 days after incorporation of the organic materials gave the best performance in growth parameters and total dry matter weight. Optimum planting dates was observed at 21 days after incorporation of the different organic materials. The field trial was a 4×3×3+1 factorial experiment consisting of the same 4 organic materials as in the pot experiment at 2.5, 5 and 7.5 t ha-1 dry matter basis, 3 fertilizer grades (0-0-0 kg NPK ha-1, 45-30-30 kg NPK ha-1 (1/2 NPK) and 90-60-60kg NPK ha-1 (FNPK)) and a control (non-fertilized). It was laid in a randomized complete block design with 4 replications. Results showed that application of organic materials with and without inorganic fertilizer significantly increased maize productivity. Vigorous vegetative growth was observed with the application of 7.5 t/ha Biochar + FNPK, 7.5 t/ha Biochar + 1/2 NPK, 7.5 t/ha Groundnut Shells + FNPK, 7.5 t/ha Groundnut Shells + 1/2 NPK, 5 t/ha Biochar + FNPK, 5 t/ha Biochar + 1/2 NPK, 7.5 t/ha Rice Husk + FNPK, 7.5 t/ha Rice Husk + 1/2 NPK, 7.5 t/ha Rice Straw + FNPK and 7.5 t/ha Rice Straw + Y2 NPK. Applications of 7.5 t/ha Biochar + FNPK, 7.5 t/ha Biochar + Y2 NPK, 7.5 t/ha Groundnut Shells + FNPK, 7.5 t/ha Groundnut Shells + Y2 NPK, 5 t/ha Biochar + FNPK, 5 t/ha Biochar + Y2 NPK, 7.5 t/ha Rice Husk + FNPK, 7.5 t/ha Rice Husk + Y2 NPK, 7.5 t/ha Rice Straw + FNPK and 7.5 t/ha Rice Straw + Y2 NPK enhanced grain yield and yield components at harvest. The regression analysis showed that cob weight, 100 seed weight and stover weight at harvest determined grain yield. The soil amendments affected the soil pH, organic carbon content, the major soil nutrients (nitrogen, phosphorus and potassium) and the soil texture appreciably at harvest. All the organic amended treatments influenced soil productivity over the control and consequently enhanced higher maize yields. The organic nutrient management strategy fit into the status of the resource poor farmers in the Guinea savannah zone.