The Effects of Four Ratios of Organic to Inorganic Manures on Soil Physicochemical Properties and Maize Yield
This work was carried out to assess the potential effects of combined use of organic and inorganic fertilizers on the physicochemical properties of an ultisol and maize yield. The experiment was carried out first in the greenhouse and then evaluated in the field. In the greenhouse seven treatments namely 0.4t/ha N.P.K, 10t/ha pig dung, 0.2t/ha N.P.K +5t/ha pig dung, 0.25t/ha N.P.K + 2.5t/ha pig dung, 0.30t/ha N.P.K +1.25t/ha pig dung, 0.35t/ha N.P.K +0.65t/ha pig dung, control were evaluated using a Completely Randomized Design (CRD) replicated four times. The inorganic fertilizer used was NPK 15:15:15 while the organic manure was pig dung. The results indicated significant differences (P < 0.05) in plant height, leaf area and dry matter as well as in most of the soil physicochemical properties (P < 0.05). At the end of the greenhouse experiment, the best combined ratios of organic and inorganic fertilizers with the uncombined ones were used for field evaluation.there for the field evaluation these five treatments namely, N.P.K at 0.4t/ha, pig dung at 10t/ha, 0.25t/ha N.P.K + 2.5t/ha pig dung, 0.30t/ha N.P.K +1.25t/ha pig dung and control were involved using a Randomized Complete Block Design (RCBD) replicated three times. The results also indicated significant differences (P < 0.05) in the plant height, leaf area, dry matter, maize cob, grain yield and weight of the chaff with pig dung only (10t/ha) being the most superior in all the agronomic properties evaluated followed by one of the combined ratios of organic and inorganic fertilizer (0.25t/ha N.P.K + 2.5t/ha pig dung). From the study the use of only organic manure showed outstanding effects, but 0.25t/ha N.P.K + 2.5t/ha pig dung combination was a comparable alternative.
Keyword: Organic manure , compound fertilizer (NPK), soil physicochemical properties, maize yield.