Effects of Integrated Use of Calcite and Inorganic Fertilizer on Soil Physicochemical Properties and Maize (Zea mays l.) Yield and, Economic Feasibility on the Nitisols of Northwestern Ethiopia
Abstract Background: Understanding the soil reaction (pH) is relevant for improving crop productivity. Soil acidity is one of the restraining factors to crop production in the highlands of Ethiopia. This study was carried out on the nitisols of Burie District to examine the effect of integrated use of Calcite and Nitrogen fertilizer on soil physico-chemical properties. Treatments were two levels of lime (0 and 0. 50 t ha-1) and five-level of nitrogen (0,100, 200, 300, and 400 kg ha-1). The experiment was laid out in randomized complete block design (RCBD) with ten treatments replicated three times. Before and after harvest, both disturbed and undisturbed soil samples were collected. Analysis of variance (ANOVA) and bivariate correlations was employed using SAS statistical package program version 9.0. After harvesting thirty soil samples were collected from each treatment and then ten composite soil samples within a block were arranged for laboratory analysis. Result: The result indicated that among the soil properties before planting the crop soil bulk density (BD), pH, organic carbon (OC), total nitrogen (TN), available P and CEC were 1.43g cm-3, 5.2 (strongly acidic), 1.32% (very low), 0.12% (low), 8.86 mg kg-1 (very low), and 19.57 cmolc kg-1 (medium), respectively. After harvesting, most of the surface physico-chemical properties except bulk density increased. The lowest soil BD was 1.21 g m-3 from plots treated with 0.5 t ha-1 lime and 400 kg ha-1 urea. The maximum soil pH (6.85) was obtained from plots treated with 400 kg ha-1 N and 0.5 t ha-1 lime. The maximum soil CEC (35.38 (cmolc kg-1) was obtained from plots treated with 400 kg ha-1 N and 0.5 t ha-1 lime. Level of lime, nitrogen fertilizer and interaction effects of lime and nitrogen fertilizer (L*N) significantly affected maize yield (p<0.001). Yield of maize have positive correlations with most soil physico-chemical properties but negative with BD (r=-0.543).The adjusted yield and net benefit was 6,410.20 kg ha-1 and 58,891.47 Ethiopian Birr (ETB), respectively.Conclusion: Inherent physicochemical properties of the soil is changed either by sole or combined use of lime and N fertilizer. Soils tilled with 0.5 t ha-1 lime and 138 kg ha-1 nitrogen was found in maximum net benefit. Residual long-term effects should be researched. Thus, liming should be given emphasis in acidic soil amelioration. Moreover, the government may facilitate the supply of calcite (CaCO3) and urea fertilizer to the farmers.