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.

In the highlands of Ethiopia soil acidity is the limiting factor for crop production due to leaching effects of basic cations, nutrient loss by erosion, crop residue removal from farmland and other human induced factors. This study was carried out at Burie district to determine the effect of integrated use of lime and nitrogen fertilizer rate on yield and yield components of Maize in acidic nitisols. The treatments include lime (0 and 0.5 t ha -1 ) and nitrogen fertilizer (0, 100, 200, 300, and 400 kg ha -1 ). To fulfill the law of minimum, 200 kg ha -1 die ammonium phosphate (DAP) which is recommended rate of NPS (19% N, 38% P 2 O 5 and 7% S) fertilizer was used uniformly to all plots at the time of planting. The maize variety BH-661 was used as a test crop. The experiment was laid out in a randomized complete block design (RCBD) with ten treatments replicated three times. Yield and yield components of maize were collected and analyzed. The analysis of variance result revealed that, interaction effect of lime and N fertilizer reduced the tasseling period (88 days in the application of 0.5 t ha -1 lime with 100 kg ha -1 N to 85 days in combined use of 0.5 t ha -1 lime with 400 kg ha -1 N) and silking period from 91 days to 88 days. Grain yield was highly and positively correlated with AGDB (r=0.996) and HI (r=0.987). Grain yield of maize in the study area was increased from 5,550 kg ha -1 to 6,410.20 kg ha -1 (adjusted yield). Yield increment was 13.42%. The average maize yield in the region was 3,780 kg ha -1 but in the study area the adjusted yield was 6,410.20 kg ha -1 . As compared with regional maize yield it was increased by 40.3%. However, yield was highly and negatively correlated with DT (r=-0.957) and DS (r=-0.925). The maximum agronomic use efficiency of (3.76%) was from Treatment 10 (0.5 t ha -1 lime with 400 kg ha -1 N) than Treatment 7 (0.5 t ha -1 lime with 100 kg ha -1 N) of (3.16%). Based on the economic analysis, the net benefit value 47,701.04 Ethiopian Birr. Therefore, integrated application of 0.5 t ha -1 lime and 300 kg ha -1 Nitrogen fertilizer is economically reasonable and recommended to the farmers.