Soil Chemical Property Variation under Different Conservation Agriculture Practices, in Bako Tibe District, West Shoa, Ethiopia

Conservation agriculture is claimed to be one of the solutions for the problems of poor agricultural productivity in sub-Saharan countries. The impact of conservation agriculture depends on environmental factors such as slope, vegetation, soil type, rain fall pattern and intended crops. This study was conducted from 2013 to 2014 with the objective of assessing the impact of conservation agriculture practices on soil chemical properties. Five main treatments were selected for the study: Monocropping (maize) without crop residue, Monocropping (maize) with crop residue, Crop rotation (maize and haricot bean) with crop residue, Intercropping (Haricot bean with maize) with crop residue and a grazing land as a control. A Randomized complete block design with four replications was used. A total of 40 composite soil samples (4 replication * 5 treatments * 2 soil depth) were collected and analysed for selected soil chemical properties. Results showed that soils in the study area were moderately acidic, and contained medium level of available phosphorus (AP) (7.33±0.58 mg/kg), but low concentration of total N (0.176±0.02%). Soil pH, soil organic carbon (SOC), total nitrogen (TN), C/N, and AP did not significantly differ (p=0.958, p=0.998, p=0.219, p=0.140 and 0.568) respectively, among the treatments following the four year of conservation agricutural practices. Thus, conservation agriculture has little effect on soil properties in short term, but it may take longer time to influence on different soil chemical properties in the study area.