Soil organic carbon and crop yield under different soil amendments and cropping systems in the semi-deciduous forest zone of Ghana.

摘要

A field experiment to evaluate Soil Organic Carbon (SOC) and maize grain yield under different soil amendments and cropping systems was conducted in 2006 and 2007 at the Soil Research Institute, Kwadaso, Kumasi. The experiment was a split plot with three replications. The main plot factor (cropping systems) consisted of continuous maize, maize/soybean intercropping and maize cowpea rotation systems, the sub-plot (amendments) comprised of Poultry Manure (PM) at 4 t ha-1, poultry manure+chemical fertilizer (PM+CF) at 2 t ha-1 (PM)+45-30-30 kg ha-1 (NPK 15-15-15), Chemical Fertilizer (CF) at 90-60-60 kg ha-1 NPK 15-15-15 and a control (no amendment). Soil samples were taken at 21 and 84 days after amendment (DAA). Generally, PM+CF produced the highest range of SOC (1.14-1.37%). The least (0.98-1.28%) was recorded on the control plots. Plots amended with chemical fertilizer alone or in combination with poultry manure out-yielded the control in maize grain yield. Positive correlations between SOC at 84 DAA and maize grain yield were recorded in the major (r=0.70*) and minor (r=0.89**) rainy seasons of 2006 which established crop yield a function of SOC at harvest. Land equivalent ratios of sole maize (maize grown under continuous maize system) and maize intercropped with soybean were <1 which suggested more efficient utilization of land resources with sole maize cropping than intercropping maize with soybean.