Impact of irrigated and non-irrigated cropping systems on soil physicochemical properties in a small-scale irrigation farming system in Eastern Uganda

This study evaluated the impact of irrigation and cropping on soil physicochemical properties at Kyekide small scale irrigation farm in Jinja district, eastern Uganda. Treatments included Land-use systems under perennial and annual cropping with and without irrigation for over 20 years. The hypothesis was that there were insignificant differences in physicochemical properties of the soil under irrigated and non-irrigated cropping systems. Soil physical properties except hydraulic conductivity was not significantly different with irrigation and cropping. The pH of the soils ranged from moderately acidic to neutral pH (5.17-7.40), with irrigated soils tending to be more neutral than non-irrigated soils. SOM content was higher in the irrigated soils and perennial soils than in the non-irrigated and annual soils. The soils were moderately deficient in N and severely deficient in P (mean values =0.175% N and 1.183mg kg-1 P) compared with the critical of 0.2% and 15 mg kg-1, respectively. Irrigated soils had a significantly higher Na+ content than non-irrigated soils, with a mean value of 2.985cmol/kg. The K+, Ca2+, and Mg2+ contents were higher in irrigated and perennial soils than non-irrigated and annual soils. The study suggested monitoring the soils under an irrigation scheme to prevent degradation due to increased salt accumulation or chemical fertility decline. Overall, monitoring of soil quality is vital in irrigation schemes to monitor the impacts of water on the environment.