Straw mulching with fertilizer nitrogen: An approach for improving crop yield, soil nutrients and enzyme activities

Field experiments were conducted to study soil properties, soil enzymes activities, water use efficiency (WUE) and crop productivity after six years of soya bean straw mulching in the semi-arid conditions of China. The experiment included four treatments: CK (Control), N (240 kg N ha(-1)), H (soya bean straw mulching at half rate 700 kg ha(-1) with 240 kg N ha(-1)) and F (soya bean straw mulching at full rate 1,400 kg ha(-1) with 240 kg N ha(-1)). Soil organic carbon (SOC), soil labile organic carbon (LOC), soil available N (AN), available P (AP) and enzyme activities were analysed after wheat harvesting in 2016 and 2017. Results show that straw amounts had positive effects on the soil fertility indices being higher for treatment F. The SOC, LOC, AN, AP and enzyme activities (i.e. saccharase, urease and alkaline phosphatase) were in the order of F > H > N > CK. High wheat grain yield and WUE were observed for F treatment. A total of six years mulching along with 240 kg ha(-1) nitrogen fertilizer application is sufficient for wheat yield stability and improving soil properties except urease activities in the semi-arid condition of China. However, the straw mulching amount should be further studied with minimum nitrogen fertilizer for an environment-friendly and effective approach for improving the soil biological properties with adequate crop production on a sustainable basis in the semi-arid region of China.