Effects of nitrogen and phosphorus management on soil enzyme activity, nutrient supply, and wheat yield

To explore the effects of nitrogen (N) and phosphorus (P) management at different growth stages on soil nutrient transformation, supply, and wheat yield formation, we conducted a field experiment at two sites of Longting (Kaifeng) and Dancheng (Zhoukou). With identical total N and P application rates, we designed four treatments with different N and P application frequencies: 50% basal, 50% jointing 2-split N + basal 1-split P (2N1P), 50% basal, 30% jointing, 20% anthesis 3-split N + basal 1-split P (3N1P), 50% basal, 50% jointing 2-split N + 70% basal, 30% jointing 2-split P (2N2P), and 50% basal, 30% jointing, 20% anthesis 3-split N + 70% basal, 30% jointing 2-split P (3N2P). We analyzed the impacts of these nitrogen and phosphorus management strategies on soil enzyme activities, soil nutrient, wheat dry matter accumulation, and grain yield. Compared with the 2N1P treatment, the 3N2P treatment significantly enhanced the activities of soil β-1,4-glucosidase and cellobiohydrolase during the wintering, jointing, and anthesis stages. In contrast, the 2N2P treatment significantly elevated the activities of soil leucine aminopeptidase and phosphatase during the jointing, anthesis, and maturity stages. The 3N2P treatment significantly increased soil available phosphorus content during the jointing and flowering stages, while the 2N2P treatment significantly increased soil available phosphorus content specifically during the anthesis stage. The 3N2P treatment significantly promoted dry matter accumulation during the anthesis and maturity stages, with an increase range of 14.3%-25.7%. Both the 2N2P and 3N2P treatments significantly improved wheat grain yield, with 3N2P treatment achieving higher yield increase of 7.8%-10.8%. In conclusion, the application of nitrogen fertilizer in two to three split doses and phosphorus fertilizer in two split doses, particularly 3N2P could enhance soil nutrient transformation and availability, promote pre- and post-anthesis dry matter accumulation in wheat, and thereby increase grain yield.