Effect of Trifolium repens degradation on apple orchard soil enzyme activities in different regions

To determine the effects of white clover (Trifolium repens) degradation on soil enzyme activities in apple orchards, protease, urease, sucrase, and phosphatase activities in soil were detected after white clover was cut and buried in an apple orchard in Luochuan and Xunyi in Shaanxi province. Results show that the activities of soil enzymes, including protease, urease, sucrase, and phosphatase, significantly increased after the buried white clover was degraded (P < 0.05), except for phosphatase activity after 3 months of degradation and urease activity in Xunyi after 6 months of degradation. Increases in protease and phosphatase activities were greatest after 6 months of degradation. The effect of buried white clover degradation on the activity of soil enzymes varied spatially, with stronger effects observed in the Luochuan orchard. Correlational analyses of 4 enzyme activities showed a significant positive correlation between urease and sucrase. In conclusion, degradation of buried white clover can increase soil enzyme activities and improve physicochemical properties of soil. However, the effect of buried white clover is related to the planting apple site and white clover degradation time.