Abstract: A field plot experiment was conducted to study the changes in the soil catalase, urease, invertase, and acid phosphatase activities as well as the relationships between these enzyme activities and soil nutrient contents in a tea plantation under straw mulching and white clover intercropping. Mulching and intercropping increased the contents of soil organic matter, total N, and available N and P significantly, and intercropping increased soil catalase and invertase activities while mulching increased soil phosphatase and urease activities obviously. Soil catalase, urease, invertase, and phosphatase activities all had significant positive correlations with the contents of soil organic matter, total N, and available N. Path component analysis indicated that the test enzyme activities were most directly related to soil organic matter or total N content, and principal component analysis showed that the weight of soil catalase, urease, invertase, and acid phosphatase activities in the first main component was 0.842, 0.937, 0.873, and 0.847, respectively. It was suggested that soil catalase, urease, invertase, and acid phosphatase activities could be used to evaluate the soil C and N fertility in hilly tea plantations.

Key words: Wheat, Root activity, Flag leaf, Senescence