Profile Distributions and Relationships of Soil Hydrolytic Enzymes' Activities in the Irrigated Farming Sierozem under Different F ertilizations

This study examined the profile distribution and relationships of soil total nutrients' contents and the activities of intervase,urease and alkali-phosphatase in irrigated cultivation Sierozem under different fertilizer amendments in Semiarid Area of Northwest China.The results showed that the order of the activities of intervase,urease and alkali-phosphatase in different soil depths was 0-10 cm 10-20 cm 20-40 cm during the growing phase of wheat,and it was significantly different as for the soil enzymes' activities between different soil depths in most of the fertilizer treatments.The activities of soil intervase,urease and alkali-phosphatase were positively correlated with the contents of soil organic matter,total nitrogen and total phosphorus.There were significantly positive correlation among the activities of intervase,urease and alkali-phosphatase in soil.Generally,the activities of soil enzyme could be used to evaluate to the level of soil fertility.