EFFECTS OF LONG-TERM LOCATED FERTILIZATION ON SOIL ENZYMATIC ACTIVITIES FOR WHEAT-MAIZE INTERCROPPING IN IRRIGATED DESERT SOILS

In this study,soil enzymatic activities for wheat-maize intercropping in 26th year long-term located fertilization for irrigated desert soils were measured and analyzed to determine linetic variations of enzymatic activities and correlations among soil enzymatic activities under long-term located fertilization.results showed that the activities of soil catalase,invertase and alkaline phosphatase in 0～20cm soil layer increased with wheat and maize growing and reached the maximae during wheat jointing stage and filling stage,then the activities reduced after wheat filling stage.While the urease activity changed as M curve and reached 2 peaks at wheat jointing stage and maize maturing stage.Soil enzymatic activities increased obviously after application of different fertilizers.The activities of soil catalase increased by 5.7%～6.4%,urease increased by 25.1%～80.0%,and alkaline phosphatase by 25.2%～68.7% compared.The invertase activity increased by 71.5%～89.8% with single application of green manure and combined application of green manure with N fertilizers.The effects on soil enzymatic activities of combined application were more significant than single application.Positive correlations were significant between the catalase and invertase activity,the invertase and urease activity,urease and alkaline phosphatase activity;while the correlation were not significant between the catalase and urease activity,the catalase and alkaline phosphatase activity,the invertase and alkaline phosphatase activity.