Dynamic changes of soil enzyme activities during growth of corps under different tillage types and rotations

The dynamic changes of soil enzyme activities(soil nitrate reductase,urease,alkaline,neutral and acid phosphates phosphorus acid activity characteristics) during growth of corps in fluvo-aquic soil in Henan province were studied in field experiment by different tillage types(no-tillage(5 cm),rotary-tillage(15 cm),low-tillage(22 cm),deep-tillage(32 cm)),based on straws returned,as well as wheat-corn,wheat-soybean,wheat-peanut of three different rotations based on no-tillage.The results showed that the dynamic changes of soil enzyme activities is probably the same with the principle of crops growing during growth of crops;different tillage types had great impact on soil nitrate reductase activity,which had the highest activity of no-tillage;It didn't have obvious influence on the soil urease active in the earlier period of wheat growth,during wheat filling stage urease activeness is in turn: no-tillagerotary-tillageshallow-tillagedeep-tillage;It had little impact on phosphates activities.The effect on soil enzyme activities is different with crops,urease and nitrate reductase activities on the treatment of wheat-corn is higher than that on peanut and soybean,and three phosphates in wheat-peanut treatment is more active.