Study On The Effect Of Returning Rice-straw To Soil On Trend Of Microbe And Enzyme In Double Cropping Rice Soil

Rice-straw was rich with nutrient elements for crop to use and was an excellent natural resource for human kinds. The soil quality could be improved by returning rice-straw to soil.At the same time,the crop could grow well and produce much biomass when the soil was covered with straw.In order to probe into the effect of returning quantity of rice-straw to soil on biological character in soil and provide scientific proof for reasonable applying rice-straw to soil,the studies on effect rule of tillage with 0%,33%,67%,100% quantity rice-straw to soil on the microbial quantity,microbial activity,soil rice-straw-decomposing enzyme; ammonification and nitrification in late paddy soil and the next early paddy soil were conducted.The results showed that:During the stage of late-rice growth , except that the quantities of actinomycetes in soil decreased all along, the quantities of aerobic bacteria, anaerobic bacteria and fungi increased in the first stage,and decreased in the middle stage slowly and in the late stage sharply.The microbial activity in soil increased to the largest sharply and decreased sharply in the middle stage, then increased slowly during the late stage. The changing rule of xylanase activity in soil was the same as the aerobic bacteria in soil. Celluase activity in soil decreased during the first stage and to the highest during middle stage, and then decreased sharply during the late stage.Protease and catalase activity in soil decreased all along.Urease activity in soil increased in the first stage and decreased in the middile stage,in the late stage it increased again.The changing rule of ammonification was the same as the quantities of actinomycetes. The changing rule of nitrification in late paddy soil was to increase during the first stage and to the highest during the middle stage , and then decreased during the late stage. With increasing the returning quantities of rice-straw to soil ,the changing rule of biological character in paddy soil was more and more sharp. According to the results, returning...