Study On The Effects Of Mixed Application Of Straw And Inorganic Fertilizers On The Fertility Of The Wheat-maize Cropping Production System

We studied on the effects of the combined application of fertilizer and straw on the nutrients of soil after harvest of each crop and the dynamic change of microbial biomass and soil enzyme crop in wheat-maize cropping production system (No. 4,5 crop),with a three-year experiment , in Henan .the main research results are as follows:1.Compared with the control, the crop yield significantly increased in all treatments. The crop yield of the combined application of fertilizer and straw have reduced in the first, compared with the single application of fertilizer.But the different were not significantly during different tilization practice from the second to the fifth,and so was in the applications of fertilizer and straw.2. Compared with the control, the nutrients of soil have increasing after the harvest, in the treatments of continuous fertilization,and the different was more significantly in the combined application of fertilizer and straw,with the average increase of about 6.02% -8.02% and 12.4% -14.8% annually. Compared with the control, the nutrients of soil were significantly increased ,in all treatments of fertilizer , and the treatment of the application of straw and fertilizer was more than the single application of fertilizer , after the five times of harvest. During the treatments of different amount of straw and fertilizer, the matter , avail P and avail K were increasing the consumption of straw, while the total nitrogen and avail N were more in the treatment of NPK+S, following by the treatment of NPK+1.5S and the last one the treatment of NPK+0.5S.3. The experimental results showed that content of NH4+-N,NO3--N significantly increased after dressing with nitrogen at wheat and corn in each fertilization treatments. The single application of chemical fertilizer had the largest increase, the application of half straw and fertilizer,and the whole amount of straw and fertilizer decreased ,but the application of Excess and fertilizer had the Increasing trend again. In the rotation system, the content of NH4+-N,NO3--N in the single application of chemical fertilizer was more than the control and the application of straw and fertilizer in each growth stage.4. With Continuouing single application of NPK ,there was a great positive effect on microbial biomass carbon and microbial biomass nitrogen; there was chemical fertilizer was a nasitive shortly effect on microbial biomass carbon and microbial biomass nitrogen after using NPK,but the straw cound reduce it.During a rotation period, soil microbial biomass carbon and nitrogen cound increased in the application of straw and fertilizer, but there were different during the different amount of straw,and the application of NPK+S was the best one. The effect on microbial biomass carbon and microbial biomass nitrogen was different during the various growing season of crops by the application of different amount of straw and fertilizer.5. Fertilization cound increase the activity of urease and phosphatase,but the application of straw and fertilizer was more than the single application of fertilizer . Considering the whole rotation period , the activity of phosphatase was increasing with the increase of the amount of straw,but the ctivity of urease was the best one in application of NPK+S. The effect on the activity of urease and phosphatase was different during the various growing season of crops by the application of different amount of straw and fertilizer.6.After there times returing straw to soil continuously, the amount of straw couldn,t affect the growth early of winter wheat, but more than the straw of NPK+S would affect adversely the early accumulation of dry matter; the application of straw and fertilizer would not affect to the early growth of corn, but more the amount of straw than NPK+1.5S would adversely affected the early growth of corn a.