Effects Of Straw Returning Methods And Quantities On Organic Carbon And Nitrogen Components In Brown Earth And The Growth Of Maize

In order to rationally utilize straw resources and solve the difficulty of large output straw returning in the northern china,at the same time,under the conditions of straw not rotten returning and rotten returning and semi-and full returning combined with positioning test,it was still insufficient to explore the similarities and differences of response of organic carbon,nitrogen components in soil and maize growth status,to provide further experimental data for solving the problems of straw returning measures suitable for popularization in Northeast Cold Spring Maize.We observed the effects of different methods(rotten and not rotten)and quantities(semi-and full-returning)of maize straw application of soil samples organic carbon and nitrogen content and its components from different fertilization treatments(0-20 cm),through a field experiment treatments at the positioning test station of Brown earth in Shenyang Agricultural University as the research area.Meanwhile,maize samples were collected to analyze the growth status of maize at different growth stages,and the economic yield of maize was measured during ripening stage.It was a great significance to improve soil carbon and nitrogen levels,promote the feasibility and rationality utilization of straw returned to the field and the fertility of brown soil reasonably and extensively.The main conclusions were as follows:(1)Under the experimental conditions,straw returning in different methods and quantities could increase the content of soil total organic carbon and nitrogen during the growth period of maize.The range of increase was 11.49% ~ 39.71% and 6.74% ~ 32.89% respectively.The effect of rotten returning straw was more significant than that of not-rotten returning straw.Among them,the total carbon and total nitrogen content of brown earth increased by 39.71% and 32.89% respectively.(2)Straw returning in different methods and quantities can increase the activity index of soil organic carbon and nitrogen,the range of increase is 15.51% ~ 51.05% and 4.70% ~ 25.15% respectively,and the effect of straw returning to the field alone was better than that of straw and chemical fertilizer combined application.Among them,the effect of not-rotten and full-returning straw to the field on the increase of soil organic carbon activity index was the best,the increase range was 51.05%.The effect of rotten and half-returning straw to the field on the increase of soil organic nitrogen activity index was the best,the increase range was 25.15%.(3)The content of microbial biomass carbon,nitrogen and soluble organic carbon and nitrogen in brown earth could be increased by returning straw in different ways and quantities(except the not-rotten and full-returning straw).The effect of the not-rotten and semi-returning straw combined with chemical fertilizer was better than that of other treatments,and the increase ranges were 186.27%,194.14%,210.95% and 161.53% respectively.(4)Straw returning in different ways and quantities(except the not-rotten and full-returning straw)can increase the stem height,stem diameter and the biomass of all parts above ground of maize,and the effect of the not-rotten and semi-returning straw on the biomass of all parts above ground of spring maize was the most significant.(5)Under the condition of straw returning to the field alone,the economic yield of maize returned from rotten straw was higher than that from not-rotten returning straw.And under the combination of returning straw and chemical fertilizer,the economic yield of maize returned from not-rotten straw was higher than that from rotten returning straw,and the effect of semi-returning straw on the economic yield of maize was better than that of full-returning straw.Among them,the economic yield of the treatment of the not-rotten and semi-returning straw combined with chemical fertilizer was the largest,which was 10.10 t·hm-2.In summary,under the experimental conditions,the not-rotten and semi-returning straw combined with chemical fertilizer was the most suitable measure to implement straw returning to the field in the Northeast Cold Spring Maize area.