Effects Of Straw Returning Methods On The Transformation Of Carbon And Nitrogen In The Rhizosphere Of Wheat And The Utilization Of Plant Nitrogen

Straw returning to the field is a widely used field straw management measure in the process of agricultural production in my country,and it has a positive effect on improving the physical and chemical properties of the soil and the growth and development of crops.As an important method of straw resource utilization,straw returning to the field can not only avoid resource waste but also reduce a series of environmental safety problems caused by incineration.Previous studies have shown that returning straw to the field has a significant impact on soil and crop growth.However,there are few studies on how different ways of returning straw to the field affect the process of carbon and nitrogen transformation in wheat rhizosphere soil and plant nitrogen utilization.This study took the rice-wheat rotation system in the middle and lower reaches of the Yangtze River as the research object,and set up three methods of returning to the field with rotary tillage,returning to the field with plowing and returning to the field with no-tillage.The influence of transformation,plant nitrogen uptake and yield and its constituent factors.In this paper,the effects of different ways of returning straw to the field on the transformation of wheat rhizosphere soil carbon and nitrogen and plant nitrogen utilization were studied from the aspects of wheat rhizosphere soil carbon and nitrogen content,functional enzyme activities,wheat nitrogen use efficiency,yield and yield composition.To explore the response characteristics of rhizosphere soil carbon and nitrogen conversion process and wheat nitrogen absorption in each growth and development link to different straw returning methods,and provide theoretical basis for improving wheat nitrogen use efficiency and promoting yield and income.1.The effect of different ways of returning straw to the field on the transformation of carbon and nitrogen in wheat rhizosphere soilRotary tillage treatment has the lowest organic carbon content in the rhizosphere soil,and its soil rhizosphere stimulating effect is the largest;three different methods of returning to the field can significantly increase the cellulase activity of the rhizosphere soil;no-tillage and rotary tillage Can significantly increase the activity of polyphenol oxidase,and return to the field significantly reduce the activity of polyphenol oxidase;the peroxidase activity of the straw returning treatment is higher than that of the straw removal treatment,showing a significant difference between no-tillage and rotary tillage Returning straw to the field can increase the activity of soilβ-glucosidase;with the increase of cellulase,polyphenol oxidase and peroxidase activities,the organic carbon content in the rhizosphere soil shows a downward trend.Returning to the field with rotary tillage and returning to the field significantly increase the total nitrogen content of the soil;returning to the field with no-tillage and returning to the field with rotary tillage can significantly increase the content of soil nitrate nitrogen;the rhizosphere activity of wheat can promote the accumulation of ammonium nitrogen in the soil;the roots of wheat International activities can inhibit soil denitrification enzyme activity.In the treatment with rhizosphere activity,the soil denitrification enzyme activity of no-tillage returning to field and plowing to field increased,while that of rotary tillage to field decreased.The rhizosphere activity of wheat can increase the soil nitrification potential.Compared with straw removal,the soil nitrification potential of no-tillage and plowing to the field showed a significant decline,while the nitrification potential of rotary tillage to the field increased significantly In addition,returning straw to the field with rotary tillage significantly increases the net mineralization rate of soil nitrogen.Rhizosphere activity helps to increase soil C/NO₃^-,and the C/NO₃^-of no-tillage returning to the field and rotary tillage returning to the field decreased significantly compared with its straw removal treatment.2.The effect of different ways of returning straw to the field on nitrogen absorption in the above-ground part of wheat in different growth periodsRotary tillage and plowing-to-field treatments can significantly increase the above-ground biomass and nitrogen content at the booting stage of wheat;at the booting stage,the nitrogen concentration of the rotary tillage-to-field panicle is lower than the other two farming methods,but the stem and leaf nitrogen concentration is high Compared with the other two treatments,the total nitrogen content of a single plant of wheat is also higher than that of the other two treatments;at the maturity stage,the nitrogen content of a single plant of wheat grains,glumes,stems and leaves under rotary tillage is higher than the other two treatments.Return to the field.The R_N of no-tillage to field and plowing to field showed a decreasing trend,and the U_N of rotary tillage to field was higher than that of the other two tillage methods;E_N,g and C_N,g of plowing to field were higher than that of rotary tilling to field and no-tillage The return to the field is high;the NUE of the rotary tillage straw returning to the field is higher than other tillage treatments.3.The effect of different ways of returning straw to the field on wheat yieldPlowing and returning to the field are beneficial to increase the number of wheat spikes and thousand-grain weight;the actual and theoretical yields of plowing and returning to the field both show a significant increase trend.Straw returning to the field can increase the wheat harvest index under different tillage methods.There are significant differences between tillage and tillage treatments.