Effect Of Returning Straw Into Field On The Soil Aggregates Nutrients,organic Carbon Components

Xinjiang is the largest cotton planting region in China, the large of continuous cropping area, long period of continuous cropping, the prominent problem of continuous cropping. The straw can not only improve and ease the long-term continuous cropping of cotton continuous cropping obstacles arising problems, but also improve soil physical and chemical properties, soil nutrients and fertility. Therefore, In this study, the long-term continuous cropping of cotton locate a testing ground for the study of soil. First,carry out the study of soil water stable aggregates structure distribution of oasis at straw returning and long-term continuous cropping conditions. Reveal the effects of long-term continuous cropping cotton field straw water stable aggregates in structural stability. Second, through research and analysis at of oasis straw and long-term continuous cropping cotton field water stable organic carbon fractions and soil nutrient variation. Straw to investigate the soil quality of the soil cotton field. Oasis cotton straw for the rational use of technology to improve cotton field soil fertility and achieve scientific theory provide sustainable use of resources and guidance to regional agricultural development. Test results are as follows:1. Long-term continuous cropping of cotton mainly 1 ~ 0.25 mm, <0.053 mm diameter of water-stable aggregates. Straw processing 1 ~0.25 mm particle size aggregates with increasing continuous cropping increases, <0.053 mm diameter of water-stable aggregates with increasing continuous cropping decreased.No straw processing and returning straw showed the opposite trend. Description straw could improve large aggregates term continuous cropping cotton field 1 ~ 0.25 mm particle size, so that the small diameter water-stable aggregates to larger-diameter water-stable aggregates conversion.2. Long-term continuous cropping of cotton fields without straw, with the increase of continuous cropping years,> 0.25 mm water stable aggregates content, the value of the average weight diameter(MWD) and geometric mean diameter(GMD) is reduced, increasing the aggregate branches dimension, thereby reducing the aggregate stability. Stalk result contrary, it explained straw to improve the stability Cropping Cotton Soil aggregates, improve soil structure, increase soil erosion resistance, easing long-term adverse effects of continuous cropping on soil physical properties generated.3. In the straw processing under continuous cropping cotton field diameter of each water-stable aggregates of organic carbon and nitrogen with increasing continuous cropping increases; no straw treatment contrary.Total phosphorus, total potassium content less affected by changes in particle size. 1~0.25 mm particle diameter of water-stable aggregates the highest body of the nutrients in the soil nutrient contribution to the overall rate of 37.5% ~61.9%, followed by <0.053 mm aggregate 13.7%~33.9%, straw processing, 1~0.25 mm particle aggregates on soil nutrient contribution rate increases even cropping increases; 0.25~0.053 mm and <0.053 mm diameter aggregates on soil nutrient contribution rate increases even as the number of years gradually reduce.4. Straw improve the long-term continuous cropping cotton field of heavy organic carbon and Labile oxidize organic carbon content in soil aggregates, and with the continuous cropping to increase aggregate heavy organic carbon and Labile oxidize organic carbon content increased. At early straw aggregates heavy organic carbon mainly in micro-aggregates, the light fraction organic carbon mainly in large aggregates,with the continuous cropping to increase aggregate heavy organic carbon accumulation in the large aggregates, light fraction organic carbon content decreased. Labile oxidation organic carbon is mainly concentrated in large aggregates.