Study On Ecological Effect Of Winter Wheat Mulched By Straw In Guanzhong Area

Crop stalks (CSS) are by-products of agricultural production, its unreasonable use will cause a huge waste of resources and environmental pollution. According to the current utilization situation of agricultural water resources and straw resources in the middle of Shaanxi province, taking corn stalks as cover materials, by studying the changes of soil temperature, moisture, nutrients microorganism and crop yield of winter wheat crop under different mulching quantity of corn stalk, this thesis discusses the comprehensive effect of straw mulching in increasing crop yields, promoting the soil fertility and improving soil conditions of hydro-ecological, providing theoretical basis and production guidance for reasonable use of straw resources and seeking effective drought-resistant and drought-resisting technology in the arid and semi-arid areas. Research results have very important theoretical and practical significance to increase farmers' income, guarantee the food security, protect the rural ecological environment, and build a resource-conserving and environment-friendly society. The following results were obtained through this research:(1)Straw mulching treatment technology has a significant regulatory function on soil temperature during the whole growth period of winter wheat. In the whole growth period of winter wheat, for each treatment of straw mulching:0～10cm,10～20cm soil layer, soil temperature is higher than the comparison; Along with the increase of straw mulching quantity, for each soil layer, the daily maximum and average temperature luffing are decreased; After straw mulching treatment, at 8:00 in morning. and 20:00 in the night, the order of soil temperature of 0～20cm soil layer is as follows:treatment 4> treatment 3> treatment 2> treatment 1. at 14:00 in the afternoon, the order of soil temperature of 0-20cm soil layer is as follows:treatment 1> treatment 2> treatment 3> treatment 4.(2) straw mulching treatment technology in farmland soil has very good effect on water storage, soil moisture. After wheat harvest, for each treatment of straw mulching, the average water content of 0～90cm soil is higher than the comparison. The average water content of soil in treatment 3 is up to 22.53%,5.6% higher than the comparison; For each treatment, the order of average water content of the soil in 0～160cm soil layer is as follows:treatment 3> treatment 4> treatment 2> treatment 1.(3) Straw mulching treatment increases the content of soil organic matter and available nutrient significantly. In 0～20cm soil layer, compared with the comparison, the content of organic matter respectively increases 7.3%,9.1%,11.1%; The content of soil available nitrogen respectively increases 1.6 mg/kg,2.7 mg/kg,4.0 mg/kg; The content of soil available p respectively increases 2.96 mg/kg,4.67 mg/kg,7.3 mg/kg; The content of soil available K respectively increases 19mg/kg,45mg/kg, and 49mg/kg.(4) Straw mulching treatment increases the amount of three bacteria significantly. In the same treatment, at different stages the order of the amount of soil bacterium is:after harvest> jointing stage> booting stage> before planting; In the same growth period, with the increase of straw mulching quantity, the amount of soil actinomycetes increases, For the same treatment, with the gradual growth period of winter wheat, the order of the amount of soil fungus is:after harvest> booting stage> jointing stage> before planting.(5) Straw mulching treatment increased winter wheat yield significantly. After tillering stage of winter wheat, the growth of each treatment of straw mulching is superior to that of the comparison, and straw mulching treatment makes each growth period of winter wheat delay 2～3 days. Wheat in treatment 3 grows best in each growth period, plant height, leaf area index, the biomass above ground are all the biggest; Along with the increase of straw mulching quantity, compared with the comparison, the output of treatment 2,3,4 increased 11.8%,27.00%,13.4% respectively; After straw mulching treatment, the net income of treatment 3 is 843.4yuan/hm2 higher than the comparison.(6) The comprehensive effect of straw mulching on the ecological factors indicates that, the best quantity of corn straw mulching is 6000kg/hm2 in the middle areas.