Studies On Nitrogen Fertilization Managements Incorporation With Straw-returning Manner Of Winter Wheat-summer Maize Rotation System

The anniversary field experiment was conducted to study the effects of nitrogen fertilization managements incorporation with straw-returning manner for winter wheat-summer maize rotation system on yield,growing development,photosynthetic characters,nitrogen metabolism,soil physical and chemical properties and enzymatic activity in the Yuncheng and Xuchang,Defined the appropriate way of nitrogen fertilization managements incorporation with straw-returning manner for winter wheat-summer maize rotation system,to provide theory and technology for appropriate way of straw-returning and decline nitrogen fertilizer of winter wheat-summer maize rotation system.The main results were as follows:1?The yield significantly increased with nitrogen fertilizer on winter wheat and summer maize in two sites,The yield respectively increased 13.14%~16.70% and23.04%~27.58% of straw returned ploughing to field,15.53%~16.67% and23.97%~25.65% of straw returned rotary tillage to field,The yield of straw returned ploughing to field respectively increased 2.22%~6.42% and 1.65%~6.47% than rotary tillage.The nitrogen fertilizer utilization efficiency,nitrogen efficiency of agriculture respectively was 24.78%~30.81%,2.93~5.33kg? kg-1 and 18.75%~25.69%,4.67~7.04kg? kg-1 in two sites,and with the increase of nitrogen application had certain decrease trend.2?Nitrogen application were significantly increased the nitrate reductase activity?glutamine synthetase activity,soluble protein content,SPAD of functional leaves of jointing stage and flowering stages of winter wheat and silking stage and filling stage of summer maize,and photosynthetic efficiency of functional leaves of flowering stages of winter wheat,and had promoted uptook of NPK nutrient,and significantly increased soil urease activity?sucrase activity of harvest stage.The photosyntheticefficiency,enzyme activity of nitrogen metabolism,nitrogen efficiency,soil enzyme activity of straw returned ploughing to field were more than rotary tillage.3 ? Winter wheat straw returned with ploughing and rotary tillage are significantly reduced the soil bulk density in the layer of 0-30 cm,and straw returning with ploughing was lower than rotary tillage of summer maize,and has an increased trend with the increase of soil depth deepened.Application nitrogen fertilizer decreased the less than 53 mm graded aggregate water stability and increased the0.25-0.5mm graded aggregate water stability,content of soil organic carbon and total nitrogen in the layer of 0-40 cm soil depth,and increased the content of inorganic nitrogen of harvest stage of winter wheat and summer maize,and straw returned ploughing to field more than rotary tillage.4 ? The straw returned with ploughing and once nitrogen application210kg? hm-2(60% release-controlled urea + 40% ordinary urea)had a good increase yield,and the fertilizer use efficiency,photosynthetic efficiency,carbon and nitrogen metabolism,enzyme activity of soil were higher of winter wheat-summer maize rotation system.