| The test was carried on in the Zaohe town of Suqian of Huaibei region of Jiangsu in 2005-2007, took the wheat as an object which is in the south of Huanghuai region after rice. In this district, two representative varieties, Huaimai19 (medium-gluten wheat) and Yannong19 (Strong gluten wheat) were chose as materials, six nitrogen levels was set up after rice in three kinds of high, middle and low different fertility levels field. This test had systematically studied nitrogen application rate on wheat grain yield and its composition, physical production index, the quality and the effect of nitrogen uptake and utilization etc, for the wheat high-yield, high-quality and high-efficiency production provides theory basis. The main result of study is as follows:1. There were prominent conic section relations among the nitrogen application rate and output at every fertility level. The appropriate nitrogen application rate which the high-yield wheat needed in the high, middle and low fertility, Huaimai19 respectively were 246.7kg·km-2,286.1kg·km-2,345.9kg·km-2; Yannong19 respectively were 247.9kg·km-2,292.6kg·km-2,349.4kg·km-2. Different fertility high-yield field of each growth stage had better crop quality properties: the reasonable tiller number, the suitable leaf area index, the higher dry matter accumulation after anthesis and the greater storage capacity of the crop. Because of the various factors in many aspects of material production of wheat, different fields which nitrogen application rate at high, middle and low fertility level all presented each relative maximum yield, and this kind of maximum yield improved notably with the increase of fertility, but the nitrogen application rat corresponding to maximum yield reduced correspondingly sequentially, as a result, in wheat production, different target yield and corresponding accurate nitrogen application rate should be made with the level of the fertility level.2. The grain density, thousand kernel weight and flour yield of wheat had prominent shouldering relevant relations with the nitrogen application rate at every fertility level, the coefficient correlation separately reached -0.9732,-0.9929,-0.9887.The grain density, thousand kernel weight and flour yield at low fertility were maximum t, while at high fertility were minimum; the grain protein content, wet gluten content and Sedimentation value improved notably with the increase of nitrogen application rate. The protein output presented the conic section relation with the nitrogen application rate on high, middle fertility, while presented the linear positive correlation relation with the nitrogen application rate on low fertility, and the protein output was the biggest on high fertility, but on low fertility was the smallest. The nitrogen application rate which supreme protein output needed in the high, medium and low fertility respectively were 270kg·hm-2,337.5kg·hm-2,405kg·hm-2;the wheat grain starch content and the component all presented the downward trend with the increase of nitrogen application rate at every fertility level. The starch RVA characteristic spectrum on middle fertility was superior to that on low fertility, while the starch RVA characteristic spectrum on low fertility was superior to that on high fertility. The wheat dough rheology parameter all presented the linear positive correlation relation with the nitrogen application rate at every fertility level, the valorimeter value on high fertility was higher than that on middle and low fertility.3. The amount of nitrogen sucked of wheat plants in each periods and the shifting amount of nitrogen among nutrition organs after anthesis presented prominent linear positive correlation relation with nitrogen application rate, which in high fertility field was higher than that in middle fertility field, and that in middle fertility field was higher than that in low fertility field. Plain net accumulation amount of nitrogen of the plant after anthesis and nitrogen use efficiency presented downward trend after rising first with the increase of nitrogen application rate, and showed the ascendant trend with the improvement of the fertility level. When nitrogen application rate was 135kg·hm-2, absorption efficiency of nitrogen and agricultural utilization ratio of the nitrogen were both the highest under every fertility condition. Because of the comprehensive functions of wheat nitrogen of factor in many aspects of absorbing and shifting etc., each treatment of nitrogen application rate at different fertility levels appeared relative supreme nitrogen use efficiency. But this kind of nitrogen use efficiency rose notably with the improvement of the fertility level, on the contrary, the corresponding nitrogen application rate what could achieve the supreme nitrogen use efficiency was relatively small on high fertility, the supreme nitrogen use efficiency of wheat under the high, middle and low fertility condition appeared in the treatments which nitrogen application rates were 202.5kg·hm-2, 270kg·hm-2, 337.5kg·hm-2 separately. Therefore, to obtain the high-efficient of nitrogen utilization in wheat production, different accurate nitrogen application rates should be made with the level of the fertility level.
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