【作者】 沙之敏；

【导师】 边秀举； 何萍；

【作者基本信息】 河北农业大学 ， 园林植物与观赏园艺， 2010， 硕士

【摘要】 过量施用氮肥是华北地区冬小麦-夏玉米粮食种植体系存在的主要问题。研究华北地区主栽作物品种的生物量和氮素的积累规律,并根据作物阶段氮素需求结合土壤起始无机氮和本底养分供应来施用氮肥,对于保证作物产量、提高肥料利用率、降低环境污染都有重要的意义。因此,本研究采用冬小麦衡观35和夏玉米郑单958为材料进行田间试验,结合土壤测试和植株分析,比较不同氮肥管理措施在冬小麦和夏玉米上的应用效果,并探索科学的氮素同步调控方法。本文取得的主要进展如下:1通过对不同肥力土壤冬小麦干物质和氮素积累规律,发现冬小麦干物质积累的高峰出现在拔节-抽穗和抽穗-灌浆期,氮素积累的高峰出现在拔节-抽穗期。基施氮肥能够提高冬小麦生育期干物质和氮的最大积累速率,提早最大速率出现的时间。2衡水试验点土壤Nmin含量、本底氮素供应量均高于辛集,属于高肥力试验点,基肥的施用与否对返青前冬小麦生物量和氮素积累没有影响,冬小麦季氮素的损失主要发生在拔节前,因此减少基肥施用,拔节后分次适量追施氮肥有利于增加冬小麦的产量、提高氮肥利用率,并且减少氮素的损失。3冬小麦关键生育期叶片SPAD值与叶片氮素含量之间有显著或极显著的相关关系,且生育后期的相关性高于前期。SPAD值与Na的相关性高于Ndw。用SPAD值可以反映冬小麦的氮素状况。4夏玉米干物质和氮素积累的高峰均出现在拔节-抽雄期,随着施氮量的增加,玉米生育期干物质和氮素的最大积累速率增加,而随着基肥施用量的增加,最大积累速率出现的时间提前。5衡水试验点夏玉米季土壤Nmin含量、本底氮素供应量均高于辛集试验点。夏玉米季分次施氮能够提高产量和氮素利用率,还可以降低收获后土壤中Nmin的残留及其表观损失,使玉米生育期养分吸收和土壤供应同步。与农民习惯施肥相比,分次施氮能够减少25%-85%的肥料用量。不同的土壤肥力和质地显著影响氮肥的施用效果,因此,对氮肥应该采用作物养分阶段需求结合土壤供肥能力分区管理模式。6夏玉米关键生育期叶片SPAD值与叶片氮素含量之间有显著或极显著的相关关系。SPAD值与Na的相关性高于Ndw,用SPAD值可以反映夏玉米的氮素状况。更多还原

【Abstract】 Excessive application of N fertilizer is the main problem of winter wheat and summer maize cropping system in North China Plain. It is important to ensure the crop yield, increase nitrogen use efficiency and reduce environmental pollution by studying the laws of biomass and nitrogen accumulation of the main cultivars in North China and applying nitrogen fertilizer according to the crop demand in different stages combined with the content of soil initial inorganic nitrogen and indigenous nitrogen supply (INS). Therefore, field experiments were conducted with the materials of winter-wheat Hengguan 35 and summer maize Zhengdan 958. Combined with soil testing and plant analysis, the application effect on winter wheat and summer maize with different nitrogen management practices were compared and the scientific methods of nitrogen synchronous regulation were explored. The major findings are as following:1 The laws of dry matter and nitrogen accumulation of winter wheat in different fertility soils were revealed. The findings showed that the peak of dry matter accumulation of winter wheat was from jointing to heading and from heading to filling, while the peak of nitrogen accumulation was found to be from jointing to heading. The highest dry matter and N accumulation rates in different stages of winter wheat could be improved and its earlier occurring could be achieved with basal nitrogen fertilizer.2 The soil Nmin content and indigenous nitrogen supply of Hengshui experiment site, which belongs to high fertility site, were higher than that of Xinji experiment site. There is no significant effect to biomass and nitrogen accumulation of winter wheat before regreening with basal nitrogen fertilizer or not. The loss of nitrogen in winter wheat was mainly occurred before jointing. Therefore it would be beneficial to improve wheat yield, increase nitrogen use efficiency and reducing the loss of nitrogen by topdressing properly after jointing.3 A significant or highly significant relationship was found between leaf SPAD readings of key growth stages in winter wheat and the leaf nitrogen content, and the correlation in late growth stage was higher than that of prophase. The correlation between SPAD reading and Na was higher than Ndw. Therefore the status of plant nitrogen could be reflected by SPAD readings.4 The peak of dry matter and nitrogen accumulation of summer maize was from jointing to heading. The highest rates of dry matter and nitrogen accumulation in different growth stages of summer maize were increased with the amount of nitrogen. The occurrence of the highest accumulation rate would be achieved earlier with the increase of basal fertilizer.5 The soil Nmin content and indigenous nitrogen supply of Hengshui experiment site were higher than that of Xinji experiment site in summer maize season. Nitrogen fertilizer with split application can not only increase yield and nitrogen use efficiency, but also reduce the soil Nmin residual and its apparent loss, and synchronize N demand of maize in different growth stages and soil N supply. Compared with FFP (Farmers’Fertilizer Practice), 25%-85% amount of fertilizer could be saved by nitrogen fertilizer with split application. The nitrogen application effect could be significantly affected by the difference of soil fertility and texture. Therefore, regionalized N management should be adopted in nitrogen management practices combined with the demand of crop nutrient in different stages and soil supplying nutrient capacity.6 A significant or highly significant relationship was found between leaf SPAD readings of key growth stages in summer maize and the leaf nitrogen content. The correlation between SPAD readings and Na was higher than Ndw, therefore the status of plant nitrogen could be reflected by SPAD readings.更多还原