目录
摘要 Ⅲ
关键词 Ⅲ
Abstract Ⅳ
引言
引言 1
1 材料与方法 2
1.1 试验设计 2
1.2 测定项目与方法 2
1.2.1产量及产量构成因素 2
1.2.2 叶面积指数 3
1.2.3 叶绿素含量 3
1.2.4光合速率 3
1.2.5氮积累与转运及氮效率 3
1.2.6土壤铵硝态氮含量 3
1.2.7土壤脲酶、蛋白酶及蔗糖酶活性 3
1.2.8小麦根系生长 4
1.3数据处理与分析 4
2 结果与分析 4
2.1 产量及产量构成因素 4
2.2 叶面积指数 6
2.3 叶绿素含量 6
2.4 光合速率 7
2.5 氮积累与转运及氮效率 8
2.6 土壤铵硝态氮含量 9
2.7土壤脲酶、蛋白酶及蔗糖酶活性 11
2.8小麦根系生长 12
3讨论与小结 16
3.1 秸秆还田及氮肥运筹对小麦产量及土壤氮含量的影响 16
3.2 秸秆还田及氮肥运筹对小麦根系生长的影响 18
致谢 18
参考文献 18
水稻秸秆还田及氮肥运筹对土壤氮素供应及小麦根系生长的影响
摘要
秸秆还田后秸秆养分释放可以显著提高土壤肥力，而且可以减少秸秆焚烧带来的环境压力。然而秸秆还田后氮肥施用不明确，这将会影响土壤本身的氮素供应和小麦的根系生长。因此本试验采用大田试验，设置秸秆还田（S）、秸秆不还田（N）两种处理，240kg N/hm2(N240)、180 kg N/hm2（N180）两个施氮量，常规基施（L0）、3叶期施（L3）两个施氮时期，研究了水稻秸秆还田及氮肥运筹对土壤氮素供应及小麦根系生长的影响。结果表明，秸秆还田处理提高了产量及氮素利用效率，且通过减氮及基肥后移处理氮素利用效率的提高更为显著，秸秆还田通过增强土壤供氮能力和小麦氮同化能力来增加小麦花前氮素积累，同时促进了开花期氮素向 *51今日免费论文网|www.51jrft.com +Q: &351916072& 
叶片的分配和花后氮素转运，从而提高了小麦氮素利用效率；通过促进花后光合能力提高了干物质积累，提高了产量。秸秆还田促进了小麦花前060cm土层根系生长，从而提高了根系生物量并改善了根系形态，并提高了根系活力，有利于增加肥料氮吸收，而氮肥减量后移之后，显著提高了氮素利用效率。
EFFECTS OF RICE STRAW RETURNING AND NITROGEN APPLICATION ON SOIL NITROGEN SUPPLY AND ROOT GROWTH OF WHEAT
ABSTRACT
After returning straw to the field, the release of straw nutrients can significantly improve soil fertility and reduce the environmental pressure caused by straw burning. However, the application of nitrogen fertilizer is not clear after straw returning to the field, which will affect the nitrogen supply of the soil itself and the root growth of wheat. Therefore, the field experiment was used to study the effects of rice straw returning and nitrogen application on soil nitrogen supply and wheat root growth. The results showed that the straw returning treatment increased the yield and nitrogen use efficiency, and the nitrogen use efficiency increased more significantly through nitrogen reduction and base fertilizer post transfer treatment, and significantly reduced the amount of nitrogen residue and loss in the soil, but the yield was not significantly lower than the conventional fertilization. Straw returning increased the nitrogen accumulation before anthesis by enhancing the ability of soil nitrogen supply and wheat nitrogen assimilation. At the same time, it promoted the distribution of nitrogen from flowering stage to leaf and the transport of nitrogen after anthesis, so as to improve the nitrogen utilization efficiency of wheat. It also increased the dry matter accumulation and yield by promoting the photosynthetic ability after anthesis. Straw returning to the field promoted the root growth of 060cm soil layer before anthesis of wheat, thus increased the root biomass and improved the root morphology, which was conducive to increasing the absorption of fertilizer nitrogen. After the reduction of nitrogen, the residue and loss of fertilizer nitrogen were significantly reduced, and the reduction of top dressing nitrogen was higher than that of base fertilizer nitrogen, so the nitrogen utilization efficiency was significantly improved. At the same time, with the increase of sowing density, the number of wheat ears increased significantly, the decrease of grain number and grain weight was not significant, and the yield increased significantly; with the increase of root population, the density of root weight increased significantly, the absorption of nitrogen increased, the residue and loss of nitrogen decreased, and the efficiency of nitrogen absorption and utilization of wheat increased significantly.

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