【作者】 赵满兴；

【导师】 周建斌；

【作者基本信息】 西北农林科技大学 ， 植物营养学， 2004， 硕士

【摘要】 合理施用氮肥是提高小麦氮素利用效率及产量、改善小麦品质，保护环境的重要措施之一。多年来，国内外科学家们已进行了大量的研究，取得了不少成果。但应该看到，这些研究工作多集中在水肥条件供应充足的地区，对于旱地不同小麦品种对氮的吸收、转运，以及不同施氮水平下不同品种的氮素营养特性及诊断的研究尚待深入。本研究通过大田试验，研究了不同施氮量下不同冬小麦在生长过程中对氮素养分的吸收、累积和转移的效应，以及与小麦氮素营养相关的生长及生理指标与产量间的关系等。获得了以下主要结论：1 冬小麦群体干物质积累过程可分为三个不同的增长阶段，即指数增长期、直线增长期和缓慢增长期。施氮明显增加了干物质的积累。从施氮水平来看,随着施氮量的增加, 生物学产量和籽粒产量均增加,但当施氮量增加到一定程度（180kg/hm2）时,两者反而下降。不同品种相比,小偃22的生物学产量、籽粒产量与其它3个品种间都有显著差异,生物学产量和籽粒产量的大小排列次序为小偃22>小偃503>陕253>陕229。冬小麦产量构成因素中有效穗数对产量的贡献最大。2 拔节和开花期是冬小麦氮素累积的两个高峰期。叶子的累积量在拔节期达到最大,茎秆的累积量在开花期达到最大，叶子氮素转移率为80%左右,茎秆为40%-50%。品种间也有所不同,产量最高的小偃22叶片和茎秆的氮素转移率都高于其它品种。3 氮素利用效率和氮收获指数在不施氮时最高，随着施氮量的增加而降低，且施氮量间的差异显著。品种间氮收获指数无显著差异，但是氮素利用效率有显著差异。籽粒吸氮量在施氮量和品种间均有显著差异,其规律性与产量的一致。氮肥利用率、氮肥农学效率和氮肥生理效率随着施氮量的增加而降低。小偃22的氮肥效率显著高于其它3个小麦品种，说明小偃22对肥料氮的吸收、转化和利用能力最强。4 在拔节期，品种间的硝态氮、铵态氮、酰胺态氮和可溶性蛋白质都达到显著水平。施氮量、籽粒产量与硝态氮无显著相关性，而与铵态氮、酰胺态氮和可溶性蛋白质有较好的相关性，其中铵态氮和可溶性蛋白质与施氮量、籽粒产量的相关性最好，说明营养生长期间，叶片铵态氮、酰胺态氮、蛋白态氮供应充足，有利于籽粒产量的提高。拔节期是进行冬小麦营养诊断的最佳时期。5 叶绿素测定仪测定的SPAD值与小麦籽粒产量、生物学产量有很好的相关性，尤其以拔节期和开花期较高。不同施氮量下的SPAD值有明显的不同，施氮量为180 kg/hm2时，SPAD值达到最大。在同一施氮水平下，开花期的SPAD值都最高。拔节期之前冬小麦不同品种间 SPAD值的差异较小，拔节期以后差异较大，最大可达9.2个SPAD单位。小偃22在每个时期的SPAD值都最高，并且与陕253、陕229和小偃503均达到显<WP=6>著水平。可见， 小偃22与其它3个品种对氮素反应分属于不同类型，应根据不同品种类型建立相应的SPAD诊断指标。更多还原

【Abstract】 The suitable application of nitrogen fertilizer not only affects the yield and quality of wheat, but also the safty of the environment. And a lot of researches have been carried out in these aspects. However, many of the researches have concentrated on the areas with higher application of water and nutrients. There is limited information available on the uptakes, accumulations and translocation of nitrogen for the different varieties on dryland regions of China. This is also true for nitrogen diagnosis of winter wheat on dryland. Therefore, the field experiment was carried out to research the nitrogen nutrition status and diagnosis for various varieties of winter wheat on the dryland. The main results were shown as followings:(1) The curve of dry matter accumulation could be divided into three phases, i.e., exponential increasing phase, liner increasing phase and slowly increasing phase. Nitrogenous fertilizer increased the dry matter accumulation and grain yield of winter wheat. The dry matter and grain yield increased with the increase of N rate when the N rate is less than 180 kgN/hm2; they were decreased by higher nitrogen application. The biological and grain yield of Xiaoyan22 varieties were higher than that of the three other varieties; the dry matter and grain yield were in the following order, Xiaoyan22 >Xiaoyan503>Shaan253>Shaan229. Compared to the other grain components of winter wheat, the number of spike per ha had the biggest contribution to the yield.(2) The higher stages of N accumulation in the growth period were in Jointing stage and Anthesis stage. The highest N accumulation for leaf and stem was in Jointing stage and Anthesis stage, respectively. The N transportation rate of leaf was 80%. The N transportation rate of stem was 40-50%. Xianyan22 varieties had the highest N transportation of leaf and stem.(3) The application of nitrogen fertilizer had the significant effects on the N use efficiency and N harvest index. The N use efficiency and N harvest index was the highest for the treatment without N addition; and as the increasing N rate, there was a declining trend for N use efficiency and N harvest index. The N harvest index did not show obvious differences among different varieties, but the N use efficiency had difference. The recovery of nitrogen fertilizer, nitrogen agronomic efficiency and nitrogen physiological efficiency had declined with the increasing N rate. There was significant difference between Xiaoyan22 and the other varieties. <WP=8>(4) In Jointing stage, NO3--N, NH4+-N, NH2--N(amide nitrogen,NH2--N), Pro--N (soluble protein nitrogen, Pro--N) showed obvious differences among the different varieties. The significant correlationships were found between NH4+-N, NH2--N, Pro--N and yield and N rate. In vegetable growth stage, the yield increased with the levels of NH4+-N, NH2--N, Pro--N in the leaves of wheat. The optimum stage for nitrogen diagnosis was in the Jointing stage.(5) The significant correlationships were found between the readings (SPAD value) of chlorophyII meter and the yields of biomass and grain of winter wheat, especially at jointing stage and anthesis stage. The SPAD value and the application levels of nitrogen also had a close correlation, the SPAD value was the highest under 180 kg/hm2 of nitrogen rate. In the same application levels of nitrogen the SPAD value was the highest at anthesis stage. The variations of the SPAD value with the variety of wheat were less before jointing stage; and after jointing stage the variations of the SPAD value were increasing. The highest variation of the SPAD value was 9.2 SPAD unit for different varieties of winter wheat. Xiaoyan22 had the highest SPAD value at every stage, was higher than that of Shaan253 Shaan229 and Xiaoyan503. Therefore, Xiaoyan22 was a different type of cultivars. The variations of SPAD value with the variety of wheat is needed considering during the nitrogen diagnosis.更多还原