中文摘要：

在黄土高原南部半湿润易旱区，以土垫旱耕人为土为供试土壤，进行大田试验，研究栽培模式和施氮对冬小麦灌浆过程中籽粒体积、粒重和含水量的影响。结果表明，籽粒体积随灌浆进程的变化符合一元二次方程，籽粒体积在灌浆起始阶段快速增长，之后缓慢增长至最大值，后期快速下降；对不同灌浆期籽粒体积和最大籽粒体积，小偃22大于小偃503，不同栽培模式其大小顺序为：集雨面栽培〉全程覆膜〉常规栽培，施氮对其影响不显著，各处理达到最大籽粒体积时间变化在24．3～25．7d间，差异不大。各处理粒重均呈“S”型变化趋势，符合Logistic生长模型；小偃22的最大粒重大于小偃503；而不同栽培模式的最大粒重表现为：地膜覆盖栽培〉常规栽培、集雨面栽培；施氮对小偃503最大粒重有促进作用，而对小偃22表现出一定抑制作用。从总体上看，小偃503的灌浆速率大于小偃22；常规栽培和集雨面栽培的灌浆速率大于覆膜栽培；施氮对灌浆速率的影响与对粒重的影响相反。不同小麦品种粒重的差异与灌浆进程有关，在灌浆前期小偃22与小偃503粒重差异不明显，在中后期，小偃22与小偃503粒重差异逐渐增大，灌浆结束时小偃22粒重显著大于小偃503。从收获时粒重和全灌浆期平均粒重看，均以集雨面栽培最大，全程覆膜栽培次之，常规栽培最小，与最大粒重有所不同。籽粒含水量随灌浆过程推进几乎均呈直线下降，但小偃22籽粒含水量大于小偃503；栽培模式和施氮对籽粒含水量影响较小。小麦粒重与籽粒体积和含水量间存在显著或极显著线性相关关系。

英文摘要：

A field experiment was conducted on the Earth-Cumulic-Orthic Anthrosols in south Loess Plateau, to study the effect of nitrogen, cultivars and cultivation model on grain volume, 1000-grain weight and grain water content during the grain filling period of wheat. The results showed that grain volume accorded with quadratic equation of one variable, which increased quickly in the first stage of grain filling, then slowly increased to the maximum and then quickly decreased. In both the grain volume in different grain filling period and the maximum grain volume, Xiaoyan 22 was larger than Xiaoyan 503, the sequence of different cultivation models was： Harvest Rain Cultivation （HRC）〉Plastic-film Mulching Cultivation （PMC）〉Conventional Cultivation （CC）, the effect of nitrogen fertilizer on the grain volume wasn＇t significant, the time to maximum volume in different treatments was about 24.3 -- 25. 7 days and the difference wash＇ t significant. Grain weight ehange of different treatments showed a ＂S＂ curve and accorded with logistic growth model; grain weight of Xiaoyan 22 was larger than that of Xiaoyan 503 ; the sequence of grain weight in different cultivation models was： PMC〉 CC 〉 HRC; nitrogen had positive effect on the maximum grain weight of Xiaoyan 22, but negative effect on Xiaoyan 503. In the whole, regards to grain filling rate, Xiaoyan 503 was larger than Xiaoyan 22, CC and HRC were larger than PMC, the nitrogen effect on grain filling rate and grain weight was inverse. The differenee of grain weight in wheat eultivars was related with grain filling process, the difference between Xiaoyan 22 and Xiaoyan 503 wasn＇t significant in the early period, but the difference increased in the middle and late grain filling period, and grain weight of Xiaoyan 22 was significantly larger than that of Xiaoyan 503 in mature. The sequence of grain weight in mature and averagely in the whole gain filling process was： HRC 〉 PMC〉 CC, which was different from the maximum grain weight. W