氮是植物体内氨基酸、蛋白质、核酸、辅酶以及光合色素分子等的组成成分，因此，氮的营养状况与许多生理过程密切相关。针对水稻氮肥用量过高这一突出问题，本试验研究了氮肥施用总量对北方粳稻产量及其构成因素、叶面积指数、干物质积累、群体库容量以及品质特征等方面的影响，进一步明确不同氮肥施用量条件下北方粳稻产量和品质形成的调控机制。结果表明，施氮量的增加对叶面积指数、光合势及群体生长率有促进作用，随着施氮量的增加，水稻最高茎数、最高分蘖数、分蘖穗数和分蘖穗比例有逐渐增加的趋势；增加施氮量会导致整精米率、蛋白质含量上升，精米白度、食味值、峰值粘度、最低粘度、崩解值、最终粘度值降低，但不同施氮量对直链淀粉含量影响不大。

Nitrogen is the composition of amino acid, protein, nucleic acids, coenzyme and pigments in photosynthesis, so its nutritional status is closely related to the physical processes. The effects of nitrogen amount on population quality, yield and grain quality of japonica rice in north China were studied in this paper. The results showed that with the increasing of nitrogen application, the leaf area index, photosynthetic potential and population growth rate were promoted; the highest rice stalk number, maximum tiller number, panicle number, proportion of tillers, the head rice rate and protein content were increased gradually; the whiteness, taste value, peak viscosity, low viscosity and final viscosity were decreased. The total amount of nitrogen had little effect on amylose content.