氮肥利用对水稻不同生育期的影响概述

Effects of Nitrogen Utilization on Different Growth Stages of Rice

明确水稻生育期氮肥利用与产量的关系,对水稻高产和合理施肥措施的制定具有重要意义。在相同落谷量、等氮量条件下,氮肥基施比例过多,不利于水稻萌芽而影响成苗率。茎蘖增长速度与最高分蘖数随基施氮肥比例增加而提高,但基肥施氮量大易造成水稻群体过大而使成穗率降低。前期基蘖肥高时,可促进水稻的地上部分生长以及物质运输,更有利于中稻分蘖,但也会抑制地下部分的生长。降低基施氮肥比例可促进根系生长,增加穗肥比例,可增加地上部分干物质量,保持后期根系活力,并提高产量和抗倒伏能力。在水稻不同生育期,适宜的施氮量利于水稻群体的高效生长,形成较高的成穗率、单穗粒数和千粒质量,提高水稻产量。

A clear understanding of the relationship between nitrogen utilization at rice growth stages and its yield is of great significance for establishing effective fertilization strategies and attaining a high yield. With a fixed rice seeding rate and nitrogen fertilization rate, an overly high proportion of nitrogen fertilization at the basal stage is not conducive to rice germination, thereby reducing the survival rate of seedlings. Elevating the basal nitrogen rate leads to increases in the rate of stem and tiller growth and the maximum of tiller number, but a reduction in the rate of spikelet formation caused by a large rice population. High proportions of N-fertilization at basal and tillering stages can promote the growth of above-ground parts of rice plants and material transport, being especially conducive to rice tillering, but can inhibit the growth of the under-ground parts. By contrast, a low proportion of basal nitrogen rate can promote root growth; increasing the proportion of N-fertilization at the panicle stage can improve the dry weight of the above-ground parts and the vigor of the roots, leading to a higher yield and stronger anti-lodging ability. All in all, appropriate N-fertilization rates at different growth stages of rice can stimulate the efficient growth of rice population; and increase the rate of spikelet formation, grain number per panicle, and 1000 grain weight, therefore elevating rice yield.