增苗节氮对晚稻生物学特性及产量的影响

匡炜 方宝华 李超 刘洋 朱国奇 戴力 张玉烛

摘 要：针对目前湖南部分地区水稻生产中氮肥施用过量的问题，以湘晚籼12号为试验材料，设置以施氮量为主区、抛栽密度为副区的裂区试验，分析两因素及其互作对晚稻生产的影响。结果表明：施氮量与抛栽密度的交互作用不显著，但对水稻产量有较大影响;在施氮量9 kg/667m2、抛栽密度2.6万株/667m2模式下，晚稻理论产量最高，为572.29 kg/667m2;通过二次多项式回归分析施氮量、抛栽密度密度与产量间的关系可知，产量最高为562.26 kg/667m2时，对应的施氮量为10.33 kg/667m2、抛栽密度为2.6万株/667m2，比常规施氮量节省13.92%。这说明合理减少氮肥用量、提高抛秧密度可实现水稻稳产、氮肥高效利用。

关键词：增苗节氮;互作效应;晚稻;生物学特性;产量

中图分类号：S511.33文献标识码：A文章编号：1006-060X（2020）03-0014-03

Abstract： In order to solve the problem of excessive nitrogen application in rice production in some areas of Hunan Province， a split-plot design was conducted by using the late rice cultivar Xiangwanyan No. 12 as the test material， nitrogen application level as the main factor， and planting density as the secondary factor， influences of two factors and their interactions on late rice production were analyzed. The results show that nitrogen application level and transplanting density have great influence on rice yield， but the interaction between nitrogen application level and transplanting density is not obvious. Under the nitrogen application rate of 135 kg/hm2 and the planting density of 390 000 plants/hm2， the highest theoretical yield was 8 584.35 kg/hm2. Through the quadratic polynomial regression analysis of the relationship between nitrogen  application rate， planting density and grain yield， it indicated that when the highest yield was 8 433.9 kg/hm2， the corresponding planting density was 390 000 plants/hm2 and nitrogen application rate was 154.95 kg/hm2， 13.92% less than the conventional nitrogen consumption. The above results show that reasonablely reducing nitrogen consumption and increasing planting density can not only achieve stable rice yield but also increase the nitrogen utilization rate.

Key words： reducing nitrogen consumption and increasing planting density; interaction effect; late rice; biological characteristics; yield

氮肥損失严重是我国水稻种植过程中的一大问题，既带来经济损失又造成环境污染。我国集约化种植区氮肥施用过量的现象相当普遍，如果这种粗放施肥方式得不到实质性改善，那么施氮过量造成的环境污染问题将越来越严重[1-5]。种植密度也是影响水稻生产的一个重要因素，前人通过研究发现密度对水稻的养分吸收、品质、产量等都有影响[3-8]。目前，关于肥料和密度对水稻产量及氮肥利用率的协作效应已有相关报道[9-13]，但关于增苗节氮措施对湖南地区抛栽晚稻影响的报道较少见。研究以常规稻为材料，通过增苗节氮的栽培措施，在稳产的前提下实现节氮的目标，以期为湖南地区晚稻减氮栽培提供依据。……