不同施氮量对旱稻297产量构成因子影响的研究(Ⅰ)——产量构成、干物质生产与氮素吸收

Effect of nitrogen on yield components of aerobic rice,HD297(Ⅰ):Yield components,dry matter production and N uptake

本试验研究了不同施氮量下旱稻297产量形成的特点,以期探明施氮量达到一定水平后,限制产量进一步提高的原因。结果表明:旱稻297在0、75和150kg/hm2的施氮量下,2年平均产量分别是2.8、3.5和3.5t/hm2。其中,75和150kg/hm2施氮处理产量显著高于不施氮处理,75和150kg/hm2处理间差异不显著。施氮可以显著提高有效穗数和穗粒数,千粒重和收获指数在氮素处理间差异不显著,但是施氮后结实率呈降低趋势,尤其是150kg/hm2处理的结实率显著低于不施氮处理,同时150kg/hm2处理的分蘖成穗率较低。干物质积累在灌浆中期达到最大,开花后干物质生产能力较低,施氮对花后干物质累积没有显著影响。分蘖盛期的吸氮量与最高分蘖数和穗粒数的相关分析表明,分蘖盛期适宜的氮累积能够促进分蘖的增加和穗形成时期单株穗粒数的增加。因此,在现有的施氮措施下,75和150kg/hm2处理间产量差异不显著;与75kg/hm2处理相比,150kg/hm2处理的分蘖成穗率和结实率降低导致单位面积的实粒数差异不显著,同时,花后干物质生产能力较差是限制旱稻297在150kg/hm2处理下产量提高的原因。

A two-year field experiment was conducted to study the effect of nitrogen on grain yield and yield components of aerobic rice,HD297.The objective was to clarify the constraints for improving grain yield when amount of applied nitrogen reached a certain level.The grain yield was 2.8,3.5 and 3.5 t/hm2 respectively over two years under 0,75 and 150 kg/hm2（N） treatments.Compared with 0 kg/hm2（N）,N input increased the grain yield significantly,but there was no difference between 75 and 150 kg/hm2（N）.With N input,the productive tillers and grains per panicle increased significantly and there was no difference of thousand grain weight and harvest index among the nitrogen treatments,while the percentage of filled grains decreased and the ratio of non-productive tillers increased especially under N150 treatment.The dry matter accumulation reached maximum at the middle stage of grain filling followed by a poor dry matter production after anthesis.Moreover,nitrogen input had little effect on the dry matter production after anthesis.The N uptake at maximum tiller stage could improve tiller numbers and promote spikelet formation at panicle initiation.Therefore,there was no difference of the grain yield between N75 and N150 treatment;compared with N75 treatment,the lower ratio of productive tiller,lower percentage of filled grains and poor dry matter production after anthesis were three major factors for improving the grain yield of HD 297 under 150 kg/hm2（N） treatment.