不同叶龄蘖、穗氮肥组合对粳稻产量及氮素利用的影响

Effects of precision leaf age fertilization on yield and nitrogen utilization of japonica rice

以主茎叶片数不同的粳稻品种吉粳88 (14片)、沈农265 (15片)和沈农1401 (16片)为试材,采用大田筒栽方式,在总施氮量225kghm^–2及轻简施肥(基肥、蘖肥、穗肥)模式基础上,设置基蘖肥∶穗肥6∶4和8∶2两种施肥比例,并分设不同源、库叶龄期施氮组合即不同叶龄蘖、穗肥精确施氮组合。分析了不同源库期氮肥运筹模式对水稻农艺性状、产量及氮素利用特性的影响。结果表明:(1)在有效穗数、分化颖花数、产量和氮素利用率方面,吉粳88、沈农265、沈农1401不同氮肥运筹下最佳蘖、穗肥叶龄组合均为6∶4显著高于8∶2。(2)不同氮肥运筹下,吉粳88在8叶(叶龄指数57.1%)、沈农265在9叶(叶龄指数60.0%)、沈农1401在10叶(叶龄指数62.5%)时,即叶龄指数在60%左右时,施用蘖肥效果最佳,最终穗数最多,对保蘖起主要作用;吉粳88在11叶(叶龄指数78.6%)、沈农265在12叶(叶龄指数80.0%)、沈农1401在13叶(叶龄指数81.3%)时,即叶龄指数在80%左右时,施用穗肥效果最佳,最终穗粒数最多,对促花起主要作用。(3)吉粳88-6∶4 (8, 11),沈农265-6∶4 (9, 12),沈农1401-6∶4 (10, 13) 3组处理,在产量、氮素积累量、氮素吸收利用率、农学利用率及偏生产力等方面,显著高于同品种不同叶龄蘖、穗氮肥组合中的其他处理。因此,适当延迟蘖肥施用叶龄期(叶龄指数60%左右)、提前穗肥施用叶龄期(叶龄指数80%左右)同时增加穗肥施用比例,既可以显著提高氮素积累量、氮素吸收利用率、农学利用率及偏生产力,又能显著促进成穗率的提高和颖花数的分化,达到保蘖促花的双重作用,实现优源、扩库、充实的目标,从而获得高产。

The japonica rice cultivar Jigeng 88(14 leaves), Shennong 265(15 leaves) and Shennong 1401(16 leaves) with different main leaf ages were used to analyze the effects of different source-sink nitrogen fertilizer application models on agronomic traits, yield and nitrogen utilization characteristics of rice grown in the field-tube condition. Two kinds of fertilizer proportions(base fertilizer: panicle fertilizer was 6:4 and 8:2) were set under 225 kg hm–2 of nitrogen application based on the light and simple fertilization model(basal fertilizer, tillering fertilizer, panicle fertilizer). The tillering fertilizer was applied at the stage of source construction, and panicle fertilizer was applied at stage of sink formation. The precise nitrogen application combined different nitrogen fertilizer modes for tillering and panicle fertilizers with different leaf ages. Number of differentiated spikelets, effective panicles, yield, and nitrogen use efficiency, were significantly higher by using the 6:4 fertilizer proportions than by using 8:2 under all nitrogen fertilizer application models in these cultivars. Under different nitrogen fertilizer regimes, the 8 leaves of Jigeng 88(leaf age index was 57.1%), 9 leaves of Shennong 265(leaf age index was 60.0%), and 10 leaves of Shennong 1401(leaf age index was 62.55%) were the best stage to apply tillering fertilizer. It means that the leaf age index about 60% is better to protect the more panicle formation. The 11 leaves of Jigeng 88(leaf age index was 78.6%), 12 leaves of Shennong 265(leaf age index was 80.0%), 13 leaves of Shennong 1401(leaf age index was 81.3%) were the best stage to apply panicle fertilizer. It means that leaf age index about 80% is better to promote spikelet differentiation. The yield, nitrogen accumulation, nitrogen uptake and utilization, agronomic efficiency, and partial productivity were significantly higher in 6:4(8, 11) of Jigeng 88, 6:4(9, 12) of Shennong 265, 6:4(10, 13) of Shennong 1401 than in other treatments. Therefore, the delayed leaf age of tillering nitrogen fertilizer application(leaf age index was about 60%), ahead of applied the panicle fertilizer(leaf age index was about 80%), and increasing the ratio of nitrogen fertilizer application not only significantly increase nitrogen accumulation, nitrogen absorption and utilization, nitrogen agronomic utilization rate and partial productivity but also promote number of differentiated spikelets and the percentage of effective panicle number, achieving the dual role of protecting and promoting spikelets, and high yields.