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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。
In this study, the characteristics of the yield of upland rice 297 under different nitrogen rates were studied in order to find out the reasons for limiting the yield increase after reaching a certain level. The results showed that under the nitrogen application rates of 0, 75 and 150 kg / hm2, the average 2-year yields of Upland rice 297 were 2.8, 3.5 and 3.5 t / hm2, respectively. Among them, the yields of 75 and 150 kg / hm2 N treatments were significantly higher than those of no-nitrogen treatments, while the differences between 75 and 150 kg / hm2 treatments were not significant. Nitrogen addition significantly increased the number of panicles per panicle and the number of spikes per panicle. The difference between 1000-grain weight and harvest index did not show significant difference between nitrogen treatments. However, the seed setting rate decreased after nitrogen application. Especially, the seed setting rate of 150 kg / hm2 treatment was significantly lower than that of non- Nitrogen treatment, at the same time 150kg / hm2 tiller tillering rate lower. The accumulation of dry matter reached the maximum during the middle filling stage, and the dry matter production capacity was low after flowering. Nitrogen fertilizer had no significant effect on the post-anthesis dry matter accumulation. The correlation analysis between the amount of nitrogen uptake and the highest tillering number and spikelet number at the tillering stage showed that suitable accumulation of nitrogen during tillering stage could increase the tillering and increase the number of spikelets per plant at the ear stage. Therefore, under the existing nitrogen application, the yield difference between 75 and 150kg / hm2 treatment was not significant. Compared with 75kg / hm2 treatment, the decrease of spikelet rate and seed set rate of 150kg / hm2 treatment led to the increase of grain yield per unit area The difference was not significant. Meanwhile, the poor anthesis production capacity of anthesis was the reason for the limited yield of upland rice 297 under 150kg / hm2 treatment.