氮肥运筹方式及催芽氮肥用量对再生稻产量及品质的影响

【目的】催芽肥和促苗肥的合理施用是保障再生稻高产优质的重要途径，明确再生稻氮肥运筹方式及催芽氮肥适宜用量，对提高再生稻产量和氮肥利用率、优化再生稻米品质具有重要意义。【方法】本研究采用多年田间试验，以深两优5814为材料，设置5个再生季氮肥(N)处理：不施氮肥(N0-0)；催芽肥60 kg/hm2 (N60-0)、促苗肥60 kg/hm2 (N0-60)、催芽肥和促苗肥各60 kg/hm2 (N60-60)、催芽肥和促苗肥分别为120、60 kg/hm2 (N120-60)。【结果】3年试验产量存在较大差异，但同一年份的再生稻施氮处理均显示了显著的增产效果，N_60-0、N_0-60和N_60-60处理分别较N_0-0平均增产35.8%、40.9%和67.4%。催芽肥和促苗肥配施通过提高有效穗数和每穗粒数进一步提高再生稻产量。随催芽氮肥用量的增加，产量呈先升高后平台的趋势。适宜的催芽氮肥用量和促苗肥配施促进了再生芽的萌发、形成和生长发育，显著增加了倒2节和倒3节(尤其是倒3节)的有效穗数和每穗粒数。养分吸收...

Effects of nitrogen application method and bud-promoting nitrogen fertilizer rate on yield and quality of ratoon rice

  【Objectives】  The rational application of bud-promoting fertilizer and seedling promoting fertilizer is an important way to ensure the optimum yield and quality in rice ratoon season. It is of great significance to clarify the reasonable nitrogen management mode and the rate of germination promoting nitrogen fertilizer in ratoon season to improve the yield and optimize the quality of ratoon rice.   【Methods】  In this study, a multi-year field experiment was conducted with Shenliangyou 5814 cultivar. Five nitrogen fertilizer treatments were set up: no nitrogen fertilizer (N_0-0) in the regenerative season; bud-promoting N 60 kg/hm2 (N_60-0); seedling-promoting N 60 kg/hm2 (N_0-60); bud- and seedling-promoting N 60 kg/hm2 each (N_60-60); bud-promoting N 120 kg/hm2 and seedling-promoting N 60 kg/hm2 (N_120-60). The nitrogen fertilizer was applied in the regenerative season. The growth, yield and yield components of ratoon rice were investigated.  【Results】  Although there were large variations in the yields of the three-year trials, the nitrogen application treatments in the same year could significantly improve the yield of ratoon rice. Compared with N_0-0 treatment, N_60-0, N_0-60, and N_60-60 treatments increased production by 35.8%, 40.9%, and 67.4%, respectively. The combined application of bud-promoting fertilizer and seedling- promoting fertilizer further increased the yield of ratoon rice by increasing the number of effective panicles and grains per panicle. With the increase of nitrogen fertilizer application rate, the yield increased firstly and then became stable. The suitable combination of bud-promoting fertilizer and seedling-promoting fertilizer promoted the germination, formation, growth, and development of regenerated buds, and significantly increased the number of effective panicles and grains per panicle at 2nd and 3rd nodes (especially 3rd nodes). Further, with increasing nitrogen application rate, nitrogen uptake in shoot of ratoon rice increased significantly. Compared with N_0-0 treatment, N_60-0, N_0-60, N_60-60 and N_120-60 treatments increased nitrogen uptake by 51.31%, 57.70%, 91.33%, and 124.53% on average, respectively, but the NUE exhibited a decreasing trend. In terms of quality, increasing rate of the nitrogen fertilizer led to an initial increase in the processing quality, appearance quality, and amylose content of ratoon rice but they later decreased, while the protein content increased gradually. Compared with other treatments, the processing quality and appearance quality of ratoon rice were optimized when the combination of bud-promoting fertilizer and seedling-promoting fertilizer was applied at N_60-60. Compared with N_0-0 treatment, brown rice rate, milled rice rate and head milled rice rate of N_60-60 treatment were increased by 2.7%, 1.3%, and 6.7%, respectively. Chalkiness and chalkiness grain rate decreased by 13.8% and 22.6%, respectively. However, when bud-promoting fertilizer application rate increased further (N_120-60), the processing quality and appearance quality of rice were reduced, with the head milled rice rate decreasing and chalkiness grain rate increasing most significantly.   【Conclusions】  Under this experimental conditions, the application of N 60 kg/hm2 bud-promoting fertilizer and 60 kg/hm2 seedling-promoting fertilizer significantly improves the yield, nitrogen use efficiency, and rice quality.