施氮量对优质超级稻产量、品质及氮素利用的影响OA

In order to determine the suitable nitrogen application rate of the high-quality super rice variety Huazheyou 261,a field experiment was carried out with the single-factor randomized block design.Five nitrogen application rates were set:N0(no nitrogen application),N135(135 kg/hm2 pure nitrogen application),N180(180 kg/hm2 pure nitrogen application),N225(225 kg/hm2 pure nitrogen application),and N270(270 kg/hm2 pure nitrogen application).Effects of different nitrogen application rates on the number of tillers,yield,yield components,grain quality,dry matter accumulation,and nitrogen utilization efficiency of Huazheyou 261 were studied.The results were as follows.(1)The number of peak seedlings increased with the increase in the nitrogen application rate,and the peak time appeared earlier under higher nitrogen application rate.(2)With the increase in the nitrogen application rate,the yield first increased and then decreased,being the highest under the N225 treatment.The two-year average yield under this treatment significantly increased by 55.1％,11.5％,4.1％,and 9.9％,respectively,compared with those under N0,N135,N180,and N270 treatments.The number of effective panicles,total number of grains per panicle,and total number of spikelets showed consistent variation trends with the yield,while the seed setting rate and 1 000-grain weight showed a downward trend.(3)With the increase in the nitrogen application rate,the brown rice rate,milled rice rate,and head rice rate in the two years first increased and then decreased.The brown rice rate in 2022 and the brown rice rate,milled rice rate,and head rice rate in 2023 were the highest under the N225 treatment and had no significant differences with those under N180 treatment.The chalkiness degree and amylose content decreased gradually.The alkali spreading value gradually increased in 2022 and showed a trend of first increasing and then decreasing in 2023.The protein content increased gradually.(4)With the increase in the nitrogen application rate,the dry matter accumulation at different stages increased(except the full heading-maturity stage in 2022),while the dry matter transport,apparent output rate,and harvest index first increased and then decreased.The dry matter transport,apparent output rate,and apparent conversion rate reached the maximum values under the N180 treatment(except 2023),and the harvest index reached its maximum value under the N225 treatment.At the maturity stage,the total nitrogen accumulation in stem sheaths,leaves,and whole plants increased,and that in panicles first increased and then decreased.The nitrogen distribution rate showed a decreasing trend in panicles and an increasing trend in stem sheaths and leaves.The nitrogen fertilizer agronomic utilization rate,nitrogen fertilizer physiological utilization rate,nitrogen fertilizer partial factor productivity,soil nitrogen dependence rate,yield utilization efficiency of nitrogen fertilizer,and nitrogen harvest index decreased with the increase in the nitrogen application rate.The absorption and utilization rate of nitrogen fertilizer and the contribution rate of nitrogen fertilizer first increased and then decreased,being the highest under the N225 treatment(except the absorption and utilization rate of nitrogen fertilizer in 2023).In summary,under conditions of this experiment,the comprehensive performance of N225 treatment was the best.The regression analysis of the yield and nitrogen application rate showed that the optimum nitrogen application rate for Huazheyou 261 in the study area was 174.0～206.0 kg/hm2,which could achieve the synergistic optimization of the yield,grain quality,and nitrogen utilization.