长沙烟区烟后晚稻适宜氮肥施用量与运筹方式研究

为给长沙烟区烟后晚稻高产高效栽培提供科学依据,以超级杂交稻品种深优9586为材料,于2011~2012年在长沙市宁乡烟区研究了施氮量与氮肥运筹方式对烟后晚稻产量形成与氮素吸收利用的影响。结果表明:(1)在施氮0~120 kg/hm~2范围内,晚稻产量随施氮量增加呈先增后降趋势,施氮90 kg/hm~2条件下产量最高,过量施氮导致减产的原因在于有效穗数与千粒重下降;(2)氮肥运筹方式影响晚稻产量,施氮90 kg/hm~2时W3处理(基蘖肥∶穗肥∶粒肥比例为0.5∶0.25∶0.25)产量最高,施氮30~60 kg/hm~2时以W4处理(0.25∶0.5∶0.25)产量最高,增产的原因在于氮肥后移提高了烟后晚稻齐穗期叶面积指数、灌浆中期叶面积指数和SPAD值;(3)氮肥用量增大,烟后晚稻氮积累量提高,但氮农学利用率、氮肥吸收利用率、氮生理利用率、氮素干物质生产效率、氮素稻谷生产效率下降;氮肥运筹方式影响氮素利用效率,施氮量较低时,氮肥后移有利于氮素利用效率的提高,而施氮量偏高时(90 kg/hm~2)后期施用氮肥比例不宜过高。可见,为提高长沙烟区烟后晚稻产量和氮素利用效率,施氮量在60 kg/hm~2以内可采取氮肥后移策略,而施氮90 kg/hm~2时后期施氮比例不宜过高。

Study on optimal nitrogen application rate and planning mode for late rice after tobacco in Changsha tobacco planting area

To provide the scientific basis for high-yielding and efficient cultivation of late rice after tobacco in Changsha tobacco planting area, effects of nitrogen application rate and nitrogen planning mode on yield formation and nitrogen absorption and uti-lization of late rice after tobacco were studied with super hybrid rice variety “Shenyou 9586” as material in Ningxiang tobacco planting area in 2011~2012. The results showed that (1) the yield of late rice after tobacco showed the increase-decrease trend with the increment of nitrogen rate in 0~ 120 kg/hm2 , and the highest yield was gained under N 90 kg/hm2 . Excessive nitrogen fertilizer deduced yield decrease because of the decrease of effective panicles and 1000-grain weight. (2) The yield of late rice was affected by nitrogen planning mode. The best nitrogen planning mode under N 90 kg/hm2 condition was W3 ( till-ering N fertilizer∶booting N fertilizer∶grain N fertilizer=0. 5∶0. 25∶0. 25 ) , and yield of W4 ( 0. 25∶0. 5∶0. 25 ) was highest under N 30 ~60 kg/hm2 conditions, and the reason of yield-increasing lied in LAI at full heading stage and middle filling stage, and higher chlorophyll content in middle filling stage were improved by postponing nitrogen. (3) With the increment of nitrogen rate, N accumulation was increased, while NAE, NRE, NPE, NDMPE, NGPE of late rice after tobacco was de-creased. Nitrogen utilization efficiency was also affected by nitrogen planning mode, postponing nitrogen could improve nitro-gen utilization efficiency when nitrogen application rate was lower, while the nitrogen ratio at late growth stage should not be too higher under N 90 kg/hm2 condition. So, to improve yield and nitrogen utilization efficiency, postponing nitrogen strategy can be adopted when N rate is below to N 60 kg /hm2 , while the proportion of N application at late stage of rice should not be too higher when N rate is N 90 kg /hm2 .