不同施氮量对临沂地区水稻光合速率、氮肥转化效率及产量的影响

Effects of different nitrogen application rates on photosynthetic rate,nitrogen fertilizer conversion efficiency and yield of rice in Linyi region

采用田间试验研究不同施氮量对临沂市水稻光合速率、氮肥转化效率及产量的影响。结果表明:施氮量为120 kg∕hm^(2)和240 kg∕hm^(2)时,水稻的穗长、结实率、千粒重、单穗粒重显著高于CK处理,且产量以施氮量为240 kg∕hm^(2)时最高,为10 805.1 kg∕hm^(2)。施用氮肥可显著增加水稻籽粒以及秸秆的含氮量,施氮量为120 kg∕hm^(2)和240 kg∕hm^(2)的籽粒含氮量处理间差异不显著。施氮量为120 kg∕hm^(2)时氮素利用率最高,为78.32%,且100 kg籽粒需氮量最高,未施氮肥处理和施氮量360 kg∕hm^(2)处理氮素吸收效率最低。灌浆后期,随着施氮量的增加,水稻旗叶光合速率逐渐上升,胞间二氧化碳浓度逐渐降低,但施氮量高于240 kg∕hm^(2)后光合速率上升不明显。气孔导度和蒸腾速率的变化与光合速率的变化一致。综上,在临沂地区水稻生产上最适宜施氮量为240 kg∕hm^(2)。

In order to study the influence of the nitrogen fertilizer application amount on rice yield,photosynthetic,nitrogen uptake and nitrogen use efficiency characteristics,field experiments were adopted in Linyi region.Results showed that when the nitrogen fertilizer applications were 120 kg∕hm^(2) and 240 kg∕hm^(2),the ear length,seed setting rate,1000-grain weight,and single-grain weight were significantly increased compared with CK treatment,and the highest yield was obtained at 240 kg∕hm^(2) nitrogen application rate,which was 10805.1 kg∕hm^(2).In addition,the application of nitrogen fertilizer could significantly increase the nitrogen content of rice grains and straw.There was no significant difference in grain nitrogen content between 120 kg∕hm^(2) and 240 kg∕hm^(2) nitrogen fertilizer application rates.When the nitrogen fertilizer application was 120 kg∕hm^(2),the nitrogen utilization rate was the highest,which was 78.32%,and the nitrogen requirement of 100 kg grain was the highest.The nitrogen absorption efficiency was the lowest when no nitrogen fertilizer treatment and 360 kg∕hm^(2) treatment were used.With the increase of nitrogen fertilizer application,the photosynthetic rate of flag leaf of rice gradually increased in the late filling stage,but the increase of photosynthetic rate was less obvious after 240 kg∕hm^(2) nitrogen application rate.The intercellular carbon dioxide concentration decreased with the increase of nitrogen application rate.The changes of stomatal conductance and transpiration rate were consistent with those of photosynthetic rate.In summary,the optimum application rate of nitrogen fertilizer was 240 kg∕hm^(2) for rice production in this area.