施氮量对双季稻氮素吸收和产量的影响及其优化

Effect of nitrogen rates on N uptake and use efficiency in double season rice and optimization of nitrogen application

以双季稻鄱优364和K优117为材料,设置6个施氮水平,研究不同施氮量对双季稻产量、经济效益及氮素吸收利用的影响。结果表明:在一定的施氮量范围内,水稻产量先随氮肥施用量的增加而增加,而后有所下降,早稻鄱优364最高产量时的施氮量为184 kg·hm-2,晚稻K优117最高产量时的氮肥施用量为228 kg·hm-2。根据当年水稻价格、投肥成本,拟合出水稻纯增收入与施氮量的一元二次曲线,即早稻为y=-0.219 7x2+75.787x+2 954.7;晚稻为y=-0.167x2+71.07x+5 202.8。由此得出双季早稻经济效益最高时的施氮量为173 kg·hm-2,双季晚稻经济效益最高时的施氮量为213 kg·hm-2。增施氮肥可提高稻谷的吸氮量,但双季稻的氮肥农学利用率均随施氮量的增加而降低,早、晚稻氮肥回收效率随施氮量的增加均呈抛物线状。根据双季稻高产、高效并适当提高氮肥利用率的原则,确定了双季水稻最佳施氮量范围。

In this study, double season rice Poyou 364 and Kyou 117 were used as test materials, the effects of different nitrogen application on double season rice yield, economic efficiency and nitrogen using efficiency were studied. The results showed that rice yield increased with the increase of nitrogen application rates in certain nitrogen range, and then decreased. The yield of early rice Poyou 364 was the highest at nitrogen application rate of 184 kg· hm^-2, and the yield of late rice Kyou 117 was the highest at nitrogen application rate of 228 kg· hm^-2. The equation between economic benefit of rice and N application rate was established based on the output of grain yield and input of fertilizer, as for early rice ： y = - 0. 219 7x2 ＋ 75. 787x ＋ 2 954. 7, and for late rice ： y = - 0. 167x2 ＋ 71.07x ＋ 5 202. 8, According to the equation, the economic benefit of early rice Poyou 364 and late rice Kyou 117 were the highest at nitrogen application rate of 173 kg·hm^-2 , and 213 kg·hm^-2 , respectively. N uptake of grain increased, while N agronomic efficiency decreased, and N recovery efficiency showed a parabola curve with the increase of nitrogen application rates in double season rice. According to the principle of high-yield, high-efficiency and improving nitrogen use efficiency, optimal N application rate was recommended for double season rice.