【摘要】 采用田间试验研究了稻草还田环境下施N模式对稻田生态系统N素吸收量及N肥利用率的影响。结果表明:稻草还田配施N肥能显著提高水稻N素吸收转化功能,且高量常规N处理下尽管水稻N素吸收量增多,但只有一定量N素能转移到穗部,其余则仍然留存在营养器官中。所有处理N肥的吸收利用率为26.7%~30.7%、农学利用率为10.5~12.2 kg.kg-1,N肥利用率较低,且随着施N量增加呈下降趋势。随着与稻草配合施用,N肥利用率各指标中除吸收利用率略有下降外,其他各指标(包括农学利用率、生理利用率和偏生产力)均有一定程度提高。根据稻田作物N素吸收转化状况与N肥利用率,在全年稻草还田量为7 500 kg.hm-2的红壤稻田系统,建议全年适宜配施N量为185 kg.hm-2。更多还原

【Abstract】 Field studies were conducted to investigate effects of rice straw incorporation and nitrogen application models on process of nitrogen uptake by rice paddy ecosystem and fertilizer-N use efficiency in the double rice cropping system.Results show that rice straw incorporation coupled with N application at a proper rate could increase nitrogen uptake by rice plants and nitrogen cycling in the rice field ecosystem.In the treatment high in N application rate,nitrogen uptake by rice increased,but the amount of N transferred to the ears was limited and the rest still remained in the vegetative organs.N recovery rate,regardless of treatment,ranged between 26.7% and 30.7%,and N agronomic efficiency,between 10.5 and 12.2 kg·kg^-1.Obviously,fertilizer-N use efficiency is low,and it decreased with rising nitrogen application rate.Straw incorporation improved slightly use efficiency of applied N,including N agronomic efficiency,N physiological efficiency,and partial productivity,except for N recovery rate.According to the nitrogen absorption and transformation,the nitrogenous fertilizer use efficiency,and the fact that 7 500 kg·hm^-2 rice straw is incorporated annually,it is recommended that 185 kg·hm^-2 of N be applied a year in the red earth-paddy system.更多还原