钾对不同类型水稻氮素吸收利用的影响

以常规粳稻武运粳7号、武香粳14和杂交粳稻86优8号、泗优422为材料，研究了钾对水稻氮素吸收、分配和利用的影响。结果表明，钾对水稻有明显增产效应，增产率4.56%~14.77%；钾提高了水稻不同生育阶段植株吸氮量，以拔节期到抽穗期氮素积累增量最大，但吸氮比例下降；钾促进了抽穗后氮素转运量和转运率，提高了氮素在不同器官分配量及叶片、穗分配比例，但降低了茎鞘分配比例；钾增强了植株对肥料氮吸收，基肥氮素利用率、全生育期氮素利用率和氮素收获指数显著增长，但降低了植株氮生产效率；以180 kg hm^-2K₂O处理产量最高，氮素积累量、转运量和转运率以及不同器官分配量最大，基肥氮素利用效率、植株对肥料氮吸收量和全生育期氮素利用率最大，但拔节期到抽穗期氮素吸收比例、茎鞘氮素分配比例和植株氮生产效率最低；常规粳稻产量高于杂交粳稻，其氮素利用率相对较大。

Effect of Potassium Application Rates on Nitrogen Absorption and Utilization of Different Types of Rice

Potassium, nitrogen and their interaction play important roles in plant growth, development and yield of rice. Appropriate potassium can stimulate nitrogen accumulation and translocation in rice. In order to identify plant nitrogen absorption, distribution and utilization characteristics of rice under potassium supply, a field experiment was conducted with four potassium rates (0, 90, 180, 270 kg ha^-1K₂O) using conventional japonica cultivars (Wuyunjing 7 and Wuxiangjing 14) and hybrid japonica cultivars (86 you 8, Siyou 422) from 2004 to 2005 on Experimental Farm of Nanjing Agricultural University, Jiangsu province, China. Potassium application increased rice yield (4.56-14.77%) and nitrogen accumulation during growth stages, with the maximum from elongation stage to heading stage, but nitrogen uptake ratio decreased. Potassium application enhanced nitrogen transport amount and percentage after anthesis, as well as nitrogen accumulation in different rice organs, nitrogen distribution percentage in leaves and panicles, whereas declined nitrogen distribution percentage in culm and sheath. Nitrogen absorption from fertilizer, basic nitrogen recovery efficiency before elongation stage, nitrogen recovery efficiency during the whole growing stage, and nitrogen harvest index were raised significantly, but plant nitrogen productivity was opposite. Grain yield, nitrogen accumulation, nitrogen translocation amount and percentage after anthesis, and nitrogen distribution in different rice organs amounted to the maximum at K₂O application rate of 180 kg ha^-1, as well as nitrogen absorption from fertilizer, basic nitrogen recovery efficiency before elongation stage, nitrogen recovery efficiency during the whole growing stage. However, nitrogen absorption percentage from elongation stage to heading stage, nitrogen distribution percentage in culm and sheath, plant nitrogen productivity decreased to the minimum. The yield and nitrogen recovery efficiency of conventional japonica cultivars were higher than those of hybrid japonica cultivars.