Abstract: Field fertilizer experiments were conducted to study K uptake, distribution and use efficiency of hybrid and conventional rice un der different low-K stress conditions. Results indicated that grain yield and t otal K uptake by rice increased, while K use efficiency of rice decreased signi ficantly, and interaction effect between cropping history and K application was also significant. The phase from panicle initiation to flowering was critical for K uptake by rice and more than half of the total plant K was accumulated du ring this phase. Total K uptake by hybrid rice Xieyou 46 was significantly highe r compared with conventional rice Xiushui 11 from high-K soil. However, the K use efficiency of Xieyou 46 was significantly lower compared with Xiushui 11 , indicating that hybrid rice possessed potassium luxury consumption character. Under K deficiency situation, K uptake by hybrid rice was less than that by co nventional rice, there was no significant difference between the two rice variet ies in K use efficiency. Resin capsule method was used to measure the dynamic s of soil bio-available K during rice growth period. It was found that the accu mulated K of rice was positively correlated with the adsorbed K of resin capsule s embedded in situ soil for 7 days.

Key words: rice, potassium, nutrient use efficiency, uptake

摘要： 通过田间试验，研究了在不同程度低钾胁迫条件下，杂交稻和常规稻在不同生育阶段对钾的吸收、分配和利用效率。在连续8季施氮、磷肥而不施钾肥的严重低钾胁迫条件下，施用钾肥使稻谷产量、水稻钾吸收总量显著增加而钾利用效率显著降低，同时表现出明显的耕作历史同施用钾肥间的交互作用。从幼穗分化期到抽穗期，水稻钾的积累量约占总积累量的一半以上，为水稻积累钾的关键时期。水稻对钾肥反应存在明显的品种间差异，在供钾充足条件下，杂交稻协优46的钾吸收量显著大于常规稻秀水11，但其钾利用效率却显著低于秀水11，表现出对钾的奢侈性吸收；在缺K条件下，杂交稻的钾吸收量低于常规稻，其钾利用效率与常规稻无明显差异。运用混合型离子交换树脂球测试法，可以了解淹水条件下土壤中生物有效性钾的动态变化特征，原地埋置7 d的树脂球的钾吸附量同水稻地上部分钾吸收量呈显著正相关。

关键词: 水稻, 钾, 养分利用效率, 吸收