湖北省两个生态区水稻施钾效果及农田钾素平衡研究

在湖北省江汉平原和鄂东南丘陵两个典型的生态区布置田间试验，研究K肥施用对水稻产量、经济效益及K素平衡的影响。结果表明，江汉平原生态区水稻产量有随施K量增加而逐渐升高的趋势，与不施K肥处理相比，施K（K2O）187.5 kg/hm2 时增产量最高为3 007 kg/hm2，纯增经济效益4 136 元/hm2；鄂东南丘陵生态区施K效果显著，但各施K水平的差异不大，施K 150 kg/hm2 时水稻的增产量及纯增经济效益最高，分别为1 495 kg/hm2和1 852 元/hm2。江汉平原生态区各施K处理的K肥平均表观利用率为74.6%，低于鄂东南丘陵生态区的98.7%。研究结果还显示，两个生态区的农田K素在种植水稻后均呈负平衡，K肥施用可以缓解土壤K素的亏缺。

Study on effects of potassium (K) fertilizer on rice and K balance of paddy fields in different types of ecoregions of Hubei Province

Two field experiments of rice were conducted to study the effects of potassium (K) fertilizer on rice yield, economic profit, K utilization rate and on the field K balance in hilly ecoregion of southeastern Hubei and Jianghan Plain ecoregion. The results showed that K fertilizer increased obviously rice yield and economic profits in the two ecoregions, rice yield in Jianghan Plain increased with the increase of K utilization rate and the highest increased yield was 3 007 kg/hm2 with net economic profit of 4 136 Yuan/ hm2 under 187.5 kg/hm2 application of K2O. Rice yield in southeastern Hubei increased significantly with K fertilization but no significant differences among different rates of K fertilization, 150 kg/hm2 application of K2O obtained the highest increased rice yield (1 495 kg/hm2) with net economic profit (1 852Yuan/ hm2). The average K utilization rate in Jianghan Plain was 74.6%, which was lower than that (98.7%) in hilly ecoregion of southeastern Hubei. The result also found the negative K balances in the two ecoregions after rice growing, which could be relieved by K fertilizer application.