减钾对华南早晚兼用型水稻源库特性的影响

Effects of reduced potassium fertilizer on source-sink characteristics of early/late season rice in South China

【目的】分析低氮磷水平下减钾对不同早晚兼用型水稻品种源库特性的影响,为水稻精确减量化施肥及营养物质的高效利用提供参考。【方法】在大田低氮低磷条件下,设置3个钾肥处理(常规施钾(K2O 135.0kg/hm2)、减钾处理(较常规施钾减22%,K2O 105.3kg/hm2)和不施钾肥),探讨不同钾肥处理对不同基因型水稻("粤晶丝苗2号"、"桂香占"、"华优8305"和"天优998")品种源库特性的影响。【结果】与常规施钾相比,减钾处理有利于"华优8305"和"天优998"增产,产量分别提高7.44%和19.39%;减钾处理降低了"桂香占"产量,但与常规施钾处理差异不显著。与常规施钾相比,减钾处理有利于提高"粤晶丝苗2号"库容,但降低了库容有效充实度、部分叶源(后期叶面积指数、前期叶绿素含量和叶片老化指数),最终导致产量显著下降了14.67%。【结论】在低氮低磷条件下,适度减钾通过维持源库协调可以使水稻增产或稳产。

【Objective】Effects of reduced potassium （K） on sourcesink characteristics of different early/late season rice （Oryza sativa L.） varieties with low nitrogen （N） and phosphate （P） fertilizer level were analyzed to improve precise fertilization decrese and efficient utilization of nutrients. 【Method】Three K rates, conventional K （K2O 135.0 kg/hm2）,reduced K by 22% （K2O 105.3 kg/hm2） and without K,were conducted in field experiment with low level of N and P fertilizers.The effects of different K treatments on sourcesink characteristics of rice varieties （“Yuejingsimiao 2”,“Guixiangzhan”,“Huayou 8305” and “Tianyou 998”） were explorded.【Result】Compared with conventional K,treatment with reduced K benefited “Huayou 8305” and “Tianyou 998” in obtaining higher yield,and their yields increased by 7.44% and 19.39%,respectively.Treatment with reduced K reduced yield of “Guixiangzhan”,but the decrease was not significant compared to conventional K.Treatment with reduced K improved sink capacity of “Yuejingsimiao 2”,but reduced available plumpness of sink and leaf source （leaf area index in late growth stage,chlorophyll content and leaf senescence index in early growth stage）,and ultimately led to a 14.67% reduction of yield.【Conclusion】Under lower N and P level,a proper reduction of K with coordination of sourcesink could obtain higher yield or maintain stable yield.