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期 刊 ：植物保护学报 2008年

关键词：空心莲子草；水稻；经济危害允许水平；经济阈值；

Keywords:Alternanthera philoxeroides, paddy rice, economic infestation level, economic threshold,

摘 要 ：采用添加系列试验和模型拟合的方法研究不同空心莲子草密度下水稻生长性状的变化规律。结果表明,水稻在空心莲子草的竞争干扰下,穗长、有效穗数、千粒重及产量均随其密度的增加而逐渐降低。指数模型拟合空心莲子草与水稻穗长(y=18.145e^-0.003x,P<0.001)的关系较好,二次曲线拟合其与水稻有效穗数(y=0.001x²-0.105x+11.683,P<0.001)的关系较好,而拟合其与水稻千粒重(y=-0.154lnx+20.261,P<0.001)、产量(y=-582.764lnx+6282.120, P<0.001)及产量损失(y=9.435lnx-1.689, P<0.001)间的关系均以对数模型为佳。稻田使用20%氯氟吡氧乙酸乳油进行化学除草时,空心莲子草的经济危害允许水平为1.40%,经济阈值为1.39株/m²。

Abstract:Additive series experiment and curve fits were adopted to study the change of rice yield characters under different densities of Alternanthera philoxeroides. The results showed that with the interference of Alternanthera philoxeroides, the spike length, spike number, 1000-grain weight and grain yield of paddy rice decreased gradually as the weed density increased. The exponential regression model was relatively better for fitting the relationship between Alternanthera philoxeroides density and rice spike length (y=18.145e^-0.003x, P<0.001). For spike number, quadratic model (y=0.001x²-0.105x+11.683, P<0.001) is better. But logarithmic model was the best for 1000-grain weight (y=-0.154lnx+20.261, P<0.001), rice yield (y=-582.764lnx+6282.120, P<0.001) and yield loss (y=9.435lnx-1.689, P<0.001). When herbicide fluroxypyr-methyl 20% EC was used to control Alternanthera philoxeroides in paddy fields, the economic infestation level for Alternanthera philoxeroides was 1.40% and the economic threshold was 1.39 plant/m².

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