双稃草对水稻生长和产量性状的影响及其生态经济阈值

Influences of Diplachne fusca(L.)Beauv.on growth and yield traits of rice and its eco-economic threshold

为了解双稃草[Diplachne fusca(L.)Beauv.]对水稻的危害特性,采用杂草-作物竞争试验测定了双稃草敏感种群和抗性种群不同密度对水稻生长发育的影响。结果表明,双稃草对水稻的生长具有显著的抑制作用,水稻茎蘖数随双稃草密度的增加而显著减少,且时间越长影响越大。水稻的穗长、有效穗数、结实率、千粒重及产量均随双稃草密度的增加而降低。用指数函数模型拟合双稃草敏感种群密度与水稻有效穗数的关系较好,用二次曲线模型拟合双稃草抗性种群与水稻有效穗数的关系较好;2个种群与水稻穗长、结实率、千粒重和产量之间的关系均以二次曲线模型拟合较好。双稃草引起的水稻产量损失均以幂函数描述最好,其中敏感种群的为y=2.0917x^(0.6070),抗性种群的为y=2.2387x^(0.5625)。在相同的除草成本时,用10%恶唑酰草胺EC防除双稃草敏感和抗性种群,经济危害允许水平分别为2.24%~2.91%和2.63%~3.42%,敏感种群的生态经济阈值(1.12~1.72株/m^(2))低于抗性种群(1.33~2.13株/m^(2))。

To determine the damage characteristics of sprangletop[Diplachne fusca(L.)Beauv.]on paddy rice,the influence of sprangletop sensitive or resistant populations on the growth and development of rice was measured with weed-crop competition experiment.The results showed that Diplachne fuscahad a significant inhibitory effect on the growth of rice,and the number of tillers decreased with the increase of Diplachne fusca density,and the longer the time,the greater the effect was.The rice spike length,effective spike number,seed rate,1000 grain weight and yield decreased with the increase of Diplachne fusca density.The relationship between sensitive population density and effective spike number was better fitted by exponential function model,and the quadratic curve was better model on resistant population.The quadratic curve model was better described between the two populations and spike length,seed rate,1000 grain weight and yield,respectively.The power function model was better to describe the loss of rice yield caused by Diplachne fusca,in while y=2.0917x^(0.6070)for sensitive population and y=2.2387x^(0.5625)for resistant population.When 10%metamifop emulsifiable concentrate was applied to control sensitive and resistant populations of Diplachne fusca at the same weeding cost in paddy field,the economic infestation levels(EIL)were 2.24%~2.91%and 2.63%~3.42%,respectively.The eco-economic threshold(1.12~1.72 plants/m^(2))of sensitivity was lower than that(1.33~2.13 plants/m^(2))of resistant population.