龙葵对棉花生长的影响及其经济阈值分析

【目的】研究棉田龙葵对棉花生长和产量性状的影响及其防治经济阈值,为制定棉田龙葵的防治指标和措施提供科学依据。【方法】在大田条件下,研究不同密度（0、1、4、7、10、15株/m²）龙葵持续危害对棉花农艺性状和产量性状的影响,采取模型拟合法分析不同密度龙葵与棉花产量损失率间的函数关系,并根据经济危害允许水平分析龙葵的防治经济阈值。【结果】棉花的株高、茎粗、主茎节数随龙葵密度的增加而降低,龙葵对棉花中部铃铃数和产量具有显著影响（P<0.05）。当龙葵密度为1株/m²时,棉花产量损失率为60.92%;当龙葵密度达到15株/m²时,棉花产量损失率为100%。对数模型y =12.594 ln（X） + 58.025能较好地拟合龙葵密度与棉花产量损失率间的关系,根据经济危害允许水平和对数模型,人工防除龙葵的经济阈值为0.016 株/m²,96%精异丙甲草胺EC化学防除的经济阈值为0.017 株/m²。【结论】龙葵对棉花的抑制效应与其密度呈正相关,当田间龙葵持续危害密度高于0.016 株/m²时,即160 株/hm²,应及时防除。

Study on the Influence of Solanum nigrum L. on Cotton Growth and Its Economic Threshold

【Objective】 Solanum nigrum L. is a troublesome weed seriously damaging cotton growth development. The objective of this study is to investigate the effects of Solanum nigrum L. on cotton growth in cotton fields and yield traits and its economic threshold, and provide a scientific basis for the formulation of control parameters on Solanum nigrum L. in cotton fields and its control measures. 【Method】 The effects of different densities of Solanum nigrum L.（0, 1, 4, 7, 10, 15 plants/m²） on cotton agronomic traits and yield traits were investigated in field conditions. Then the functional relationship between different densities of Solanum nigrum L. and cotton yields loss rate was researched by using model fitting method. Control economic thresholds on Solanum nigrum L. in cotton were derived on the basis of the economic infestation level formula. 【Result】 The plant height, stem thick and the number of main stem nodes of cotton decreased with the increase of Solanum nigrum L. density, and Solanum nigrum L. had a significant effect on the middle boll number and yield of cotton（P< 0.05）. When the density of Solanum nigrum L. is 1 plant /m², the loss rate of cotton yield is 60.92%. When the density of Solanum nigrum L. reaches 15 plants /m², the loss rate of cotton yield is 100%. The logarithmic regression model was the best in describing the relationship between Solanum nigrum L. density and yield loss as y =12.594ln（x） + 58.025.According to EIL and the logarithmic regression model, the economic threshold for artificial control of Solanum nigrum L. was 0.016 plants/m², and the economic threshold for chemical control by 96% S-metolachlor EC was 0.017 plants/m². 【Conclusion】 The inhibitory effects of Solanum nigrum L. on cotton were positively correlated with its density.According to the economic threshold analysis, when the density of Solanum nigrum L. in the field is higher than 0.016 plant /m²,it should be controlled in time.