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黄顶菊是近年在我国发现的外来入侵植物,在河北省已进入农田。为明确黄顶菊在棉田中的经济危害允许水平、经济阈值以及竞争临界期,采用添加系列试验和模型拟合的方法,在田间条件下研究黄顶菊不同密度对棉花的生长性状及产量的影响。结果表明,在黄顶菊的竞争干扰下,棉花的叶面积指数、田间透光率、水分利用效率、氮素利用效率和棉花产量均随黄顶菊密度的增加而逐渐降低。当黄顶菊密度为5株/m2时,叶面积指数、田间透光率、水分利用效率和氮素利用效率显著低于无黄顶菊对照;当密度为2株/m2时,棉花产量显著低于无黄顶菊对照。对数函数模型可以较好地拟合黄顶菊密度与棉花产量损失间的关系(y=22.79lnx+9.0277,R=0.9759)。棉田中黄顶菊的经济危害允许水平为0.66%～3.06%,经济阈值为0.69～0.77株/m2,与棉花的竞争临界期为棉花播种后5.15～83.13天。
Flaveria bidentis is a invasive alien plant found in China in recent years and has entered farmland in Hebei Province. In order to clarify the permissible economic threshold, economic threshold and competition critical period of cotton, the effects of different density of flaveria bidentis on the growth and yield of cotton were studied under field conditions by adding series of experiments and model fitting methods. The results showed that under the disturbance of flaveria bidentis, the leaf area index, field transmittance, water use efficiency, nitrogen use efficiency and cotton yield decreased with the increase of the density of Flaveria bidentis. When the density of Flaveria bidentis was 5 plants / m2, the leaf area index, field transmittance, water use efficiency and nitrogen use efficiency were significantly lower than those without broomthrin. When the density was 2 plants / m2, the cotton yield was significantly lower than that without borage Control. The logarithmic function model could well fit the relationship between the density of flavethrin and the yield loss of cotton (y = 22.79lnx + 9.0277, R = 0.9759). The economic hazard of flaveria bivalvia in cotton field was 0.66% ~ 3.06%, the economic threshold was 0.69 ~ 0.77 plant / m2, the critical period of competition with cotton was 5.15 ~ 83.13 days after sowing cotton.