外来入侵杂草黄顶菊与棉花的竞争作用

Competition of an Alien Invasive Weed Flaveria bidentis with Cotton

研究了外来入侵杂草黄顶菊不同密度、不同共生期对棉花生长的影响,结果表明当黄顶菊密度达0.5株.m-1行长以上时,棉花现蕾期明显推迟,茎秆变细、果枝数、蕾铃数等产量因子显著降低,但株高、4 m行长棉株数和纤维品质未受明显影响;黄顶菊与棉花共生期达4周以上,棉花主茎直径明显下降,共生期达8周以上棉花产量显著降低。由此得出,黄顶菊对棉花具有较强的入侵性和竞争性,应在密度低于0.5株.m-1行长、共生期达8周前进行防除,初步确定其棉田防除经济阈值为0.25株.m-1行长。

The effects of an alien invasive weed Flaveria bidentis with different densities or symbiotic periods on the growth of cotton were studied in cotton field. The results indicated that the cotton budding stage was postponed with increasing weed density up to 0.5 plants ·m-1 of row; Meanwhile, stem diameter, sympodial branch number, and square and boll number were reduced. However, plant height, number of plants per 4 m of row and fiber quality could not be affected obviously. If the symbiotic period for cotton and F. bidentis over four weeks, cotton stem diameter decreased obviously. When the symbiotic period was over eight weeks, the cotton yield was decreased sharply. In conclusion, Flaveria bidentis are strong invasive and competitive to cotton, and should be controlled before its density to 0.5 plants per meter of row and the symbiotic period to eight weeks. And primarily determined the economic threshold was 0.25 plants.m-1 of row.