紫茎泽兰对棉花生长的影响及经济阈值

Effects of Eupatorium adenophorum on the growth of cotton and its economic threshold

为明确紫茎泽兰Eupatorium adenophorum Spreng在棉田中的经济危害允许水平和经济阈值,采用添加系列试验和模型拟合的方法,在田间条件下研究紫茎泽兰不同密度对棉花的生长性状及产量的影响。在紫茎泽兰的竞争干扰下,棉花果枝数和单株铃数均随着紫茎泽兰密度的增加而逐渐降低。当紫茎泽兰密度达到60株/m2时,棉花果枝数和单株铃数较无紫茎泽兰对照分别减少了22.1%和57.2%,同时棉花皮棉产量损失率也达到57.2%。棉田田间透光率也随紫茎泽兰密度的增加而降低,当紫茎泽兰密度为60株/m2时,其透光率仅为3.5%。幂函数模型y=3.049x1.031能较好地拟合紫茎泽兰密度(x)与棉花产量损失率(y)间的关系。棉田采用人工除草和41%草甘膦异丙胺盐水剂对紫茎泽兰进行防除时,紫茎泽兰的经济危害允许水平分别为8.42%、1.06%,经济阈值则分别为2.68、0.36株/m2。

To determine economic infestation level and economic threshold of Eupatorium adenophorum Spreng in cotton fields, additive series experiment and curve fit were adopted to study the changes of yield characters of cotton under different densities of E. adenophorum in the fields. The results showed that with the interference of E. adenophorum, the cotton fruit branches and boll per plant decreased gradually as the weed density increased. The cotton fruit branches and boll per plant were decreased by 22.1% and 57.2% in 60 plant/mE E. adenophorum treatment compared with untreated control, and the percentage loss of lint yield was also reached up to 57.2%. Light penetration rate in cotton field also decreased sig- nificantly with the increasing weed density, and the light penetration rate was only 3.5% in 60 plant/mE E. adenophorum treatment. The power regression model y = 3. 049x1~31 was relatively better in describing the relationship between E. adenophorum density （x） and yield loss （y） of cotton. The economic infesta- tion levels for the E. adenophorum by manual weeding and glyphosate were 8.42% and 1.06%, respec- tively. And the economic thresholds were 2.68 and 0.36 plant/m2, respectively.