化学调控对干旱后棉花冠层时空分布及产量的影响

为探究干旱后棉花化学调控增产稳产的可行性,通过模拟田间干旱,采用裂区设计,探究化学调控下干旱后棉花冠层时空分布及产量变化。主区设置人工打顶与化学封顶,副区设置干旱后复水3 d、6 d、9 d喷施低量缩节胺及空白对照。结果表明:喷施缩节胺显著提高棉花籽棉产量、叶绿素相对含量(SPAD)、冠层中上部比叶重及各部位平均叶簇倾角和散射辐射透过系数(TC),显著降低冠层下部、上部叶面积指数,并随喷施时间的提前效果更显著。化学封顶显著增加冠层中下部比叶重、下部叶面积指数、上部叶面积指数及各部位TC。干旱后复水6 d喷施缩节胺,采用化学封顶,棉花SPAD值和比叶重较高,叶面积指数分布均匀,叶片保持直立,冠层整体通风良好,棉花产量最高。

Effects of Chemical Regulation on Spatiotemporal Distribution of Cotton Canopy and Yield after Drought

To explore the feasibilty of chemical regulation for increasing and stabilizing the yield of cotton after drought,field drought was simulated and split block design was used to investigate the effects of chemical regulation on the spatiotemporal distribution and yield of cotton canopy after drought.The manual topping and chemical capping were set up in the main areas,while low-quantity mepiquat chloride was applied to the secondary area 3 d,6 d and 9 d after post-drought re-watering and a blank control.The results showed that mepiquat chloride significantly increased the yield of cotton and seed cotton,the relative chlorophyll content(SPAD),the specific leaf weight(SLW) at the middle and upper parts of the canopy,the mean foliage inclination angle(MIFA) of each part and the transmission coefficient for diffuse penetration(TC),and significantly reduced the leaf area index(LAI) at the upper and lower parts of the canopy.Also,the effect was better if the mepiquat chloride was applied earlier.Chemical capping significantly increased the SLW at the middle and lower parts of the canopy,the LAI at the lower and upper parts of the canopy,and the TC at each part.Mepiquat chloride was applied 6 d after post-drought,re-watering and chemical capping was adopted.The SPAD and SLW of cotton were relatively high,while the LAI was evenly distributed,the leaves were upright,the overall canopy was well ventilated,and the cotton yield reached a maximum.