机采棉种植模式对脱叶剂雾滴截获、脱叶效果和产量的影响

Effects of planting patterns on the interception of defoliant droplets,the defoliation efficiency and yield of machine-picked cotton

为了明确机采棉种植模式对脱叶质量和棉花产量的影响,开展一膜三行(76 cm等行距)和一膜六行(66+10 cm宽窄行)2种种植模式田间试验,测定了棉花叶片尺度的脱叶剂雾滴粒径分布、覆盖率和沉积量,统计了棉花冠层脱叶剂雾滴的截获沉积、空间分布和地面损失特性,分析了对脱叶效果和棉花产量的影响。结果表明:种植模式对脱叶剂雾滴的粒径分布、截获沉积和空间分布均有显著影响。与一膜六行模式相比,一膜三行模式下棉花叶片所截获的雾滴粒径显著增加(P<0.01),雾滴覆盖率和沉积量分别提高31%和83%,冠层内雾滴分布更加均匀,但冠层地面的雾滴损失量是一膜六行的3.5倍。一膜三行模式可以提升脱叶剂喷施14 d内的脱叶率,但最终脱叶率在2种模式间差异不超过3%,无显著差异。一膜三行较一膜六行模式的产量下降了8.6%(2020)和提升了5.0%(2021)。因此,一膜三行机采棉种植模式能有效改善脱叶剂雾滴在棉花冠层内的截获-沉积特性,有利于促进机采棉早期快速脱叶。

In order to clarify the effects of planting patterns on the defoliation quality and the yield of cotton,field experiments were carried out in two planting patterns:one film with three rows of equal spacing(76 cm,TR)and one film with six rows of wide-narrow spacing(66+10 cm,SR).The volume diameter,coverage and defoliation of defoliant spray droplet were measured for each leaf.The effects of planting patterns on the interception and distribution of defoliant droplets were calculated and on the defoliation efficiency and the yield of the cotton were analyzed.The results showed that the planting patterns had a significant effect on the interception and distribution of defoliant droplets in the cotton canopy.Compared to the SR,the volume diameter of defoliant spray droplets intercepted by the cotton canopy leaves of TR increased significantly(P<0.01),and the coverage and deposition of defoliant droplet also increased by 31%and 83%,respectively.The coverage rate and deposition amount of defoliant droplets were more uniform in the TR,though the amount of spray drop loss to the ground of TR was 3.5 times of that for the SR.Within 14 days of chemical defoliant application,the defoliation rate of cotton canopy in TR was greater than that in SR.However,the difference of defoliation rate between the two planting patterns did not exceed 3%and was not significant.The yield of TR decreased by 8.6%(2020)and increased by 5.0%(2021)compared with SR.This study showed that the planting pattern of TR could effectively improve the interception-deposition characteristics of defoliant droplets in the cotton canopy,which has positive significance in promoting early and rapid defoliation of machine picked cotton.