枣棉间作复合系统种植模式对棉花光合特性及产量的影响

合理的枣棉间作种植模式有利于光资源的利用和产量的提高。为探明枣棉间作系统中棉花产量形成的光合生理机制,筛选出适于南疆的枣棉间作最优种植模式,以枣树-棉花间作模式为研究对象,设离树间距1.4 m(M1)、1.0 m(M2)、0.5 m(M3)3个间作处理,以单作棉花为对照(CK),对棉花冠层上方光合有效辐射(PAR)、棉花叶片净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、胞间CO₂浓度(Ci)5个光合指标及水分利用效率(WUE)和产量进行研究。结果表明,各处理冠层PAR在花铃期达到最大,间作系统冠层PAR总体低于单作,且随离树间距的增加而增大,M3处理PAR最低,分别较M1、M2处理低10.0%和9.5%;间作总体上提高了棉花的Pn,降低了Tr和Ci,M3处理的Gs在2020年最大,2019年最小,并且M3处理的棉花光合能力总体优于其他处理;枣棉间作种植模式有利于提高棉花群体水分利用效率,M3处理的WUE最大,2019和2020年较CK分别提高了52.8%和50.4%;M3处理单位面积内棉花产量最高,分别较CK、M1、M2高18.2%、85.9%和37.0%。灰色关联度分析表明,M3处理表现最优,主要生育期内等权关联序和加权关联序位次总体排第一。综上,适宜的间作种植模式为M3处理。本研究结果为南疆枣棉间作种植模式优化配置提供了理论依据和技术支撑。

Effects of Planting Patterns of Jujube-Cotton Intercropping System on Photosynthetic Characteristics and Yield of Cotton

A reasonable jujube-cotton intercropping planting mode is beneficial to the utilization of light resources and the improvement of yield. In order to explore the photosynthetic physiological mechanism of cotton yield formation in the jujube-cotton intercropping system, and screen out the optimal planting mode of jujube-cotton intercropping suitable for southern Xinjiang, three cotton to jujube spacing of 1.4 m (M1), 1.0 m (M2), 0.5 m (M3) and sole cotton (CK) were adopted to investigate the photosynthetically active radiation (PAR) above the cotton canopy, net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), intercellular CO₂ concentration (Ci), water use efficiency (WUE) and cotton yield. The results showed that the canopy PAR of each treatment reached the maximum in the flowering and boll stage, and the canopy PAR of the intercropping system is generally lower than that of the monocropping, and increased with the increase of the spacing between the jujube and cotton. The PAR of the M3 is the lowest, and are 10.0% and 9.5% lower than M1 and M2, respectively. The Pn increased in the intercropping, whereas Tr and Ci decreased. The Gs of M3 is the largest in 2020 and the smallest in 2019. The photosynthetic capacity of cotton for M3 is generally better than other treatments. The jujube-cotton intercropping can facilitate the water use efficiency (WUE) of cotton, and the WUE of M3 is the highest, which is 52.8% and 50.4% higher than that of CK in 2019 and 2020, respectively. The highest cotton yield per unit area in the intercropping occurred in M3 which was 18.2%, 85.9% and 37.0% higher than that of CK, M1 and M2, respectively. Through the gray correlation analysis, M3 performed the best, ranked first in the equal-weight correlation order and weighted correlation order during the main growth period. A reasonable jujube-cotton intercropping planting mode can prompt the light utilization and increase the yield. In conclusion, the optimal intercropping planting mode is M3 treatment. This research provides theoretical basis and technical support for the optimal configuration of jujube-cotton intercropping planting mode in southern Xinjiang.