膜下滴灌滴水流量对棉花根系分布的影响

为探明膜下滴灌条件下滴水流量对棉花根系分布的影响，采用田间定位试验，设置3组滴水流量，分别为1.69 L·h^-1（W169）、3.46 L·h^-1（W346）和6.33 L·h^-1（W633），分析膜下滴灌土壤水吸力对棉花根系空间分布特征的影响。结果表明：滴水流量越大，膜外裸地和膜内土壤的基质吸力越小，边行棉花根系吸水受到的胁迫程度也越小，W633处理膜下根区土壤水吸力分布均匀且适合棉花生长，棉花根长密度水平分布不论是初期还是后期均呈双峰抛物线分布；棉花根重密度呈现出相同的变化规律，内、边行棉花根重密度在花期、铃期、吐絮期的差值分别为42.26、-0.22、97.40 g·m^-3。当滴水流量越小时，膜外裸地的基质吸力大于膜内土壤的基质吸力，致使边行棉花的根系吸水受到较大胁迫，W169处理棉花根长密度水平分布由生育初期的双峰抛物线分布变为后期的单峰抛物线分布；内、边行棉花根重密度在花期、铃期、吐絮期的差值分别为299.70、304.86、369.84 g·m^-3。表明随着滴水流量的增加，膜下滴灌行间棉花根系生长更加均匀，研究结果可为棉花膜下滴灌系统设计提供技术参考。

Effects of drip flow rate of mulched drip irrigation on root distribution of cotton

The purpose of this study to conduct field location experiments with three emitter flows of 1.69 L·h^-1 (W169), 3.46 L·h^-1 (W346) and 6.33 L·h^-1 (W633) to explore the effects of soil water suction on the spatial distribution characteristics of cotton roots under mulched drip irrigation. The results showed that the larger the drip irrigation flow, the smaller the matrix suction of the bare land outside the film and the soil within the film, and the smaller the water stress of lateral cotton roots. The soil water suction in the root area of W633 was uniformly distributed, suitable for cotton growth, and the long density horizontal distribution of cotton roots showed a bimodal parabola in the early and late stages. The root weight density also showed the same change trend, and the difference values of root weight density between the inner cotton roots and lateral cotton roots at the flowering, boll formation and boll opening stages were 42.26 g·m^-3, -0.22 g·m^-3 and 97.40 g·m^-3, respectively. When the drip irrigation flow was small, the matrix suction of the bare land under the film was greater than that of the soil under the film, resulting in the increase of water stress of lateral cotton roots. The long density horizontal distribution of cotton roots treated with W169 changed from a bimodal parabola in the early stage of growth to a unimodal parabola in the late stage, and the difference values of root weight density between the inner cotton roots and lateral cotton roots at the flowering, boll formation and boll opening stages were 299.70 g·m^-3, 304.86 g·m^-3 and 369.84 g·m^-3, respectively. The results indicated that with the increase of drip irrigation flow, the growth of cotton row roots under mulched drip irrigation became more uniform. The results can provide technical references for the design of mulched drip irrigation system.