| 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. |