南疆膜下滴灌棉花咸淡水轮灌模式研究

Optimizing alternate brackish and freshwater drip irrigation with film mulching for cotton production in Southern Xinjiang

[目的]探究不同咸淡水轮灌方式对南疆膜下滴灌棉田水盐、棉花生长及产量的影响,寻求安全、高效、高产的咸淡水轮灌制度。[方法]以棉花为研究对象,在新疆阿拉尔现代农业综合试验站开展大田试验,试验共设置9个咸淡水轮灌处理,探究不同的咸淡水轮灌处理对土壤水盐、棉花生长及产量的影响。[结果]棉花生育期内,随着灌溉微咸水比例的增大,土壤水盐量呈增加趋势,相同微咸水占比条件下,棉花生育前期连续灌溉淡水有利于降低根区土壤盐分水平。微咸水灌溉占比越大对棉花的生长抑制作用越大,花铃期适量的微咸水灌溉有利于促进棉花的生殖生长,但微咸水灌溉频率过高会显著降低棉花的单铃质量。适宜的咸淡水轮灌方式既要保证棉花生育前期的营养生长也要在花铃期适时适量灌溉微咸水以促进棉花生殖生长。[结论]南疆棉花种植中,灌溉微咸水占比不宜过高,建议在苗期、蕾期及花铃前期减少微咸水灌溉频率,在花铃期适当提高微咸水灌溉频率。本研究中最优的咸淡水轮灌处理为“淡淡咸”处理。

【Objective】Southern Xinjiang has limited freshwater but relatively abundant saline groundwater.To optimize the use of these water resources,we investigate the effect of alternate brackish and freshwater drip irrigation with film mulching on soil water and salt movement,as well as seed yield of cotton.【Method】The experiment was conducted at the Xinjiang Alar Modern Agricultural Comprehensive Experimental Station.It compared nine combinations of brackish and freshwater drip irrigation.In each treatment,we measured the spatiotemporal changes in soil water and salt,as well as growth,and seed yield of the cotton.【Result】During the growth period of the cotton,soil water and salt increased with increased use of brackish water.When the amount of brackish water used for irrigation was the same,continuous use of freshwater irrigation in the early growth stage of the cotton was effective to reduce salt content in the root zone.Increasing the use of brackish water in irrigation inhibited crop growth.Moderate use of brackish water in the flowering and boll development stages can promote reproductive growth,however,excessive use would significantly reduce the weight of single bolls.Appropriately alternating brackish and freshwater irrigation not only ensures vegetative growth in the early stages but also promotes reproductive growth during flowering and boll development stage of the cotton.【Conclusion】In Southern Xinjiang,alternating brackish and freshwater in drip irrigation with film mulching should keep the brackish water ratio below a specific threshold.Its usage should be minimized during the seedling,budding,and early flowering stages,but can be increased during the flowering and boll development stages.In this experiment,the optimal irrigation sequence was freshwater-freshwater-brackish water.