干旱区膜下滴灌棉田SPAC系统水分通量模拟

摘要

研究新疆干旱区现行一膜六行滴灌方式下棉田的土壤水分运移过程及SPAC系统水分通量,为实施农业节水策略提供理论依据.在新疆典型棉花种植区田间试验的基础上,通过构建Hydrus-2D土壤水分运移模型,探讨膜下滴灌棉田SPAC系统的水分通量.结果表明,在距地表50 ～ 70 cm处由周期性滴灌产生了一个发散型零通量面.整个模拟期内,灌溉是主要水分输入来源,占模拟区域输入水量的87.6％.70％以上的水量均被作物吸收利用,土壤蒸发量及渗漏量仅分别占8.2％和20.8％.灌溉水的利用效率可达85.2％.综合模拟结果表明现行一膜六行的滴灌方式能有效减少土壤蒸发量及深层渗漏量,提高了区域水资源的利用效率.%Knowledge of the law of soil water movement and SPAC continuum water flux in cotton fields under drip irrigation with the common style of one mulched with six rows in the Xinjiang arid region is of great significance to realize agricultural water-saving irrigation.In this study,soil water numerical model is built with the Hydrus-2D and calibrated with the experimental data to discuss water flux in cotton field SPAC continuum under mulched drip irrigation.The results show that under the periodic irrigation a divergent curved surface of zero flux occurs at a depth of 50-70 cm below the land surface.During the whole simulation period,irrigation is the main source of inflow water,accounting for 87.6％ of the inflow water.More than 70％ of the inflow water is consumed by cotton,while soil evaporation and deep percolation account for only 8.2％ and 20.8％,respectuvely.The utilization efficiency of agricultural water is 85.2％.The simulation results suggest that the current drip irrigation with the style of one mulched with six rows can effectively reduce invalid evaporation and deep percolation and improve the utilization efficiency of irrigation water resource.