干旱区绿洲膜下滴灌棉田蒸散发

Study on evapotranspiration of cotton field under drip irrigation in oasis of arid region

蒸散发是干旱区农田水循环过程中水分消耗的主要途径,对研究气候变化下干旱区农田耗水规律和制定科学的灌溉制度有重要作用。连续3 a利用大型称重式蒸渗仪监测滴灌棉田蒸散发,设置覆膜与不覆膜对比试验,研究蒸散发过程,分析覆膜和气象因素对蒸散发的影响。结果表明:(1)在棉花整个生育期内,覆膜与不覆膜滴灌棉田的平均蒸散量分别为292.15 mm和429.22 mm,膜下滴灌的种植方式可以降低31.93%的蒸散量。(2)蒸散量和蒸散强度在不同生育阶段的大小关系:花铃期>蕾期>吐絮期>苗期。(3)滴灌棉田在00:00—08:00进行凝结,在08:00—23:00进行蒸散发,蒸散量在午后达到最大值,苗期最大值出现最早,花铃期最大值出现最晚。(4)蒸散发与风速、辐射、气温呈正相关;与湿度和气压呈负相关。(5)降雨会促进滴灌棉田蒸散发。总体而言,覆膜可以减少水分蒸散发,有助于提升农业生产过程中的水分利用效率。

Crop evapotranspiration is the main way of water consumption in the process of farmland water cycle in arid region.It plays an important role in the study of the law of water consumption and formulating scientific irrigation systems under climate change in arid regions.A large-scale weighing lysimeter was used to monitor evapotranspiration of drip irrigation cotton field for 3 consecutive years.Drip irrigation under mulch film and no mulch film were compared to analyze the influence of film mulching and meteorological factors on evapotranspiration.Results showed that(1)in the whole growth period of cotton,the average evapotranspiration of drip irrigation cotton field under mulch film and under no mulch film were 292.15 and 429.22 mm,respectively.The method of drip irrigation under mulch film can reduce evapotranspiration by 31.95%.(2)The relationship between evapotranspiration and evapotranspiration intensity in different growth stages was as follows:blooming and boll stage>budding stage>boll opening stage>seedling stage.(3)The drip irrigation cotton field condenses from 00:00 to 08:00 and evaporated and transpired from 08:00 to 23:00.The evapotranspiration reached the maximum in the afternoon.The maximum appeared at the earliest stage in seedling stage,and at the latest in blooming and boll stage.(4)Evapotranspiration is positively correlated with wind speed,radiation,and temperature and negatively correlated with humidity and air pressure.(5)Rainfall can promote evapotranspiration in cotton fields under drip irrigation.Overall,drip irrigation under mulch film can effectively reduce the evaporation and improve the water use efficiency in the process of agricultural production.