华北高寒区不同潜水位萝卜田耗水特性与覆膜效应研究

 针对华北高寒区蔬菜雨养旱作生产,通过定位观测试验,研究了不同潜水位水平及其地膜覆盖的萝卜田耗水量与耗水组成,菜田耗水的时空特征及覆膜的水分产量效应。结果表明,3 m以下潜水对菜田耗水极少贡献;2 m与1 m潜水位菜田潜蒸水可有25.79 mm与71.78 mm,对萝卜旱作生产具重要作用。萝卜田生育期平均耗水强度2.94 ～3.41 mm·d-1 ,30～60 cm土层是主要供水层次。覆膜萝卜田,较裸地水分蒸失减少15.51～39.19 mm,水分利用效率提高40.00%～81.70%。地膜在萝卜生育期间"前保后供"的土体水分调节效应,成为旱区农作水分时序高效利用的重要机制。

Study on Water Consumption Characteristics and Effects of Film Mulching on Radish Field Under Various Ground Water Tables in the Cold Region of North China

For the success of rainfed cropping in the cold and semiarid region of North China, the characteristics of water consumption on quantity and variation in soil of different depths and the effects of plastic film-mulched radish field were studied. The results showed that little water consumption of radish field came from ground water table at 3 m depth; 25.79 mm and 71.78 mm came from 2 m and 1 m depths respectively. Water consuming ratio was 2.94-3.41 mm·d-1 in radish growing period, and 30-60 cm depth was the main horizon on water supply. Plastic film-mulched radish field decreased water evaporation by 15.51%-39.19% and increased water use efficiency by 40.00 %-81.70% compared with the control. Film mulching plays an important role in water use efficiency in the rainfed farming by the mechanism of storing water in early radish growing stage and supplying it in the late stage.