摘要
地膜覆盖的增温作用,改善了棉花的生态环境,加快了棉株生长发育的进程;也使降雨和灌溉水的入渗补给过程有所改变,其入渗途径是以垅沟为中心向膜下和地中入渗;地膜的保墒机理,在于地膜覆盖使水汽进入大气的部分通道被地膜所切断,膜内虽因土层温度高而产生大量水汽,但只能沿水平方向通过垄沟表面(未覆盖部分)进行蒸发,从而减少了土壤水分蒸发的数量;共提墒机理,则是地膜覆盖加大了在夜晚、清晨和阴雨天时地中与地表之间的温度梯度(此时地中温度高于地表),在其影响下所产生的上升水汽流,受地膜阻隔,并在膜面附近凝成水滴、滴入土壤,提高了表层土壤的湿度。
Owing to the increase of temperature caused by the film covering, the ecological environment for cotton will be improved, the growth of cotton seedling will be speeded up, and the rainfall and irrigation infiftration will be changed. Generally, the., drops of water infiltrate through the film and into soil centring around the ditch. The moisture-preserving mechanism of the film means, owing to the film covering, the path for vapour into atmosphere will be cut in part and a great deal-of vapour produced by the high temperature beneath the film can only evaporate through the surface of the ditch along the horizontal, reducing, the moisture-evaporating capacity in soil. The moisture-increasing mechanism of the film means, the temperature gradient between the middle and the surface of soil will be increased in night, morning or rainfall days by the film covering (the temperature in the middle of soil being higher than that in the surface of soil at this time), So the uprising vapour will be cut by.the film and condensed into the drops of water near the surface of the film, then the drops driping into soil to increase the moisture of the surface soil,
出处
《灌溉排水》
CSCD
1989年第3期10-17,共8页
Irrigation and Drainage
