交替滴灌对土壤水盐分布规律影响研究

A Study on the Effects of Different Alternate Modes of Drip Irrigation with Saline and Fresh Water on Soil Water-salt Distribution

采用矩形有机玻璃土箱,研究了4种交替模式（咸淡、淡咸、咸淡咸、淡咸淡）下滴灌对土壤水盐分布状况的影响。试验结果表明：交替模式对湿润锋的推进速率在灌水初期0～30min影响较大,淡水较咸水在水平方向推进更快,而咸水较淡水更有利于垂直入渗;对水分、盐分的影响主要体现在2～6cm深度层,咸淡咸的交替模式在该范围内含水率值最大,咸淡次之,第1单项滴灌水的水质对大孔隙的形成起决定性的作用;咸淡及淡咸淡的交替模式在该范围内电导率值较大且淡咸淡的交替模式出现了一个突变的电导率值;最后灌淡水能够有效淋洗咸水聚集在表层的盐分。

The laboratory experiments were conducted to quantify the influences of four alternate modes of drip irrigation（saline-fresh;fresh-saline;saline-fresh-saline;fresh-saline-fresh）on soil water-salt distribution with a rectangular plexiglass container.The results indicated that the modes of alternate drip irrigation had important influence on wetting front advance rates at the beginning;fresh water moved faster than saline water in horizontal direction and saline water was faster in vertical direction;There was an obvious change for water-salt distribution in 2~6cm deep,the alternate mode of saline-fresh-saline had maximum values of soil water content and the saline-fresh took second place,the water quality irrigated in the first step had a very important role in the formation of macropore;The mode of saline-fresh and fresh-saline-fresh had a higher conductivity value in 2~6cm depth and the fresh-saline-fresh mode had a inflection point of electrical conductivity,and the salt held in the surface could be leached that when fresh water was irrigated in the last.