地表滴灌条件下滴灌量对土壤水分入渗、再分布过程的影响

Effects of irrigation amount on soil water infiltration and redistribution under drip irrigation

在新疆林业科学院枣树示范基地进行了原位土的单点源滴灌试验,研究不同滴灌量条件下地表滴灌湿润体特征值的变化规律。结果表明:滴灌过程中,当滴灌量较小时,湿润体呈平卧半椭球体分布,随着滴灌量的增大,湿润体呈直立半椭球体分布,湿润体的形状大小受到滴灌量和土壤质地的影响,湿润锋水平运移距离与入渗时间存在显著的对数函数关系;湿润体再分布时间为滴灌停止后的12 h内,滴灌过程中土壤含水率以及土壤含水量变化率在滴头正下方40 cm处达到最大值,滴灌量(Q)≥72 L时,水平再分布距离不再随着滴灌量增大而增加;土壤质地以及土壤层的分布直接影响到含水量变化率。

The objective of the study was to investigate the effects of irrigation amount on characteristic of wetting front in a sand soil at a Jujube demonstration base of Xinjiang Academy of Forestry Sciences. The results show that initial drip irrigation wetting front was lying semi-elliptical when irrigation amount is relatively small. With the increase of drip irrigation amount, the wetting front was erect semi ellipsoid distribution. The wetting front shape and size was affected by irrigation amount and soil texture. A logarithmic function could be used to fit the relationship between wetting front distance and infiltration time. The redistribution time was 12 hours after the end of the drip irrigation. Both soil water content and the change rate of soil water content was maximum at 40 cm depth immediately underneath the dripper. The distance of the horizontal wetting front did not expand with the increase of drip irrigation when irrigation amount was beyond 72 L. Soil texture and distribution of soil layer directly affected the change of water content.