滴灌覆膜开孔蒸发三维空间水盐运移实验研究

通过滴灌入渗结束的覆膜开孔蒸发实验,分析了土表覆膜开孔率对累积蒸发量随时间变化趋势的影响。累积蒸发量与时间平方根的线性关系符合Gardner的理论关系,而两者关系的系数又与覆膜开孔率之间存在良好的对数关系,从而得出了累积蒸发量的两因素函数关系。这一结果发展了Gardner的理论关系并将其应用于覆膜开孔蒸发的实践上。对相对累积蒸发量和单位膜孔面积的累积蒸发量随开孔率变化的函数特征进行了定量分析,并分析比较了全覆膜和不覆膜蒸发条件下含水率、含盐率和盐分浓度特征,做出了相应水盐特征的等值线图。

Experimental Study on Soil Water Movement and Salt Transport Characteristics of Evaporation from Film Holes in Perforated Plastic Mulch after Trickle Infiltration

Based on experiments of evaporation with different open hole ratios after trickle irrigation, the influence of open hole ratio on cumulative evaporation was analyzed. The results showed that there was good linear relation of cumulative evaporation with square root of evaporation time, and the coefficients of them had good relation with the open hole ratio, thus the two-factor function of cumulative evaporation was obtained. The relation of cumulative evaporation with time was corresponding to Gardner's theoretical function of bare soil evaporation, and the two-factor function of cumulative evaporation extended Gardner's theory and made it practical in film hole evaporation. Theveafter, the functional characteristics of relatively cumulative evaporation and cumulative evaporation on per film hole area varying with film hole ratios were analyzed, and the distributions of soil water content, soil salt content and soil salt concentration of bare soil evaporation were compared with those of evaporation under entirely plastic mulch. Finally the contour maps were drawn out.