初始湿度对覆膜开孔蒸发水盐运移的影响

Effects of Initial Soil Moisture on the Movement of Soil Water and Soil Salt During Evaporation under Perforated Plastic Nulch

为了解初始含水率(湿度)变化对覆膜开孔蒸发的盐分与蒸发量的定量关系,通过不同湿度土壤的室内蒸发实验,研究了覆膜开孔率影响下土壤水分和盐分的运动特征。结果表明,初始含水率越大,不同覆膜条件下累积蒸发量越大,单位膜孔面积累积蒸发量(ER)随开孔率增大而急剧减小,不同初始湿度的ER与覆膜开孔率的关系可用乘幂表示;表土返盐量随覆膜开孔率的增大而逐渐增加;不同含水率土壤的盐分浓度剖面分布趋势一致,含水率越大,表层盐分浓度越大,含水率较小的土壤,盐分浓度在表层最大,在盐分含量最低点附近达到最小值,表层以下4-13cm的盐分浓度均小于初始值;不同覆膜开孔率条件下不同含水率土体剖面盐分浓度与垂直位置之间可用幂函数表示。研究表明,初始湿度对土壤水盐运动的影响存在定性特征,而覆膜开孔率对水盐运动的影响有定量关系可循。

In order to determine the quantitative relationship of change of initial soil water content （soil moisture） for the soil salt and accumulative evaporation under perforated plastic mulch evaporation,according to indoor soil evaporation experiments of different soil moisture,researched the movement characteristics of soil water and soil salt under perforated plastic mulch. The paper studied the soil moisture and the movement characteristics of soil salt under perforated plastic mulch after evaporation. The results showed that initial soil moisture influence soil water supply capacity in evaporation,the larger of soil moisture,the larger accumulative evaporation under perforated plastic mulch,cumulative evaporation per unit hole area film（ER）rapidly decrease when the open hole ratios increased,the function of ER and the open hole ratios of different soil moisture were established;accumulation of salt in the surface soil gradually increases with the open hole ratios,for the cumulative evaporation of the known soil moisture,it can predict accumulation of salt in the surface soil under perforated plastic mulch;the salt concentration distribution of different soil moisture with one accord,the greater of the soil moisture,the greater of the salt concentration of surface,for smaller soil moisture,salt concentration is largest in the surface and is lowest in the vicinity of the salt content minimum value,the salt concentration is less than the initial value under surface of 4-13 cm depth,there were power function between the salt concentration of different soil moisture and vertical position under perforated plastic mulch. The research showed that there was the specific natural characteristics of initial moisture for the movement of soil water and soil salt,and the specific quantitative relationship of the open hole ratios affected the movement of soil water and soil salt.