不同覆膜开孔率下土壤水分和潜水蒸发的模拟研究

为研究蒸发阶段不同覆膜开孔条件下土壤水分运动,在室内进行蒸发模拟试验的基础上,采用HYDRUS-1D模型对不同覆膜开孔率和大气蒸发能力条件下土壤剖面含水率和潜水蒸发量动态变化进行了模拟,并与实测资料进行比较。结果表明:土壤剖面含水率同时受大气蒸发能力和覆膜开孔率的共同作用,随覆膜开孔率和大气蒸发能力的增加,土壤剖面含水率减小,且上层土壤含水率差异比下层土壤明显;覆膜开孔率和大气蒸发能力一定时,土壤剖面含水率在蒸发初期有所增加,蒸发后期基本保持稳定;覆膜对潜水蒸发的阻滞作用明显,但开孔率增加到一定数值时,表层盐分的影响大于覆膜的影响,使土壤含水率增大,累积蒸发量减小。经实测数据验证,模型精度较好,表明HYDRUS-1D模型用于不同覆膜开孔率下的土壤水分运动模拟是可行的。

Simulated Study on Soil Moisture and Phreatic Evaporation Under Different Aperture Ratios of Film Mulching

The purpose of this study was to investigate dynamic variations of soil water under the phreatic evaporation with different aperture ratios of plastic mulch. Based on column simulation laboratory indoors, HYDRUS-1D model was used to simulate variations of soil water content under different aperture ratios of plastic mulch and atmospheric evaporation capacity, and then the result was compared with the measured data.The results indicated that soil water content was affected by both aperture ratio of plastic mulch and atmospheric evaporation capacity.The soil water content decreased with the increase of the aperture ratios of plastic mulch and atmospheric evaporation capacity with the same depth of soil profile. The fluctuations of soil water content in the upper layer was more obvious than that in the lower layer. When the aperture ratio of plastic mulch and atmospheric evaporation capacity was fixed, the soil water content increased in the early evaporation period and remained stable in the later evaporation period. The evaporation was obviously inhibited by plastic mulch, but when the opening rate of mulching increases to a certain value, the effect of surface salinity on soil evaporation is greater than that of mulching. Mulching increases soil moisture content and decreases cumulative evaporation. The simulation precision of model which was checked by the measured data was well. So it is feasible with HYDRUS-1D model to simulate soil water movement under different aperture ratios of plastic mulch.