Column Experiments on the Salt Accumulation in Adjoining Different-Textured Soil Profiles with a Shallow Water Table

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Two column experiments on the relation between soil texture and salinization in soil profiles with a shallow water table were conducted under rainless conditions using the concept of ECSAT. The buildup of salts due to evaporation from bare soil was confined within the superficial layer and its amount during a period could be assumed to equal the product of the total of evaporation during the period and the salinity of water supplied into the soil profile, such as irrigation water and/or groundwater. This amount of salt accumulation became larger on the portions consisting of fine-textured soils than of coarse-textured soils in course of time from a heavy irrigation. The shape of the depth profile of ECSAT obtained in these experiments was similar to the actual shape observed at cornfields in the Yellow River valley (Kobayashi et al., 2006b). The least salt-affected layer appeared just beneath the surface layer, below which ECSAT increased with increasing depth to the EC of groundwater (ECGW). This suggests that the existence of the soil layer with ECSAT larger than ECGW is a sign of inadequate leaching of salts.
2008-10-28