Possibility of self-mulching material of Tottori sand dune soil to reduce soil evaporation

摘要

In this study the possibility of the quick development of a dry layer and quick cover of the Tottori sand dune soil was evaluated to identify its suitability as a self-mulching material to reduce soil evaporation. The effect of a dry surface layer onsoil evaporation reduction was also evaluated. Water was applied to the field capacity of the sand soil and that was naturally dried. The temporal water content profile below the surface showed that the sand soil in the top layer dried in 3 to 5 days after water application and formed a dry layer near the surface that covered the lower wet layer. The thickness of the dry layer was about 4 cm in our experiment conducted in May 2008. It was clear that the sand soil had a self-mulching effect. In order toevaluate the effect of the dry layer on reducing soil evaporation, soil coluiim experiments were carried out for both controlled and uncontrolled conditions. Sand soil columns were saturated and gravitational water was drained. Then, the sand soil columns were covered with a 2 cm and 5 cm thickness of dry sand soil. Evaporation reductions were observed at both thicknesses. The 5 cm thickness was more effective (than the 2 cm), with a reduction of more than 72 % compared to no cover.