Investigation of the Gravel Filters and Plastic Mulch Effects in Improving Soil Infiltration and Moisture Storage in Rainwater Harvesting Systems in Steep Lands

       In this study, the possibility of using a combination of gravel filters with plastic cover to increase water infiltration and soil moisture storage in rainwater catchment systems was investigated. For this purpose, five treatments (with three replications) including control treatment, vegetation removal with filter, vegetation removal without filter, semi-insulated system with filter, and semi-insulated system without filter were considered, and Apricot was planted in all treatments. Then, soil moisture storage was recorded by the soil moisture data recorder at two depths of 20 and 60 cm in each treatment. The data were analyzed using a completely randomized block design. The results showed that there was a significant difference between treatments. During the growing season, the highest soil moisture storage was related to the dry months of the year (June, July, August and September) and semi-insulated treatment with gravel filter. In other words, the moisture content of semi-insulated system with gravel filter was significantly higher than other treatments. The results of this study indicated that rainwater harvesting through semi-insulated surfaces and infiltrating it by gravel filter is a good way to increase soil moisture storage.