Investigating the effect of gravelly filters in rainwater harvesting systems to optimize infiltration and increase soil moisture storage in rainfed gardens

This research has been carried out with the aim of investigating the use of gravelly filters in rainfed gardens on sloping lands in order to optimize infiltration and increase soil moisture storage in the conditions of using micro catchment systems during the years 2013-2018 in Chaharmahal and Bakhtiari province. The research rejoin has an average annual rainfall of 300 mm, soil with silty clay loam texture, and an average slope of 15%. Towards this attempt, micro catchments were made with five different treatments including a removed surface with and without using a gravelly filter, an isolated surface with and without using a gravelly filter, and the control treatment(natural surface), along with three cultivars of almond(Rabie, Mamaei, and Shahroud 21) and were constructed in 5 repetitions. The soil moisture at the depths of 25, 50, and 75 cm of the seedling hole in each of the systems was accurately measured and recorded using a TDR device. In order to determine the role of filters and to determine the difference between similar treatments with the different presence or absence of gravelly filters in them, Paired-Samples T-Test was used in SPSS software. The results showed that there is a significant difference between the treatments with filter and without filter in terms of soil moisture percentage. In other words, using the gravelly filter in the seedling pit will optimize the infiltration of extracted runoff into the soil, increase humidity in the place of tree root development, and increase its growth. Therefore, it is recommended to use the gravelly filter in the seedling pit in the conditions of using rainwater catchment systems.