The effect of rainwater catchment systems on increasing soil moisture and growth of Elaeagnus angustifolia in Oun Ibn Ali, Tabriz

The lack of stored soil moisture due to the reduction of rainfall and runoff during the growing season as well as inappropriate distribution of the rainfall is an important factor that affects the establishment of vegetation cover and the production of the plant species. Hence, the application of integrated methods for appropriate and optimized use of the rainfall provides suitable conditions to irrigate dry land gardens, especially in cases that the intensity and duration of the rainfall do not result in suitable runoff. The study of vegetation cover and dry land gardens on the southern hillside of Oun Ibn Ali showed that precipitation and runoff reduction are one of the most important factors preventing the development of vegetation cover and dry land gardens in this area. This present research intends to provide the soil moisture content required for plant species in the region via the optimized use of the rainfall and help to solve this problem. The statistical model of this research was performed in the form of a randomized complete block design with three treatments. The first treatment was control treatment (A), which consists of Buckthorn tree (as a resistant plant to water scarcity and widely used plant in the mountain environment), soil of pit and rotting animal manure as 25 % of the whole of the pit. The second treatment (B) was water harvesting insulator surface system accompanied with Pomis at the end of the system. Water harvesting insulator surface system without Pomis at the end of the system was the third treatment (C). The research was performed during 2011 to 2013 in the Oun Ibn Ali region. The dimensions and shape of plots were 7*5 and rectangle. In addition, they were built on a slope about 30%. The height, collar diameter and leaf area were taken from Oleaster (Elaeagnus angustifolia) trees and soil moisture was also measured using a TDR device during the execution of the research. In this plan, the selection of Elaeagnus angustifolia is due to its resistance to drought and the use of this plant in the vegetation cover of Oun Ibn Ali. The results showed that the use of these treatments increased the soil moisture statistically significant at1 and 5 percent compared to control treatment. Comparing the volumetric moisture average of two years revealed that water harvesting insulator surface system accompanied with Pomis at the end of the system treatment had the maximum stored moisture and without Pomis and control treatments were observed in the next order, respectively. Moreover, the effect of the experimental treatments on the height, collar diameter and leaf area of Oleaster tree was significant at 1 %. The maximum and minimum of the height, collar diameter and leaf area belong to water harvesting insulator surface system accompanied with Pomis at the end of the system and control treatments, respectively. Therefore, it is recommended to use this method to create green space in this area.