| چکیده انگلیسی مقاله |
Iran is located in worldwide erosion belt, and more than 64 percent of its area is consisted of arid and semi-arid areas with no vegetation. These areas are sensitive to wind erosion, and dust storms. Wind erosion is a function of two factors including wind speed and soil erodibility. Reducing the wind speed or increasing surface roughness are strategies to increase soil resistance against winds and controlling the wind erosion. One of the fast and temporary strategy to reduce wind erosion is the use of mulches on the soil surface. Production the cheap, environmental friendly and resistant mulch against the wind forces is vital in short term periods. Bentonite and Zeolite are cheap in Iran, and environmental friendly. Therefore, the aims of this study were to investigate the effectiveness of clay mulches (Bentonite and Zeolite) on wind erosion. For this purpose, soil samples were taken from 0-30 depths of desert region, air-dried and passed through 2 mm sieve to analyze physical and chemical properties of them. The research was carried out as a completely randomized design. Soil was homogenously filled into metal trays (43 cm in length, 25 cm in width and 2 cm in height), and their surface completely leveled. Clay mulches i.e. bentonite at two rates (100 and 200 g + 1000 ml water; B1 and B2), and zeolite at two rates (100 and 200 g + 1000 ml water, Z1 and Z2), and control (1000 ml water) in three replications were prepared. Then the mulches were sprayed on soil surfaces of the trays. The treated trays were located in outdoors to achieve air dry condition for 10 days. The control treatment was simultaneously prepared. Erodibility of treated soils was measured in a wind tunnel. Wind speed of 85 km.h-1 (predominant speed in studied area) was applied to treatments for 20, 40 and 60 minutes. After each time, the amount of the eroded soil from the depository was weighed. Based on analysis of variance the effect of mulch, time and interaction effect of them on soil erosion content were significant at p<0.01. Comparison of means showed that clay mulches significantly reduced the soil erosion content in relation to the control, and Z1, Z2, B1, and B2 treatments had no significant difference (p<0.05). According to these results, the highest reduction of soil erosion was obtained in B2 and B1 treatments, respectively, which was 71.78 and 55 times lower than the control. Regard to the results of wind erosion at all three both B1 and B2 can be considered as the most suitable treatment for controlling wind erosion. The interaction effect of time and mulches showed that the highest and lowest erosion contents were found in control after 40 minutes, and Bentonite after 20 minutes, respectively. In general, it seems that B2 may be the best treatment to reduce soil erosion. |
