کاوشهای جغرافیایی مناطق بیابانی (Oct 2021)
Evaluation of the efficiency of rock mulching method against wind erosion (Case study: Segzi plain and Fasaran plain of Isfahan)
Abstract
Introduction:Sandstorms are natural events that occur in arid and semi-arid regions of the world, especially in subtropical latitudes. The vastness of deserts around the world indicates that these areas have been important sources of dust storms throughout history, but in recent years, human activities have also created another source on the edge of deserts in semi-arid regions. These have been stable. The use of pebble mulch, which is a clear example of inspiration from nature in the field of paving (Hamada). In addition to gravel, one of the materials that can be effective in this way is steel slag, which seems to be usable as a coating to keep particles sensitive to erosion of sandy areas. It also seems to have the ability to create a suitable substrate for the establishment of tropical or native vegetation.In addition, slag seems to have the ability to treat eroded particles and can play an important role in the treatment of Aeolian sediments. Knowledge of the amount and type of particles treated by mulch enhances our overall understanding of its impact on controlling wind erosion and the impact of sediments on soil formation and production in covered lands.Research MethodsIn this study, while determining the threshold of wind erosion in work areas by non-oil sandblasting and mulching in desert areas studied in an area of 1 to 2 hectares (depending on the specific conditions of the region, facilities, natural features and other characteristics of the region) as A research pilot was used to compare their performance in terms of soil containment and stabilization, as well as the costs incurred for each method, and to introduce them to the executive departments of the country for each region according to the specific characteristics of that region.MethodTwo separate factorial experiments in a randomized complete block design with three replications using natural almond pebbles with a density of 75% in Fesaran plain and Mobarakeh Steel Company almonds with a density of 25 and 50% density compared to the control as mulch Were used. The site of the first experiment was Site 1 with an area of about one hectare located in the desertification station of Segzi plain (Figure 1). Factor A was the uniform condition of the area with uniform mulch spraying treatment with a density of 25%, 50% and control. Factor B were two types of sediment traps (tray and polygonal). The plots had dimensions of 20-30 square meters. The shape of the plots was chosen so that the length of the plots was in the direction of the prevailing erosive wind. The distance between the two plots was considered 30 meters so that the effect of mulching on the other plot would not be left. The location of the second experiment was in the Fesaran area. In this experiment, factorial in the form of a randomized block design was used. Factor A mulching with 75% density of pebbles and control and factor B were two types of sediment traps (tray and polygonal).DiscussionThe results of this study showed that mulch reduces the level of wind contact with the soil and increases the roughness and therefore can control wind erosion. Mulch 0 performs two important actions in controlling wind erosion, first it can relieve soil from stress it protects against wind and wind erosion, and the latter can trap wind-blown particles. Segzi and Fesaran plains of Isfahan have erodible sediments and also the movement of wind sand particles. These sediments have a wind erosion threshold of 4.6 meters per second, which is very prone to wind erosion. The treatments in this plan increase the roughness of the soil surface and reduce the wind speed near the ground surface, and as a result, the amount of soil loss is also reduced. As the mulch density increases, less soil erodes due to less area being exposed to the wind. Based on this, the use of pebble mulch, which is a clear example of nature inspiration in the paving areas (Hamada) with the effect of zero (control) and 75% gravel cover density on the area sensitive to wind erosion in Fesaran plain in Isfahan Done. The type of pebbles selected is almond size and the size of gravel and rubble, which was supplied from the nearest sand mines in the region. But in addition to gravel, Mobarakeh steel slags with almond sizes (in order to study and compare costs) with the view of waste with a very large production volume with the effect of zero density (control), 25%, 50% were also used in Segzi plain. In order to create winds with a certain speed at a certain time, a wind erosion measuring device, which is a kind of portable wind tunnel, was used. The lands of mulching sample with different densities are affected by different winds from different directions. The data obtained from the factorial statistical experiments were examined in a completely randomized block design. The results showed a significant difference in the effect of pebble mulch in reducing wind erosion in all studied areas and at a level of less than 1%. Comparison of the effect of molten densities of Mobarakeh steel slags showed that the largest difference between the two densities was 25% and control. The results obtained from the collected data of wooden indices (scavenger traps) in Segzi plain show an average of 1.9 years of wind from the soil surface and in Fesaran plain show an average of 1.2 kg per square meter of wind from the soil surface And the statistics obtained from the tray sediment trap had a better performance than the plastic polygon sediment trap and showed a significant difference. In these two areas, the volume of creep particles is higher and a very large amount of dust has accumulated in the sediment trap. Trap in the process of creeping or jumping by the wind
