Feasibility investigation of FilterCake using in mulch production for sand dune stabilization in Ahvaz

Wind erosion is not only a basic geomorphic process of eroding and altering landforms but also one of the main causes of sandy desertification in arid and semiarid areas (Chepil 1945; Nordstrom and Hotta 2004). Single-grained، fine sand dunes are usually composed of none-strength materials with a low water retention that make them susceptible to wind erosion. They lack organic matter and are inherently of low fertility (Ahmadi، 2002). Therefore، sand dunes and drift areas require non-oil artificial covers for their stabilization and that of the vegetation cover (Rezaie، 2009). The covering material types include oil (Rezaie، 2009)، flat crop residues (Chepil، 1944; Bilbro and Fryrear، 1994)، standing residues (Siddoway et al.، 1965; Bilbro and Fryrear، 1994)، pebble (Li et al.، 2001)، cotton gin trash، clay، gravel، picket fence، brush، straw، and hay (Fryrear، 1985). Soil properties including compressive strength، plasticity، compactibility، strength characteristics، elastic modulus، crushing strength، unconfined compressive strength، erodibility، shear strength، and permeability have been investigated for evaluating mulch effectiveness. Improvements have been achieved in sand dune stabilization by decreasing permeability and enhancing strength properties. The effect of soil properties on wind erosion has been studied through shear strength of soil surface which includes a frictional term (due to inter-particle frictional strength) and a cohesive term (due to intrinsic bonds among particles) (Koolen and Kuipers، 1983; Alizade، 2009). As regards the factors influencing soil shear strength، soil particle diameter، bulk density، cohesion، aggregate index، water content، crust، and organic matter have all been found to influence wind erosion (Raji et al.، 2004; Homauoni and Yasrobi، 2011). Based on these observations، it may be hypothesized that soil cohesion caused by mulching operations could be effective in reducing wind erosion. Filter Cake is residue produced in huge amounts by the agro-industry that is composed of cellulosic substances، CaCO3، N، P، K، organic matter، and clay. The objective of this research is feasibility of Filter Cake using as a Khuzestan sugarcane residues for adopted-environmental mulch production. For this purpose، Factorial experiments in completely random design form were conducted that factors included mulch kind (5 organic mulch and oil mulch)، thickness (1 or 2 layers) and precipitation. In this study، Filter cake and clay soil samples (Albaji-Ahvaz) were used to make sugarcane mulches. A sand dune sample was selected as bed for applying the mulch. To select the right ingredient and treatments، Filter cake، clay samples were mixed with water in try and error، and producted suspension sprayed on sand dune bed. Surface surface soil shear strength، penetration resistance، soil adhesion and mulch’s internal frictional angle and erodibility were measured by shear vane، penetrometer، Zhang’s shear device، wind tunnel respectively. The results determined that there is significant effect (p<0. 01) on surface shear strength and penetration resistance in different much and thickness. But there is no significant effect on soil adhesion and mulch’s internal frictional angle because Zhang’s shear device hasn’t essential sensitive to differentiate them. Based on this research، Mulch 1 (50g clay+150 g Filter Cake) is selected as superior mulch in Ahvaz sand dune stabilization because of higher surface shear strength and penetration resistance rate. It is defined as the resistance soil materials can offer against shear stress. This property is directly related to the cohesive and friction forces between soil particles (Koolen and Kuipers، 1983; Knapen et al.، 2007; Khalilmoghadam et al.، 2009) and، thereby، related to soil intrinsic properties such as clay content، salinity، and organic matter content (Horn et al.، 1994). Sugarcane residues due to their effects on cohesive forces affect soil strength via the physical and chemical properties of Filter Cake. In this study، increases in SAR were found to be inversely proportional to SSS and PR. With identical values of SAR، treatments with higher EC values exhibited greater saturated SSS and PR. This shows the adjusting effect of EC on SAR effects. It is، therefore، concluded that the combined Filter Cake and clay soil could strongly affect soil resistance to erosive shearing stresses and wind erosion under environmental conditions. Sugarcane mulches were shown to be effective in stabilizing sand dunes as compared to oil mulches. It is، therefore، concluded that the combined Filter Cake strongly influence to erode under environmental conditions.