Effects of soil characteristics on available soil moisture and Bromus tomentellus forage production (Case study: Hasanjun basin in Taleghan region)

Available soil moisture has great influence on rangeland production and it highly depends on the types of soil texture. This study aimed to evaluate the effects of soil texture on Bromus tomentellus yield. The relationships between some soil properties with soil texture were also studied. Geomorphology methods and GIS techniques were used to provide land unit maps in scale of 1:25000. In each unit, the amounts of pH, EC, N, P, K, OC, %CaCo3 and soil texture of soil samples were measured. The B. tomentellus yield was also measured in all unites. Vegetation cover of the species were then studied in 15 plots (1m2) along two 150 meters transects. Analysis of variance and Duncan test were used to compare the water availability in different soil textures. According to the results, soil water capacity in “clay” and “loamy sand soils” were 0.2 % and 0.1% respectively. It indicated that clay soils are able to store higher water contents. Electrical conductivity, pH, and organic carbons of soil samples in different texture types did not vary significantly but other studied soil properties were different. The land units dominated by “loam” and “loamy sand” soil texture had highest 18/63 kg/hec) and lowest (3/71 kg/hec) B. tomentellus yields.