Impact of grazing on chemical, physical and biological properties of soils in the mountain rangelands of Sahand, Iran

Abstract

The objective of this study was to characterise the effect of grazing on soil physical, chemical and biological properties of a semi-steppe rangeland grazed by goats and sheep in the Sahand Mountains (Iran) in order to develop effective soil conservation measures and sustain livestock production. Grazing was classified as light, moderate and heavy according to the stocking rate and utilisation rate of the vegetation. Soil sampling was conducted at depths of 0–10 and 10–20 cm for each grazing treatment. Soil physical and chemical properties were determined at both depths and soil microbial variables were evaluated at the surface layer. Increasing level of grazing significantly decreased all soil chemical properties at both depths except for pH and magnesium concentration. Increasing the level of grazing significantly decreased the soil moisture content and porosity at both soil depths. The highest values of microbial biomass carbon, total fungi and bacteria were observed on the light treatment. Grazing significantly affected soil properties unfavourably and reduced vegetation vigour and composition, jeopardising the sustainability of the ecosystem.