Effects of Grazing on Soil Characteristics of Winter Rangeland

Grazing animals have either positive or negative impacts on soils just based on grazing time and intensity, climate and soil conditions. Grazing over wet soils usually have negative impacts on soil characteristics. This study was conducted to determine the effects of winter sheep grazing on soil physical and chemical characteristics. Soil samples were taken from 0-5 and 5-15 cm soil depth at the beginning and end of experiments. Merino sheep were grazed for 2 months (January and February) over a rangeland as to have 875 m2 space for each sheep. Paired sample t-test results revealed that grazing had significant effects on bulk density, penetrometer resistance, soil moisture, number of microorganisms and catalase enzyme activities (P<0.05). Grazing did not have any significant effects on the other parameters (aggregate stability, organic carbon(C), total nitrogen(N), urease activity). It was concluded that rangelands should not be grazed under wet conditions for the sustainability of the rangelands