Influence of grazing management on vegetation,soil structure and nutrient distribution and the infiltration of applied rainfall in a semi-arid chenopod shrubland

The experiment utilized a fenceline contrast in vegetation and soil condition that was clearly visible on Landsat imagery. Measurements of vegetation cover, soil structure and chemistry, and infiltration were made. The greatest vegetation change was at the soil surface where the loss of litter and lichen crust cover under heavy grazing accompanied the loss of perennial shrubs. Although grazing caused changes in soil structure and chemistry to less than 10 cm in depth, these changes are quite significant for plant growth. Consistent differences in the infiltration of applied rainfall at two intensities were measured between the grazed and ungrazed sites. At both intensities of application the absence of a lichen crust increased infiltration three-fold on the heavily grazed site compared with the ungrazed site. The implications of these observations on the long-term functioning of this landscape are discussed.