Long-term Grazing Effects on Stripa-Bouteloua Prairie Soils

Abstract

The effects of grazing on Stipa-Bouteloua prairie soils in Alberta were evaluated after 19 years of continuous summer use by sheep at three stocking intensities. Analysis of the soils under the heavy grazing treatment showed lower values for pH and percent spring moisture but higher values for total carbon (C), alcohol/benzene-extractable C, alkaline-soluble C, polysaccharides, and belowground plant material than the soil under light or no grazing. The results were attributed to changes in amounts and kinds of roots due to species changes caused by grazing and to increased amounts of manure deposited by sheep on fields grazed at a higher intensity. Shallow-rooted species replaced the deeper-rooted ones on the drier environment induced by heavy grazing.