Dormaar and Willms studied the components of the organic matter in soil under 3 mixed prairie types: grassland dominated by needle-and-thread/blue grama (Stipa comata/Bouteloua gracilis) in good range condition; grassland significantly modified by grazing, dominated by blue grama and in poor range condition; and grassland, dominated by needle-and-thread/blue grama in good range condition, but converted to cropland and under continuous wheat for 4 years. Soils in grazed pastures had less monosaccharides and more microbial carbohydrates than soils inside of grazing exclosures possibly because of reduced incorporation of plant material into the soil. Greater levels of organic acids in grazed pasture soils were most likely a result of allelopathic chemicals exuded by the plants present at the site. These results suggest that grazing can alter soil chemical characteristics and that recovery of a site after grazing is removed may be limited by allelopathic chemicals present in the soil.
Citations and enhanced abstracts for journals articles and documents focused on rangeland ecology and management. RSIS is a collaboration between Montana State University, University of Idaho, and University of Wyoming.