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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #117746
Title: NRAES 135 PASTURE-BASED LIVESTOCK PRODUCTION - CHAPTER 8: ENVIRONMENTAL IMPACTS OF GRAZING

Author
item Stout, William
item CROPPER, J - NRCS
item Sharpley, Andrew
item Shelton, Daniel
item Owens, Lloyd
item SCHNABEL, R - DECEASED
item CLARK, E - UNIVERSITY OF GUELPH

Submitted to: Natural Resource Agriculture and Engineering Service
Publication Type: Book / Chapter
Publication Acceptance Date: 6/1/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Grazing is thought to be an inherently environmentally friendly practice. This chapter evaluates the environmental impacts of grazing on soil compaction, nutrient cycling, pathogen transport, riparian areas, and carbon dynamics. Soil texture, soil moisture content, and the type of animal grazing the pasture can affect compaction in pasture soils. Increased compaction can reduce pasture growth because it increases water runoff and decreases the water storage capacity of the soil. Nutrients, such as nitrogen and phosphorus, are concentrated in pastures in urine and fecal patches. This causes a large portion of nitrogen to be leached below the root zone and causes phosphorus to be more susceptible to loss through surface runoff. Livestock are susceptible to a variety of pathogens that are also toxic to humans. Transport of these pathogens from pastures depends on many interactive factors ranging from livestock excretion rates, ,to soil properties and watershed hydrology. Because of the complexity of these interactions, quantitative relationships regarding pathogen transport have yet to be established. Pastures often extend into riparian areas and uncontrolled grazing in riparian areas can increase sediment, nutrient, and pathogen load into the stream. Thus management of pasture riparian areas is critical in maintaining water quality. Grazing can have both positive and negative effects on soil organic carbon. Replacing cool-season grasses with warm-season grasses can increase soil organic carbon, but replacing endophyte infected tall fescue with endophyte free tall fescue will decrease it. However, the overall effect of grazing on soil organic carbon is largely unknown.