Submitted to: Wisconsin Forage Council Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 28, 1997
Publication Date: N/A
Technical Abstract: Are intensive grazing systems causing environmental problems in Wisconsin and surrounding states? The short answer is, 'We don't know,' but evidence from other countries and from a few studies in the USA suggest that contamination of water by nitrogen and phosphorus losses from pastures may be significant. The multiple benefits of intensive rotational grazing, including economic returns, higher quality of life for the farm family, improved herd health, and more diverse farm ecosystems, are strong incentives to expand the use of this management system. Nitrogen losses occur mainly as ammonia volatilization from urine spots, denitrification in wet soils, and nitrate leaching on coarse textured soils. We found little nitrate leaching loss on fine textured soils where dairy cows were grazed. Runoff losses of N generally are small from pastures, but P losses can be high. To minimize the chance of causing water pollution, graziers need to be aware of how feed supplementation, soil texture and slope, plant species, commercial fertilizer and manure addition, location of water tanks and shade, and other management variables affect urine and dung deposition.