Submitted to: Agronomy Abstracts
Publication Type: Abstract only
Publication Acceptance Date: 8/1/1997
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Does increasing use of management intensive grazing on dairies in the Upper Midwest USA increase the potential for NO3 leaching losses? We determined NO3 lost under grazing versus mown systems, and whether dietary supplementation decreased NO3 losses by improving the conversion of feed N to milk N. In grazing experiments with lactating dairy cows on silt loam soils in south central WI and western MN, we monitored milk production, soil NO3 concentration, and NO3 losses. Dietary supplementation increased milk yield in two site years but not in a third. Nitrate leaching was insignificant in all cases, even directly under urine patches. With good animal and fertilizer management on these deep, fine-textured soils, NO3 leaching losses probably are minimal for midwestern pastures dominated by deeply rooted perennial species, and supplemental feed appears to be profitable.