ABSTRACT:
Stocking rate is the key, determining effect of management intensive grazing on dairy farm profitability. However, increased stocking rate can increase NO3 leaching from pastures. Increasing stocking rate increases NO3- loss through leaching because the bulk of the N conszdmed by the anilmal is excreted in concentrated areas of the pasture mainly in urine. We used experimental data from the northeast U.S. and the literature to assess the relationships between stocking rate and NO3 leaching losses beneath an intensively grazed pasture. A relatively low cumulative seasonal stocking rate of about 200 mature Hothead ha−1 could result in a 10 mg l−1 NO3N concentration in the leachate beneath a fertilized, intensively grazed pasture. This means that while management intensive grazing can improve farm profitability and help control erosion, it can have a significant negative effect on water quality beneath pastures. The extent to which this effect occurs within specific watershed need to be evaluated in context of the other cropping systems and lands uses within the watershed.
Footnotes
W.L. Stout is Soil Scientist for the U.S. Department of Agriculture, Agricultural Research Service (USDA-ARS), Pasture Systems and Watershed Management Research Laboratory (PSWMRL). S.L. Fales is Professor and Head of the Department of Agronomy, The Pennsylvania State University. L.D. Muller is Professor of Dairy Science, The Pennsylvania State University. R.R. Schnabel is Soil Scientist, USDA-ARS-PSWMRL. G.F. Elwinger is Support Scientist at the USDA-ARS-PSWMRL. S.A. Weaver is a Soil Scientist at the USDA-ARS-PSWMRL.
- Copyright 2000 by the Soil and Water Conservation Society
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