Tuesday, November 14, 2006

Water Quality from Grass-Based Dairy Farm Tile Lines.

Lloyd Owens, USDA-ARS, PO Box 488, Coshocton, OH 43812

Subsurface water quality from agricultural systems varies with the type of system and management.  Systems with high inputs from fertilizer and/or manure may have nutrient levels, e.g. NO3-N, in subsurface water.  This study investigates the water quality from tile lines on grass-based dairy farms.  Monthly samples have been collected and analyzed from 1 to 4 tile lines on 7 grass-based dairy farms in eastern Ohio for more than 1 year.  A dry growing season in 2005 limited the number of available samples during that year.  Detailed management records often are not available, but preliminary data indicate that NO3-N and PO4-P concentrations in shallow groundwater from grass-based dairy farms are usually at acceptable environmental levels.  Nevertheless, if high rates of N fertilizer are applied, e.g. 280 kg ha-1 annually, NO3-N concentrations above 10 mg L-1 are measured.  Longer periods of study and data from more farms are needed to confirm the hypothesis that grass-based dairy farms have environmentally sound impacts on groundwater quality.

Handout (.pdf format, 114.0 kb)