Rotational Grazing and Water Quality

By Steve Boyles

Maintaining forage cover and using it for pasture or hay production should meet conservation compliance demands. A diverse group of people representing the local cattle organization, feed store, auction facility, fence building business, veterinary clinic, and the soil and water conservation district cooperated on a grazing project. The primary objective was to observe nitrates levels in surface water run-off from grazed and ungrazed sites. This information could be used to evaluate if rotational grazing is compatible with surface water quality requirements.

An intensive rotational grazing project was initiated within the Indian Lake Water Shed.  The land was seeded to orchardgrass, timothy and red clover. The soil was a Napponee St. Clair silt/loam with 6-12% slopes which is typical of Logan County, Ohio. There were not any trees within or adjacent to the grazing site.

The 40 acre area was divided into four sections. Perimeter fence was high tensile fence (5 strands, 3 electrified) on wood posts. Internal fence separating sections was 1 strand of electric wire on wood posts. However, one section was completely enclosed with 5 strands of high tensile for an arrival area to acquaint cattle with electric fence. A total 28 grazing cells were created with movable electric tape on fiberglass posts so that each cell was 1.5 acre in size. Highway guard rail was used to make a 2-pen corral.

The cattle were moved daily at approximately 8 AM within the grazing site. Electric tape was placed in front of the cattle and behind the cattle to define the daily grazing cell. A third line of electric tape was placed ahead of the cattle to define the next grazing cell. The cattle rapidly learned to move to the next grazing cell when the fence was placed down in front of them.

Water and electricity was provided from a barnyard a short distance from the grazing site. Black, plastic pipe (1 inch internal diameter) was laid along the fence.  Connection sites were placed within the water line so that a portable water trough could be moved to the paddock that calves were currently grazing. Calves always had access to salt and mineral supplement in a portable feeder.

The Ohio Water Quality Standards (Ohio Administrative Code 3745-1-04) specify that all surface water of the state must be free from the following pollutants as a result of human activity: suspended solids, floating debris, color, odor, toxic substances and nutrients that create nuisance growths of aquatic weeds and algae. Longitudinally cut plastic barrels were placed in holes in the ground at natural drainage spots in proximity of the grazing site. Two plastic barrels (Site 1 and Site 2) were placed in the grazing project to collect surface water runoff for nitrate testing and one barrel (Site 3) was placed adjacent to the project area on CRP land and used as a control. Surface run-off samples were collected if there was a 1 inch or greater rainfall.

An area cattle feeder supplied the cattle each year. The cattle were fed on a contract basis.  Crossbred steers were grazed in year 1 and crossbred heifers were provided in years 2 and 3. There was a seasonal average stocking rate of 1.5 head per acre during the three-year study. All cattle went through a deworming protocol.  Cattle had free choice access to mineral supplements.  Based upon beginning and ending shrunk weights, average daily gain was 1.4-1.5 pounds per day.

RESULTS AND DISCUSSION

Ohio EPA must notify the area residents when water nitrate nitrogen levels are greater than 10 mg/kg. The average nitrate-nitrogen level was 3.5 ± 0.99 mg/kg. The average nitrate nitrogen level for the control site was 3.6 ± 1.51 mg/kg.  The current equipment would be relatively easy to remove and sell if there was a decision to return the land to crop production.  Managed intensive grazing land is compatible with maintaining surface water quality.

Boyles, S., B. Stoll &T. Dobbels. 2001. The Use of Conservation Reserve Program Land for Grazing Cattle.  J. Sust. Ag. 18:113-120.  https://www.tandfonline.com/doi/abs/10.1300/J064v18n04_10