Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/30/2010
Publication Date: 11/22/2010
Citation: Owens, L.B., Bonta, J.V., Shipitalo, M.J., Rogers, S. 2010. Effects of Winter Manure Application in Ohio on the Quality of Surface Runoff. Journal of Environmental Quality. 40(1):153-165. Interpretive Summary: Applying manure during the winter months is a common practice, especially among small to medium sized livestock operations with limited manure storage facilities. Manure applications during this time of year pose increased environmental risks. Soils which are saturated and/or frozen may have considerable surface runoff following rainfall or snowmelt. Such runoff can carry manure particles and nutrients to ponds and streams. Although winter manure application is not recommended, guidelines have been developed to minimize the detrimental aspects of this practice if it is necessary. Using the guidelines developed by the Ohio NRCS (Natural Resources Conservation Service), experiments were conducted at the North Appalachian Experimental Watershed near Coshocton, OH to evaluate the effectiveness of these recommendations. Liquid swine manure and turkey litter were applied at recommended rates to small watersheds (approximately 2 acres in area), which were in a no-till corn cropping practice. There was a 100 ft buffer area (no manure application) downslope from the area receiving manure. Beef slurry manure was also applied to grassed plots with either 100 or 200 ft grassed buffer. The highest concentrations of nutrients in runoff were measured when runoff occurred soon after manure application. However, most events with high concentrations occurred with low flow volumes, and therefore transport was minimal. Because of manure composition, applying manure at the N rate for crop needs resulted in P being applied at rates in excess of crop needs. This contributed to elevated P losses, which in turn contributed to a greater potential of detrimental impacts with P than with N. Nevertheless, if prescribed guidelines are followed, detrimental aspects of winter manure application can be reduced. These findings are important to producers, conservation groups, and regulatory agencies such as EPA.
Technical Abstract: Winter application of manure poses environmental risks. Six continuous corn, instrumented watersheds (approximately 1 ha each) at the USDA-ARS North Appalachian Experimental Watershed research station near Coshocton, Ohio were used to evaluate environmental impacts of applying manure to frozen soil. For 3 years on frozen, sometimes snow-covered, ground in January or February, two watersheds received turkey litter; two watersheds received liquid swine manure; and two watersheds were controls (received N fertilizer at planting, not manure). Manure was applied at an N rate for corn; the target level was 180 kg N ha-1. There was a 30m setback from the area of application to the bottom of each watershed. In addition, four grassed plots (61 x 12m) were used for beef slurry applications (9.1 Mg ha-1 wet weight); 2 plots had 61 x 12m grassed filter areas below them; 2 plots had 31 x 12m filter areas. There were 2 control plots, one for each of the 2 filter sizes. Ohio NRCS recommends a 61m buffer area for winter manure applications along with slope and vegetative cover recommendations. “Dustpan” runoff samplers were placed at the lower edge of each plot application area and 11m downslope; runoff was collected at the base of each filter area. Nutrient concentrations can be high, especially in runoff soon after application. However, most events with high concentrations occurred with low flow volumes, and therefore transport was minimal. During the first 2 years, runoff was above average and nutrient transport was elevated as a result. Because of manure composition, applying manure at the N rate for crop needs resulted in application of P in excess of crop needs. Elevated P losses contributed to a greater potential of detrimental environmental impacts with P than with N. Filter strips reduced nutrient concentrations and transport, but the data were too limited to compare the effectiveness of the 30m and 61m filter strips. Winter application of manure is not ideal, but by following prescribed guidelines, detrimental environmental impacts can be reduced.