The timing and amount of manure application to land is important in order to manage nutrients and to meet the regulatory requirements and guidelines developed by the South Dakota Department of Environment and Natural Resources and the Natural Resources Conservation Service as outlined in e.g. the conservation practice standard 590 on nutrient management.
Spreading manure on frozen ground is an important management option for livestock producers since winter spreading of manure reduces the quantity of winter storage needed, provides more time for application on cropland and reduces soil compaction by heavy equipment. Because of reduced infiltration capacity of the soil when frozen and manure being applied on snow, there is a risk of manure including fecal coliform bacteria, nutrients and suspended particles being carried off the field with water runoff. Fecal coliform bacteria, nutrients, and sediment have been identified as sources of water resource impairment in many South Dakota watersheds. There is a need, therefore, to balance the application of manure on frozen ground to impacts on surface water quality.
The overall project goal is to evaluate the environmental risk of spreading manure during winter conditions and develop BMPs for winter manure spreading that minimize water quality impacts. The goal will be attained by completing activities designed to reach four objectives:
- Assess the impact on surface water quality following spreading manure on frozen soils,
- Compare winter manure spreading practices related to location, timing and placement within a field to minimize water quality impacts and develop BMPs,
- Develop a climatic risk factor using frequency of soil frost and rainfall events, and
- Provide education on winter manure spreading BMPs to livestock producers, extension educators, and resource managers.
Video 1: This video shows the runoff amount from the main snow melt day we observed from one of three field sites (10 acres) during the winter 2011-2012.
Video 2: This video shows the runoff on May 5 2012 following a high intensity rain event (1.4 inches of rain in 20 mins).