In a recent study, applying hog manure to pasture grass increased crude protein by 80% and brought a three-fold increase in yield. University of Manitoba researchers applied enough manure to achieve an annual application rate of 110 lbs/acre of available nitrogen. The fate of manure nutrients was monitored by extensive measurements of soil, groundwater and pasture forage. Although the amount of phosphorus added exceeded the crop’s ability to take it up, the surpluses remained in the root zone. Similarly, there was no evidence that significant quantities of nitrate moved into the groundwater.
Salmonella and E.coli were present in hog manure, but concentrations in soil and forage were low, and there was no evidence that they were transferred to grazing cattle.
The researchers concluded that applying hog manure to grasslands is an environmentally responsible pasture management and nutrient recycling practice. They hope their findings will help to improve the economic and environmental sustainability of Manitoba’s livestock industry. Their work was partially funded by a grant from the Manitoba Livestock Manure Management Initiative.
The full report, entitled “Best Management Practices to Improve the Productivity and Environmental Sustainability of Grassland Pasture Systems,” is available on the Manure Initiative’s Web site at www.manure.mb.ca.