Assessment of cattle impacts on soil characteristics in integrated crop-livestock systems

As population density rapidly increases and less land becomes available, an integrated crop-livestock system represents one of the key solutions for sustainable crop and livestock production in today's agricultural systems. However, much debate remains regarding how to best manage these systems to increase the productivity and economic returns while achieving objectives of environmental protection and mitigation of climate change. For instance, it is suggested that effective use of cattle manure can likely enhance the carbon sequestration processes in soils; however, it is unclear about the impacts of grazing cattle on soil characteristics. Our hypothesis is that livestock unevenly impact crop yields and GHG balances in integrated crop-livestock systems based on uneven field utilization while grazing. We have conducted a corn residue grazing experiment on the Dudley Smith Farm (Pana, Illinois) in 2011. The movement of six groups of heifers on corn residue fields were monitored via Global Positioning System (GPS) under two different grazing management practices: strip-grazing and continuous-grazing. Additionally, soil samples were taken before and after the grazing season. The preliminary results show that the corn residue fields were not evenly utilized by cattle, and strip grazing has significantly changed the pattern of cattle foraging and bedding behaviors compared to continuously grazing. The soil analysis results show that the total carbon and nitrogen in soils have a positive correlation, and that higher cattle visit density may have prevented the soils from losing carbon and nitrogen.