Sustainability and Efficiency of Dairy Production Is Affected By Crops.

Animal agriculture is challenged with societal issues such as animal welfare, antibiotic use, food vs feed, nutritional needs of humans for animal protein, and sustainability. Some of these issues can be emotional and accurate information is required to engage on these topics. Agriculture, both crop and animal ag, is considered a major contributor to greenhouse gases (GHG); however, agriculture can be a solution for storing GHG. Cropping systems are major decisions for dairy farms and most farms in the US rely in large part on genetically modified (GM) crops. In the US, more than 90% of corn, soybean and cotton are GM and animals are a major consumer of these crops. Current benefits of GM crops are from input traits, such as herbicide tolerance and insect resistance. Even though trusted organizations, like the National Academies of Sciences, have concluded that GM foods are as safe as conventional foods, consumers don’t always perceive the value of these traits. This has affected consumer acceptance of GM technology as well as how meat, milk and eggs are produced. To better understand the ecosystem impacts associated with various management practices applied to both GM and conventional hybrid corn and soybean cropping systems, a model-based analysis was performed across 12 states in the U.S. corn-belt. The analysis generated potential erosion and GHG emissions estimates associated with the implementation of several practices based on public SSURGO data, NASS crop productivity data, and spatially explicit weather data. Rill and inter-rill erosion resulting from rainfall and surface runoff were modeled and sediment loss and deposition due to wind was simulated. In addition to erosion, soil organic carbon (SOC) change and nitrous oxide flux (N₂O) were modeled using the Denitrification-Decomposition model (DNDC). Based on the analysis, average GHG emissions associated with corn production across the 12-state region could be reduced by an estimated 8.7 kg CO₂e/bu and 14.3 kg CO₂e/bu by switching from conventional hybrid production to a reduced till and no-till GMO system, respectively. A corresponding average reductions in soil loss of 10.9tn/ac and 13.6 tn/ac due to water and wind erosion were also estimated based on a change to a reduced till or no-till GMO system. Based on the model estimates, feeding GM crops makes production of meat, milk and eggs more sustainable with respect to GHG emissions and erosion.