Farm simulation: a tool for evaluating the mitigation of greenhouse gas emissions and the adaptation of dairy production to climate change

Authors: Rotz, Clarence - Al; Skinner, Robert; STONER, ANNE - Texas Tech University; HAYHOE, KATHARINE - Texas Tech University

Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Abstract Only
Publication Acceptance Date: 1/14/2015
Publication Date: 5/3/2015
Citation: Rotz, C.A., Skinner, R.H., Stoner, A.M., Hayhoe, K. 2015. Farm simulation: a tool for evaluating the mitigation of greenhouse gas emissions and the adaptation of dairy production to climate change. Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE). Available at: http://elibrary.asabe.org/azdez.asp?AID=45511&T=2.

Interpretive Summary:

Technical Abstract: Process-level modeling at the farm scale provides a tool for evaluating both strategies for mitigating greenhouse gas emissions and strategies for adapting to climate change. The Integrated Farm System Model (IFSM) simulates representative crop, beef or dairy farms over many years of weather to predict performance, economics and environmental impacts. This includes various gas emissions and a farm-gate life cycle assessment of carbon, energy, water and reactive nitrogen footprints of the feed, meat or milk produced. The IFSM was used to simulate a representative dairy farm in New York over 25 years of recent historical weather to determine the environmental benefits and economic costs of alternative manure handling strategies. Use of a bottom-loaded manure storage tank increased nitrous oxide emissions, but reduced methane emissions, providing a 4% net decrease in the farm-gate carbon footprint of the milk produced. Use of an unsealed cover reduced the carbon footprint by 12% with a $4/cow reduction in profit. An 18% reduction in the carbon footprint was attained at a net cost of $20/cow using an enclosed tank with a flare to burn any methane produced. Using an anaerobic digester to produce gas and electricity on the farm reduced the carbon footprint by 16% and reduced profitability by $25/cow. Climate change is projected to affect many aspects of dairy production including growing season length, crop growth processes, harvest timing and losses, cattle performance, nutrient emissions and losses, and ultimately farm profitability. Climate projections for higher and lower emission scenarios were downscaled from the Community Climate System Model version 4 (CCSM4). IFSM was then used to simulate the same New York dairy farm over 25 year periods using recent historical weather and projected middle and end-of-century climate. We adapted the farm to future climate by modifying crop varieties and planting and harvest dates. Warmer temperatures increased volatile loss of ammonia N, and changes in precipitation patterns increased nutrient runoff losses. Nitrogen leaching losses were inconsistent with some climate scenarios showing increases and others showing decreases. The reactive N footprint of the milk produced was increased by 10-15% with the change in climate, but other environmental footprints were relatively unaffected. Farm profitability increased by up to $50/cow per year for some climate scenarios, but for the high end-of-century projection, annual farm profit decreased by $40/cow. The projected change in climate increased the risk or annual variance in profit reflecting greater annual variation in crop and animal productivity.