Energy Management at University Farms

Abstract. Energy is an input cost to agricultural production. Knowing typical values can help farmers to evaluate management options. Diesel, propane, and electrical energy used on the farm during selected field operations, crop drying, and in swine housing were measured on Iowa State University research and demonstration farms. Baseline values were measured and tractor operation management styles were compared.

Strategies for saving fuel were demonstrated in 30 of 35 tractor operation comparisons. Comparisons of gear/engine speed, tillage depth, travel speed, and use of front-wheel-assist averaged 29, 27, 15, and 14% more energy used than the fuel-saving alternative. Single drive wheels used 8% more energy than duals, but results were mixed when comparing different tire inflation pressures.

Energy used in high-temperature drying in bins ranged from 4.67 to 7.70 Mj/kg (2010 to 3310 Btu/lb). Most energy was used from propane (96%). Propane use averaged 0.0027 L/kg (0.018 gal/bu) per percentage point of moisture removed.

Minimum ventilation fans had the highest duty factor in a curtain-sided swine finishing barn. Electrical use was greater in tunnel-ventilated than curtain-sided barns (29.0 vs. 20.9 kWh/pig space-yr) and propane use was greater in wean-to-finish than finish-only operations(10.6 L vs. 2.5 L/pig space-yr, 2.8 gal vs. 0.67 gal/pig space-yr).