Matt Smith and Dr. John Aber

1. Reducing energy requirements and closing the carbon and nitrogen cycles at the UNH Organic Dairy Research Farm through on-farm bedding production and aerobic static pile composting Matt Smith and Dr. John Aber Project Summary Phase 3: Use Shavings for the Farm Bedded-Packs Phase 5: Heat Recovery from Compost • Project Goal: A more closed agroecosystem • Reduced carbon and nitrogen footprints • Produce bedding from farm woodlots • Eliminate long-distance delivery • Sell shavings to other UNH research farms • Improved manure management • Aerobic static pile (ASP) composting with thermal energy capture • Eliminate odors and methane emissions • Reduce volume of material to be spread on farm fields, saving fuel and transport costs • Produce more stable product less prone to leaching • Use wood shavings on the three bedded-packs and in the calf hutches • Bedded-packs top-dressed twice a week with bedding, and cleaned out twice a year (May and October) • Heat is produced from microbes under an aerobic composting environment • Microbes receive oxygen through a fan system that pulls oxygen through the pile, while pulling heated compost vapor out of the pile • Heated vapor (130-160oF) is sent into Agrilab’s Compost Heat Recovery Systemtowarm a 295 gallon tank of water to 100-120oF for farm hot water needs • Research Note: Trials on heat production/capture through manipulation of aeration, irrigation, nutrient addition, and compost covers, are underway. Economics of the entire heat-recovery system are ongoing Phase 4: Compost Farm Wastes in the ASP Facility • Used bedded-pack, manure, hay, and woodchips, are combined in a specific “compost recipe” and loaded into the ASP composting facility with a manure spreader • Current recipe: 4 yd3 used bedded pack, 2 yd3 manure, 2 yd3 hay, and 2 yd3 woodchips per 10 yd3 batch, with 20-25 batches per bay (200-250 yd3 per bay per month) • Research Note: Trials on optimal compost recipes for heat production are capture are underway Phase 1: Harvest Trees for Bedding • Annual harvest of 1-2 acres from 160 acre farm woodlot • Yields 60 cords of eastern white pine/year • Equals the farm’s annual bedding requirement of 700 yd3 of shavings Phase 6: Compost is Spread on Farm Hayfields • Compost spread following 90-120 days in the ASP facility • Compost may be sold in the future to reduce farm N and P footprints and also generate revenue for future research Phase 2: Produce Animal Bedding • Shave 8 ft eastern white pine logs with a wood-shaving machine • Machine produces 12-20 yd3 of wood shavings/hour • Only softwoods are suitable for bedding - contain resins toxic to disease-causing microbes (Godden et al. 2008). Also easier to shave. Phase 7: Future Work Reducing C and N Footprints C-footprint reductions from CO2 scrubbing of the compost exhaust stream by plants in a high tunnel attached to the composting facility. N-footprint reductions from NH3 and N2O scrubbing of the compost exhaust stream from a woodchip/compost biofilter attached to the composting facility. Research Note: Trials comparing eastern white pine v. eastern hemlock as bedding source are underway. The economics of an on-farm bedding production operation are also being analyzed. References Project Supported By: Contact Godden, S., Bey, R., Lorch, K., Farnsworth, R., and Rapnicki, P. 2008. Ability of organic and inorganic bedding materials to promote growth of environmental bacteria. J. Dairy Sci.,9, 151-159. Smith, M. and Aber, J. 2014. Heat recovery from compost. BioCycle, 55(2), 27. Matt Smith University of New Hampshire ms7@wildcats.unh.edu Aberlab.net 603-285-5197