1a. Objectives (from AD-416):
1: Identify, through experimentation and plant growth and habitat modeling, pasture-based dairy and livestock production systems and management practices that improve food security by enhancing productivity, improving long-term environmental sustainability, and increasing flexibility to adapt to changing environmental and climatic conditions. We will initially delineate current land-use practices for grazing lands in the eastern US and investigate how land use might change in the future (sub-objective 1.A). Primary land use practices to be considered are pasture-based animal agriculture and bioenergy feedstock production systems. Sub-objective 1B will characterize potential changes in forage species distribution and dairy cow grazing behavior in response to climate change (adaptation), and evaluate plant and animal management strategies to mitigate climate change. Sub-objective 1.C will identify conservation practices and animal management strategies that improve nutrient utilization efficiency and reduce sediment and nutrients movement off-farm. 2: Develop best management practices and identify management systems that improve productivity and environmental sustainability of bioenergy production as part of multifunctional agricultural systems. Objective 2 focuses on bioenergy cropping systems and will identify management systems that increase soil C sequestration and reduce N loss and net GHG emissions (sub-objective 2.A) and evaluate the effects of miscanthus production at the commercial scale on C sequestration and GHG intensity (sub-objective 2.B). Sub-objective 2B will also include a life-cycle inventory assessment to profile the energy and GHG emissions associated with miscanthus production. Objective 3. Improve dairy industry production capacity and environmental sustainability to meet the demands of existing and emerging markets, and improve dairy industry resilience to abiotic and biotic stressors while maintaining producer economic viability. Using a comprehensive, systems approach along with existing/new databases and models to identify opportunities and support Livestock GRACEnet, LTAR and Climate Hub efforts to improve the environmental performance of dairy systems across the Northeast, Midwest, and West. The following research focus areas will be prioritized: a) Improve nutrient use efficiency across dairy production, emphasizing the conservation of nitrogen and phosphorus in local and regional crop production and reduction of off-farm nitrogen and phosphorus losses, especially through novel/greater use of forage crops and innovative practices. b) Improve carbon sequestration and reduce greenhouse gas emissions from dairy cattle, production facilities and land application of manure. c) Improve the understanding of pathogen transport and control through water and/or bioaerosol pathways.
1b. Approach (from AD-416):
This research will provide the necessary information for developing decision-support tools that bring together diverse forage production systems, innovative animal management strategies and novel biofuel production practices to build multifunctional farms and landscapes. The purpose is to provide guidance on optimizing the placement and management of pasture and bioenergy crops in ways that are appropriate to the landscape context and that will increase productivity and enhance ecosystem services of farming enterprises. We will initially delineate current land-use practices for grazing lands in the eastern US and investigate the production and environmental consequences of potential future management changes. Primary land-use practices to be considered are pasture-based animal agriculture and bioenergy feedstock production systems. We will provide information on plant and animal adaptation to climate change and on the effectiveness of greenhouse gas (GHG) mitigation strategies for grazing animals, pasturelands, and biofuel feedstock production systems. We will provide farm scale life cycle inventory (LCI) data on miscanthus and identify water quality and GHG impacts of switchgrass and miscanthus production on marginal lands We will also assess the effects of grazing management and manure application strategies on nutrient movement and water quality as part of the pasture component of the national Grazing Lands Conservation Effects Assessment Project (CEAP). Results will fill gaps in our knowledge of management practices that increase resilience to climate change, improve conservation of soil and water resources, and reduce GHG emissions. Successful completion of this project will 1) increase farm productivity, 2) improve adaptation to climate change and 3) provide targeted conservation practices to enhance ecosystem services.
3. Progress Report:
1.A.1. A landscape classification based on climate, soils and topography has been created for the entire continental United States, not just the Northeast as stated in the milestone. This classification has been cross-validated with the National Land Cover Dataset and with the Cropland Data Layer to develop probability estimates for pasture and other agricultural uses. 1.A.2. An optimization model of potential dairy production based on county-scale agricultural production options has been developed for the northeastern United States and is being used to characterize alternative land use scenarios. Biofuel species models have not yet been completed, although data collection and model development are in progress. 1.B.1. Topoclimatic models for common forage species in the northeastern United States have been completed. These species distribution models are being used with climate change predictions for four different emissions scenarios to develop future species range and abundance maps; these maps will be completed during FY2015. 1.B.2. Supplementing grazing dairy cows with kelp did not mitigate heat stress or improve milk production, but did increase milk iodine levels, which may be of concern to human health. Manuscript published in J. Dairy Sci (Antaya et al., 2015). 1.B.3. The initial GRACEnet cropping system experiment was concluded a year early and new treatments started adding cover crops to the existing corn-soybean-alfalfa rotation and comparing that system with a corn-soybean rotation. The perennial grasses switchgrass and reed canarygrass were harvested in August, November, and April, collecting biomass yield data; other management practices were completed as appropriate during growing season. New treatments were initiated on the grazed pastures comparing traditional rotational grazing with ultra-high density (mob) grazing. 1.B.4. Two manuscripts were accepted for publication in the J. Dairy Sci. (citations below). In the first study (Brito et al., 2015), molasses supplementation improved nitrogen utilization in grazing dairy cows, but flaxseed improved beneficial milk fatty acid profiles and enterolactone, a mammalian lignin with potential human-health benefits. In the second study (Resende et al., in press), supplementing flaxseed to lactating dairy cows fed high-forage diets improved beneficial milk fatty acid profiles of milk but decreased feed intake and milk production. A continuous culture fermenter study that evaluated the effects of alternative forages on ruminal fermentation and methane output of a pasture-based diet is currently being prepared for submission to J. Dairy Sci. 1.C.1. Supplementing a pasture or haylage-based diet with sprouted barley fodder marginally increased nutrient digestibility but resulted in a net loss of dry matter and energy available to feed when compared with the barley used to sprout the fodder. 1 manuscript (Hafla et al., 2014) accepted for publication in J. Dairy Sci. A second manuscript is in preparation for submission to J. Dairy Sci. to assess the effects of flaxseed supplementation on animal productivity and milk fatty acid profiles of grazing lactating dairy cows. 1.C.2. Manure and mineral fertilizer was applied in early-spring and after the first cutting at Rock Springs. Injection greatly increased N2O emissions and reduced first cutting yield compared with broadcast application or mineral fertilizer, but increased second cutting yield. Runoff samples are being collected for water quality analysis. Wet soils prevented manure applications at the second, wetter site. 1.C.3. Due to additional funding, data collection was extended for an additional grazing season. A third year of data collection for three grazing management strategies (continuous, rotational, and mob grazing) was completed. Progress is monitored through periodic site visits, conference calls, and emails with the university collaborator. 2.A.1. Water quality and soil N2O emissions data were collected regularly at the Mattern watershed. Biomass yield was determined at the end of the growing season. 2.A.2. Biomass yield data were collected and life cycle assessment was initiated. Controlled environment studies were conducted to evaluate biochar x soil effects on N2O emissions. 2.B.2. Fuel use was measured during miscanthus harvest.
1. Reducing the carbon footprint of cellulosic ethanol. After producing ethanol from crop residues such as corn stover and straw, a slowly decomposing byproduct remains which is typically burned for energy recovery, but harvesting crop residues can result in decreased crop yields and soil carbon levels. Agricultural Research Service (ARS) scientists in University Park, Pennsylvania, in collaboration with Drexel University and Colorado State University scientists compared the current practice of burning this residue, to applying it back to the land. They found that although most studies have recommended burning this material to generate electricity for the biorefinery, applying it to the land instead resulted in ethanol production systems with the lowest greenhouse gas (GHG) footprint, highest levels of soil carbon, and the greatest offset of GHG emissions. This finding could help the industry evaluate the different markets for byproducts produced at the biorefinery, considering both the economic and environmental impacts.
Antaya, N.T., Soder, K.J., Kraft, J., Whitehouse, N.L., Guindon, N.E., Erickson, P.S., Conroy, A., Brito, A.F. 2014. Incremental amounts of Ascophyllum nodosum meal do not improve animal performance but increase milk iodine output in early lactation dairy cows fed high-forage diets. Journal of Dairy Science. 98:1991-2004.
Adler, P.R., Rau, B.M., Roth, G.W. 2015. Sustainability of corn stover harvest strategies in Pennsylvania. BioEnergy Research. DOI:10.1007/s12155-015-9593-2.
Ogle, S.M., McCarl, B.A., Baker, J., Del Grosso, S.J., Adler, P.R., Paustian, K., Parton, W.J. 2015. Managing the nitrogen cycle to reduce greenhouse gas emissions from crop production and biofuel expansion. Mitigation and Adaptation Strategies for Global Change. DOI 10.1007/s11027-015-9645-0.
Adler, P.R., Mitchell, J.G., Pourhashem, G., Spataria, S., Del Grosso, S.J., Parton, W.J. 2015. Integrating biorefinery and farm biogeochemical cycles offsets fossil energy and mitigates soil carbon losses. Ecological Applications. 25(4):1142-1156.
Brito, A.F., Petit, H.V., Pepeira, A.B., Soder, K.J., Ross, S. 2014. Interactions of corn meal or molasses with a soybean-sunflower meal mix or flaxseed meal on production, milk fatty acids composition, and nutrient utilization in dairy cows fed grass hay-based diets. Journal of Dairy Science. 98:443-457.
Orr, A.N., Soder, K.J., Brito, A., Rubano, M.D., Dell, C.J. 2014. Effect of sprouted barley grain supplementation of an herbage-based or haylage-based diet on ruminal fermentation and methane output in continuous culture. Journal of Animal Science. 97:7856-7869.
Skinner, R.H., Dell, C.J. 2014. Comparing pasture c sequestration estimates from eddy covariance and soil cores. Agriculture, Ecosystems and Environment. 199:52-57.
Dorich, C.C., Varner, R.K., Pereira, A.B., Martineau, R., Soder, K.J., Brito, A.F. 2015. Use of a portable, automated, open-circuit gas quantification system and the sulfur hexafluoride tracer technique for measuring enteric methane emissions in Holstein cows fed ad libitum or restricted. Journal of Dairy Science. 98(4):2676–2681.
Sheehan, J., Adler, P.R., Del Grosso, S.J., Easter, M., Parton, W., Paustian, K., Williams, S. 2014. CO2 emissions from crop residue-derived biofuels. [Letter to the Editor]. Nature Climate Change. 4:932–933. doi:10.1038/nclimate2403.