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:
This is the final report for the project 8070-21000-008-00D which terminated in November 2017. All planned experiments were completed with the exception of the miscanthus study (Sub-objective 1.B.1) which will be completed under the current bridge project (8070-21000-009-00D). In addition, other accomplishments covered under the bridge project will be extensions of the sub-objectives outlined in this project plan. A new project plan is currently undergoing OSQR review that is built heavily upon the results of these two project plans. Over the 5 years of the project, significant progress was made on all three objectives. Under Objective 1, research produced and improved fundamental knowledge of how changes in climate affected forage distribution which in turn impacted grazing behavior of dairy cows. Management practices were assessed and developed on how to mitigate these effects, including supplementation strategies for dairy cows as well as crop rotations, soil characteristics and micro-climates. Research is continuing under the 1-year bridge project as well as in the new proposed 5-year plan to better understand the interactions among forage and animals, and now includes soils and cropping systems. One significant result of this research was an invention disclosure for an improved system to monitor grazing behavior and location in dairy cattle. A patent was submitted for this invention under the bridge project. Also under Objective 1 ARS scientists and collaborators at the University of Minnesota found that fodder systems may be a very costly method of producing feed for dairy producers where high-quality forage production is possible. However, these systems may have application in small-scale operations, farms with high lands values where tillable acreage can produce high-value crops, farms with excess labor, or for producers experiencing severe extended drought. Each farm must put pencil to paper to determine if fodder is economical, or if money could be better spent growing or purchasing higher-quality forage. Also under Objective 1, annual forages can be used to ‘fill gaps’ when other perennial pasture forages are not as productive, such as mid-summer and late fall. Strategic use of annual forages in livestock production has the opportunity to increase body weight gain of grazing ruminants compared to traditional perennial forage systems. Moreover, combining annual grazing systems with row cropping systems decreases both economic and environmental risk associated with the intensification and specialization of modern agriculture. However, more research is needed not only in individual seasonal systems, but also in year-round, integrated-crop livestock systems in order to determine possible economic and environmental benefits of such systems. Under Objective 2, ARS scientists evaluated greenhouse gas (GHG) emissions of cropping strategies that included warm-season forages harvested for biomass production and developed recommendations for research, advisory and regulatory groups to develop cost-effective GHG mitigation strategies for biomass production. This work will continue under the 1-year bridge project. Also under Objective 2, ARS scientists in University Park, PA and university scientists evaluated a farm level framework to reduce uncertainty in estimating N2O to increase adoption of low GHG emission practices. We found that this framework was effective at reducing the uncertainty of N2O estimation and could provide significant incentives at the farm for adoption of low GHG emission practices. Incorporation of this framework could increase the adoption of mitigation strategies which reduce N2O emissions associated with crop production. The third objective, which was added in FY2014, is related to national ARS efforts on economic and environmental sustainability of dairy farms, including GRACEnet, the Long Term Agroecosystem Research (LTAR), the Dairy Agroecosystem Working Group (DAWG), the Conservation Effects Assessment Project (CEAP), the Dairy Grand Challenge, and the Climate Hub. These national initiatives have become an integral component of the research conducted at the USDA-ARS Pasture Systems and Watershed Management Research Unit. Location scientists have taken leadership roles in these initiatives which have resulted in regional and national collaborations and expanded research objectives. Additionally, the third objective of this project plan was the focus of the new project plan that focuses on the impact of the integration of crops, pastures, livestock and soil on soil and water quality which are broad goals and objectives of these national initiatives. Another item Forage brassicas are cool-season annual forages that can be used to fill 'forage gaps' when other pastures are not as productive, such as mid-summer and late fall. ARS scientists supplemented either one of three forage brassicas (canola, rapeseed, and turnip) or annual ryegrass to a perennial cool-season pasture (orchardgrass) to evaluate the effects of these forages on ruminal fermentation and methane production in a continuous culture fermentor system. Use of brassicas in a ruminant grazing system could extend the fall grazing season and reduce winter feed costs while increasing animal efficiency and decreasing enteric greenhouse gas emissions. Additional research is needed with grazing animals to evaluate the long-term effects of grazing brassicas on animal health, production efficiency, and greenhouse gas output.
1. Field location affects greenhouse gas emission. Field specific factors affect sustainability. Greenhouse gas (GHG) emissions associated with crop production vary from farm to farm. ARS scientists in University Park, Pennsylvania, and university scientists evaluated the cost and change in GHG emissions from use of different farm management practices with switchgrass production. We found that soil characteristics along with previous crop history, management practices, and distance to market all affected the combination of practices delivering the lowest cost GHG mitigation. This finding will inform university, industry, and government agencies of the importance of location specific factors in developing the most cost-effective GHG mitigation strategies.
3. Molasses can replace corn in grazing dairy cow diets. Grazing dairy farms are interested in replacing corn supplement with molasses to decrease feed costs and meet the goals of specialty milk markets such as organic or grassfed milk. We investigated the effects of supplementing grazing, lactating dairy cows with either corn meal or liquid molasses on milk yield and milk composition, milk fatty acid profile, and nitrogen use efficiency. Based on results of the current experiment, molasses can replace corn meal on an equivalent basis without negatively affecting milk yield and composition, while slightly improving N (nitrogen) efficiency and beneficial fatty acids found in milk.
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