Performing Department
Biological Systems Engineering
Non Technical Summary
Organic systems have developed value based on improved sustainability. The organic dairy industry has sustained growth representing a significant portion of all US organic investments. For stakeholders to make informed decisions that impact industry growth, there is need for assessment and quantification of the environmental footprint of organic dairy systems. This project proposes to develop eight life cycle assessment regional models for organic dairy systems in the US. Outputs will provide baseline farm level environmental impact data on global warming potential (greenhouse gas emissions), eutrophication potential (nutrient losses), ammonia emissions, and resource depletion (energy, water, and land use) for numerous farm types across the eight regions. Models will be used to evaluate potential mitigation strategies to inform stakeholders of practices with high environmental mitigation potential and recommend those strategies for targeted outcomes (i.e., emissions reductions strategies). Researchers will also explore critical modeling assumptions that significantly impact environmental outcomes of organic dairy systems including selection of enteric methane predictive equations, allocation strategies, and methods used to quantify the global warming potential of methane. The outcomes from this objective will allow researchers making recommendations for methodological standardization and improved comparisons between studies. Project output will be used to inform stakeholders of pathways to improve environmental sustainability through extension and outreach channels as well as a critical relationship with Organic Valley. This work addresses priority two of the Organic Transition program by developing models to document ecosystems services from organic dairy with emphasis on climate change mitigation pathways of integrated livestock-cropping systems.
Animal Health Component
85%
Research Effort Categories
Basic
10%
Applied
85%
Developmental
5%
Goals / Objectives
This work aims to build upon an existing farm scale LCA model for organic dairies to evaluate sustainability metrics that can be used to guide on-farm practice implementation targeting reductions in environmental impacts related to global warming potential (greenhouse gas emissions and carbon sequestration), ammonia emissions, resource depletion (energy, land, and water use), and eutrophication (nutrient losses).Specific objectives include:Expand existing regional LCA models of organic dairy farms to cover the continental US for the environmental impacts of global warming potential (greenhouse gas emission and carbon sequestration), ammonia emissions, resource depletion (energy, land, and water use), and eutrophication (nutrient losses). Currently models have been developed for the Midwest/Great Lakes, New England, California, and Pacific Northwest regions. This work aims to develop additional regional LCA models using the developed framework for the Northeast, Mideast, Southwest, and Mountain regions to ensure all locations in the continental US have representative models to provide environmental impact data for all representative organic dairy systems.Assess environmental impacts of specific management practices in all US regions using the developed LCA modeling tools. This includes the identification and development of key variables that may be different for organic farms than previously modeled conventional farms (e.g., feed efficiency, replacement rate, diet composition) not currently available in the literature.Evaluate LCA methods to quantify environmental impact estimations, specifically enteric methane predictive equations, nitrous oxide emission factors from manure in pastures, allocation strategies, and methodologies for calculating the global warming potential of methane as they are important to the total estimations for greenhouse gas emissions from organic dairy farms.Develop extension materials and coordinate outreach activities. This includes developing fact sheets and other materials for each region. Researchers will also work with industry stakeholders to increase practice implementation and therefore environmental outcomes.
Project Methods
The proposed methods are detailed by objective below. Each objective includes the relevant scientific procedures, preliminary data, stakeholder engagement, and expected outcomes.Objective 1:LCA models were developed specifically for organic dairy systems at the University of Wisconsin-Madison by co-PI Aguirre-Villegas with the input from Organic Valley, a Cooperative of organic dairy producers and other university researchers. The US was divided into eight representative regions based on farm design and management practices using survey data and regional climate data. Regional models were developed to capture the effects of regionally specific environmental conditions and representative farm types and practices. To estimate these regional effects, data on environmental conditions, such as temperature and precipitation (collected from the National Oceanic and Atmospheric Administration), emissions from the electric grid (from the US Energy Information Administration) and energy matrix (from the US Department of Energy), crop yields and irrigation (from USDA-NASS national surveys), are collected from each state and averaged for each region based on the number of farms/milk production on each state. It is important to capture these differences as they are directly related to environmental impacts.In addition, it is important to evaluate the different practices adopted by the farm as they interact with environmental conditions. It is also common for many farms to select management and farm designs that fit their specific needs, and these practices are generally common to a region. This division allows for more accurate representation of organic dairy environmental impacts across the US.Each regional model tracks a variety of inputs through the system and allocates them to outputs that include milk, meat, and emissions (or losses) to the environment. The system boundaries for the LCA include all processing steps needed to produce milk on the farm. For this LCA, the functional unit is 1 kg (2.2 pounds) of fat and protein corrected milk (FPCM), adjusted to 4% fat and 3.3% protein. In each region, farm published data, survey data, expert and stakeholder opinion can be used to identify the most common practices for modeling purposes. Each location identified then requires detailed data collection for all model inputs needed to produce milk (starting from the extraction of natural resources to produce all energy and material inputs used by the farm until milk is produced at the farm gate). Inputs used by organic farms to be included in this assessment are water, energy (gasoline, propane, natural gas, fuel oil, diesel, and electricity) and materials (fertilizers, feed supplements, seeds, bedding, etc.). After identifying these inputs, inventory data is developed based on how much of each input is consumed at each farm layout and the emissions resulting from producing and consuming those inputs at the farm.Emission data from energy and materials will be generated with the SimaPro LCA Software (Pre-Consultants bv 2019). Biotic emissions, from the animals and manure management, are estimated with a series of process-based models and emission factors that relate management practices with environmental factors and physical characteristics of each system. A similar approach will be used to assess additional environmental impact categories for all regions and farm systems designs including resource depletion (including fossil energy, water use, and land use), and eutrophication potential. Besides emission sources, there are emission sinks in the form of carbon sequestration at organic farms as they rely mostly on grazing and forages for cow feed.For this project, the developed regional models using the detailed methodologies above will be expanded to cover all regions of the US, and the regional models further expanded to include additional functional units. This development will allow for environmental assessment of all regions in the US with organic dairy production.Objective 2.Farm management practices are the critical components of the system that producers can control to mitigate their environmental impacts. Using the models developed the environmental impacts of alternative management practices will be explored to determine their mitigation potential in all impact categories. These changes will be modeled to identify practices with the greatest mitigation potential with respect to the baseline environmental impacts developed in objective 1and to evaluate if there are any trade-offs between environmental impact categories.This information can be used to guide design or management changes to achieve specific environmental outcomes and allow for quantification of those outcomes and to develop and track progress for mitigation targets.Objective 3.Among some of the most important of these decisions are the selection of models to predict enteric methane emissions, the allocation strategies used to partition environmental impacts between milk and meat, the selection of models or factors predicting nitrous oxide emissions from manure excreted on pastures, and more recently, the methods for quantifying the global warming potential of methane. For this study:In this work we propose to evaluate a variety of enteric methane predictive equations to determine the range of outcomes and the data requirements and interpretative ability to inform users of farm level interventions.This study will conduct a thorough literature review on nitrous oxide emissions from manure deposited on pastures and model alternative factors to the one suggested by the IPCC based on literature findings. The range of emission factors will be documented, logical bounds applied based on expert opinion, and the impact of this range provided using a sensitivity analysis. The results of this work will be able to provide insight of the importance of this variable and importance of further field research if needed.This study will apply different allocation strategies and clearly detail the methods used to assign the environmental impacts between milk and meat. It is important to analyze these different methods for transparency purposes and to facilitate the replication of the study and comparison to other studies evaluating the impacts of dairy systems. It is also important to show how results can vary based on these decisions, as the results from these types of studies might serve as the basis for local or regional environmental plans and targets.We will assess a proposed GWP* method which states that methane from biotic sources does not behave the same as methane from fossil sources.This study will assess the feasibility of including this method in environmental impact assessments of organic dairy farms and the overall impacts in the analyzed scenarios.Objective 4.Materials from this work will be directly translated to a variety of extension and outreach materials for use by stakeholders. The PIs have extension positions and will include the outcomes of this work in their outreach efforts beyond industry to other stakeholders such as producers, policymakers, and the public. This includes developing peer-reviewed extension materials and presentations to a wide number of stakeholders. The information will be translated for industry stakeholders including an existing partnership with Organic Valley and PI Silva's existing extension network for organic production including Westby Creamery, Stonyfield, and the Organic Trade Association Dairy Council. The information will be developed to be able to guide industry partners into making targeted reduction strategies for their milk production and to make direct practice recommendations to their producers through their sustainability initiatives.