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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Environmentally Integrated Dairy Management Research » Research » Research Project #430943

Research Project: Reactive Nitrogen Cycling and Impacts on U.S. Dairy Farms: The Feasibility of Sustainable Milk and Agro-Ecosystems

Location: Environmentally Integrated Dairy Management Research

Project Number: 5090-12630-006-025-I
Project Type: Interagency Reimbursable Agreement

Start Date: May 15, 2016
End Date: May 14, 2023

The goal of this project is to advance N use efficiency in U.S. dairy farm systems, emphasizing the multiple objectives of sustaining economic productivity while minimizing off site impacts. We will carry out state-of-the-art, comprehensive analyses of reactive N cycling and management for the prominent dairy farm systems across the U.S. We will analyze and quantify the farm-scale air and water quality impact and economic viability of dairy systems by modeling reactive N cycling in four geographically distinct, integrated, dairy production systems (PA, WI, MN, and ID). Supporting objectives include: 1. Identify sources of farm-scale N loss and use inefficiency, focusing on areas of greatest potential impact in wide variety of dairy systems. 2. Identify new dairy farm practices and systems that significantly improve N use efficiency and N losses, and quantify their farm-scale economic and environmental costs and benefits, including synergies with carbon and phosphorus cycling. 3. Improve education and communication between researchers and farmers/farm advisors using simulation models as decision support tools. The project will focus primarily on reactive N because N cycling touches all aspects of farm production as well as environmental impacts, including water quality, air quality, and climate change. However, carbon (C) and phosphorus (P) cycling and environmental impacts are arguably impossible to separate from N. Therefore, we will also consider how changing farm practices for N management impact phosphorus (P) use and loss to the environment. Two team members are experts on agricultural P management, so we will examine P results closely to ensure an integrated nutrient management. Because the model used in the project (IFSM, see discussion below) also simulates greenhouse gas emissions (CO2, CH4) from farms, we will also consider these gas emissions at a similar level as P.

We will use the Integrated Farm Systems Model (IFSM) to simulate N cycling on a variety of dairy farms representing the production practices and climates of four dairy regions in the U.S.: the Northeast, the Upper Midwest, the northern Great Plains, and the West. We will visit farms and use interviews and sampling to collect information for input into IFSM. We will simulate each farm in IFSM, including production, costs, and environmental impact. Predicted farm performance will be affected by the relationships and parameters used to simulate individual farm components. We will perform a sensitivity analysis to determine which input and internal model parameters have the greatest impact on productivity and environmental impact. We will assess productivity through crop and milk production, and environmental impact through N gas emission and nitrate leaching. We will also assess production costs. We will use other parameters to evaluate N cycling related to N use efficiency (NUE) on the farm. The goal of the sensitivity analysis is to identify practices and processes that have the greatest impact on N cycling, use, and loss. After the sensitivity analysis, we will simulate the impact of changing a range of farm practices and model parameters on crop and milk production, N loss, and farm economics. We will analyze results of the alternative farm production simulations to determine the environmental and farm cost impacts of different dairy production systems. Impacts to be evaluated include milk and crop production, N loss through gaseous emissions and nitrate leaching, and farm costs and revenues. On a subset of farms, we will conduct visits and explore how decisions are made concerning management practices and approaches, especially related to systems decisions where models could be used. Questions will be asked to see if models are used in decision-making, what kinds of model are used, who uses the models, and why those models were chosen. Questions will be asked about farmer-researcher interactions, if farmers have had previous experiences with researchers, the positive and negative aspects of previous experiences, and if models were ever used in those interactions. After the first visits, we will simulate the farms in IFSM and analyze the quantitative results. We will conduct alternative management scenario simulations to generate information on practices that could be implemented to improve NUE or reduce N loss. We will conduct second visits to share IFSM results with farmers and get impressions about results alternative scenarios. This will be an opportunity to use IFSM to develop communications with farmers and explore if IFSM can create a valuable enough “experience” for farmers to influence their decision making in practice. We will implement ideas about model modifications and alternative management simulations generated in the second farm visits and then conduct final visits to discuss changes and simulations. Final visits will explore barriers for farmers to use a model like IFSM in planning, or what kind of model they would be willing to use or would add value to their operation.