Fertile Ground for Reform: A Research Roadmap for Agricultural Nitrogen Pollution

The Environmental and Energy Study Institute (EESI) and the Natural Resources Defense Council (NRDC) held a briefing about tracking and reducing agricultural nitrous oxide, a major greenhouse gas. Nitrogen is a key component in fertilizer, making it critical to food security. Unfortunately, due to overapplication, only about half of nitrogen fertilizer is actually absorbed by crops. This leads to high levels of nitrous oxide emissions and threatens drinking water, ecosystems, and public health. Nitrous oxide has a global warming potential 273 times greater than carbon dioxide over 100 years and is the primary driver of stratospheric ozone depletion, increasing UV exposure and associated health risks. Nitrous oxide measurement, monitoring, reporting, and verification mechanisms are essential to reducing these emissions and supporting profitable and sustainable farm management.

This briefing showcased findings from a new research roadmap that identifies opportunities for measuring and reducing agricultural nitrous oxide emissions. Panelists pinpointed areas of innovation, as well as opportunities for reducing uncertainty, improving accuracy, bringing down costs for farmers, and reducing nitrogen loss from fields. The briefing also helped policymakers identify research and development needs, and highlighted the role of federal and state legislatures in improving environmental, economic, and public health across the country. 

 

Highlights

KEY TAKEAWAYS

When farmers overapply nitrogen fertilizer to their fields, the excess fertilizer leaches into groundwater or flows into nearby water bodies. Nitrogen can also enter the atmosphere as nitrous oxide (N₂O) and contribute to ozone layer depletion and rising global temperatures, posing risks to public health. Farmers want better data to prevent fertilizer overapplication and save money. The sensors, models, and artificial intelligence tools to provide this data exist, but they have to be reliable, effective, trustworthy, and easy to use. Measurement, monitoring, reporting, and verification (MMRV) technologies allow for precise measurement, robust modeling, and transparent reporting, helping researchers bridge information gaps, allowing for more accurate fertilizer application, saving farmers money, and reducing greenhouse emissions and their associated health risks. A new research roadmap developed by the Natural Resources Defense Council (NRDC), scientists, and industry experts, aims to transform N₂O MMRV and modeling, identifying information bottlenecks and policy pathways to address them.

 

Rep. Sean Casten, U.S. Representative (D-Ill.)

• Nitrous oxide (N₂O) has a global warming potential almost 300 times greater than that of carbon dioxide over 100 years. So you only need to reduce these emissions by a little bit to make a big difference.
• Farmers are overapplying fertilizer to their fields, which results in N₂O emissions. Reducing these emissions by reducing fertilizer input can help farmers’ wallets in the long run—and even earn them voluntary carbon credits. Monitoring and data collection can help farmers make these cuts. 

 

Rachel Opitz, Program Manager, Geospatial Innovation for Food Security, Taylor Geospatial

• Contemporary farming practices that provide high crop yields and an abundance of food production depend on applying fertilizers to soils to boost crop growth. But it is difficult to accurately predict each plant’s nutrient needs based on differing environmental conditions, so farmers err on the side of caution and overapply. 
• Excess fertilizer leaches into groundwater, polluting drinking water systems and creating toxic algal blooms. Leftover nitrogen can also enter the atmosphere as N₂O and contribute to ozone layer depletion and rising global temperatures, posing risks to public health.
• More than 80% of human-caused N₂O emissions come from agriculture. Emissions are projected to increase as farming operations scale up and intensify.
• Universities, government agencies, and the private sector are actively working to address N₂O emissions, but are limited by data gaps. Current N₂O emission monitoring is not standardized, being carried out in a patchwork by disparate research groups using different technologies. Farmers also often lack the technical and fiscal capacity to monitor emissions on their fields. 
• Measurement, monitoring, reporting, and verification (MMRV) technologies allow for precise measurement, robust modeling, and transparent reporting. These will in turn help researchers bridge information gaps, allow for the development of more accurate fertilizer application methods and technologies, save farmers money, and reduce greenhouse emissions and their associated health risks.
• MMRV is also key for farmers, agri-food businesses, and fertilizer manufacturers looking to participate in voluntary or government programs that provide payment or credits for fertilizer reduction. These programs require regular submission of emissions data.
• The Natural Resources Defense Council (NRDC) collaborated with 25 scientists and industry experts to develop a research roadmap to transform N₂O MMRV and modeling. The report identifies four key research bottlenecks: unreliable sensors, uncertainties from inefficient and unscalable models, lack of coordinated and interoperable datasets, and disagreement on collective vocabularies and data governance.

 

Maria Bowman, Program Director, Agricultural Nitrogen Transformation, Spark Climate Solutions

• In 2026, commodity and fertilizer price volatility have made reducing input costs for farmers particularly crucial.
• Nitrogen management decisions involve not only how much nitrogen to apply, but also the type of fertilizers to apply, when to apply them, and how. Each decision affects how much nitrogen is available, and how much is lost. 
• Farmers often use experience and historical data, such as from yield and soil maps, to make fertilizer use decisions. They also refer to recommendations from trusted advisors and nitrogen rate calculators.
• Precision agriculture technologies such as variable rate technologies play a key role in helping farmers get the data they need to develop and implement a variable rate of nitrogen application across their fields based on yield and soil maps. 
• Soil testing helps farmers understand how much nitrogen is left in their soil. The Late Spring Soil Nitrate Test, for example, determines how much nitrogen has been mineralized by the soil, which helps farmers decide how much fertilizer to use during the growing season. 
• About 80% of U.S. corn acreage relies on rainfall rather than irrigation, and the influence of weather on the “right” nitrogen rate is a fundamental challenge for fertilizer application. Nitrogen rates also vary from field to field and year to year, sowing uncertainty that leads to the overapplication of fertilizer. 
• Farmers want better data to prevent fertilizer overapplication and save them money. The sensors, models, and AI tools to provide this data exist, but they have to be reliable, effective, trustworthy, and easy to use.
• Fertilizer use efficiency has improved over the last 15 years with the introduction of enhanced-efficiency fertilizers and inhibitors that keep nitrogen in the soil for longer. But at least a quarter of nitrogen inputs from fertilizers and manure are still being lost at the crop production stage. Research and development to improve existing tools and create new ones are key to bolstering nitrogen use efficiency in crops.
• A report by the U.S. Department of Agriculture’s (USDA’s) Economic Research Service found that less than half of large farms use variable rate technologies to apply fertilizer. This may be attributed to equipment capacity issues on farm operations. Continued adoption of precision agriculture will require farmers to purchase new equipment and learn how to use it, so it is important to ensure they have support systems in place to address technical capacity issues.
• MMRV can also be applied in livestock operations to improve the recyclability of manure. Research published in March 2026 found that manure could meet up to 21% of fertilizer demand with technological innovations, compared to 5% with existing technology. 
• Spark Climate Solutions is working to address nitrogen loss in agriculture and livestock operations by developing new crop varieties, including those that target nitrogen use efficiency. 
• Improvement in MMRV requires investing in relationships with farmers to earn their trust and encourage their participation. 

 

Rep. Rick Hansen, Minnesota State Representative

• The nitrogen cycle is inherently leaky, and nitrogen applied as fertilizer can escape into groundwater as nitrate or into the atmosphere as N₂O. While laws and policies can change, the underlying chemistry cannot. 
• Nitrate groundwater contamination has been a known health concern for decades and is linked to conditions such as methemoglobinemia, or “blue baby syndrome.”
• Minnesota last updated its pesticide and fertilizer law in 1987 and passed the Groundwater Protection Act (SF 262) in 1989. The Minnesota Department of Agriculture and Nitrogen Fertilizer Task Force set the groundwork for the state’s first Nitrogen Fertilizer Management Plan in 1990, which outlines the state’s approach to managing nitrate groundwater contamination from fertilizers.
• In Minnesota, heavier rainfall and greater climate variability are fostering N₂O emissions from fertilizer overapplication by creating saturated, low-oxygen soil conditions favorable for N₂O formation.
• Applying anhydrous ammonia when soil temperature is below 50°F slows microbial activity and reduces nitrogen loss, but the fluctuating fall temperatures that Minnesota has experienced complicate timing decisions for farmers.
• Applying fertilizer in smaller, timed doses that match the crop’s nutrient uptake is considered the gold standard for reducing losses.
• Greenhouse gas and water quality policy should be considered together rather than separately because nitrogen losses to water and to the atmosphere stem from the same underlying system.
• Since 2008, Minnesota has dedicated almost $200 million per year in sales tax revenue to clean water efforts. A July 2026 state legislative audit found that Minnesota has spent $30 million on its voluntary Agricultural Water Quality Certification Program since 2013 without clear evidence of water quality improvement. This underscores the need for built-in evaluation components in future nitrogen policy.

 

Matthew Kaplan, Senior Attorney, Water and Agriculture Nature Program, Natural Resources Defense Council

• Agricultural N₂O emissions account for 75% of national N₂O emissions and 90% of Minnesota’s N₂O emissions.
• Accurate N₂O measurement is critical for carbon accounting and carbon markets. It also helps farmers reduce input costs by identifying nitrogen losses, supports corporate emissions reporting, and helps researchers understand how nitrate pollution is affecting local water quality and public health.
• NRDC’s research roadmap recommends that, at the federal level, funding agencies be made aware of the different types of technologies that can bolster N₂O emission reductions. Strategic partnerships between federal agencies (e.g., USDA and the U.S. Department of Energy) and business, farmers, and associated entities (e.g., the National Academies, National Labs, and National Science Foundation) are also key to mitigating N₂O emissions.
• States are the primary actors of policy innovation, as they are closer to feedback loops around resource management, budgets, and local issues.
• Philanthropy and business also have an important role to play in translating the research priorities outlined in the report into the long term.
• NRDC will continue to engage N₂O researchers, farmers, the private sector, and federal and state policymakers as the MMRV roadmap guides future research coordination and policy work.

 

Q&A

 

Q: What states, universities, or producers are leading the way on N₂O-related MMRV innovations, and which might serve as replicable models?

Opitz

• The University of Minnesota’s AI-LEAF Institute—funded by the National Science Foundation and the National Institute of Food and Agriculture—is a pioneer in knowledge-guided machine learning for modeling the nitrogen cycle and N₂O emissions.
• Other leading work includes Colorado State University’s Natural Resource Ecology Laboratory, Colorado’s Ecosystem Modeling and Data Consortium, the AmeriFlux eddy covariance network, and the development of uncrewed aerial vehicle-based N₂O sensors at Princeton University.

Bowman

• The NASA Acres program is working on Earth-observation technology, specifically in nitrogen management. Teams at Purdue University and the University of Illinois are also connecting Earth-observation data with on-farm research, decision-support tools, and nitrogen modeling.
• Pilot programs—such as that of Practical Farmers of Iowa—have been pairing farmer networks with market incentives to help producers reduce nitrogen application while layering in additional MMRV research.

Hansen

• State licensing programs for fertilizer dealers track fertilizer sales and could offer a basis for federal data aggregation and ground truthing fertilizer use. However, sales data reflects when and where fertilizer is sold, rather than actual field application.
• Tax policy could offer another path for tying incentives to nitrogen and water quality monitoring. For example, fertilizer purchase timing interactions with Schedule F farm income reporting, 1031 exchanges, and Section 179 depreciation could inform management practices for other water contaminants.

Kaplan

• The California Air Resources Board has developed significant expertise and could model interstate coordination on a national nitrogen research agenda.
• Practical Farmers of Iowa’s nitrogen trial work has influenced nitrogen management practices in Minnesota.

 

Q: Amid global supply disruptions affecting fertilizer feedstocks routed through the Strait of Hormuz, how might MMRV and fertilizer-reduction strategies help shield producers?

Bowman

• Farmers are currently squeezed by both high fertilizer costs and low commodity prices, and they want reliable decision-support tools that let them confidently reduce applications without risking yield and income.
• Longer-term innovations that improve nitrogen use efficiency—such as new crop varieties or better use of substitutes like manure—could also reduce fertilizer demand.

Hansen

• Most U.S. nitrogen fertilizer is produced through the Haber-Bosch process from petrochemical feedstocks sourced largely from the Gulf of Mexico or Canadian natural gas. Tariffs affect that supply’s flow and cost
• Four large companies control much of the U.S. fertilizer market, and breaking up that concentration could reintroduce competition and diversify sources.

Opitz

• MMRV is essential to helping farmers access alternative income streams, such as carbon credit markets, during supply chain disruptions.

Kaplan

• Better long-term data connecting field-scale fertilizer application to N₂O emissions pathways would help farmers use limited resources more efficiently.

 

Q: In the Farm Bill reauthorization process, what specific N₂O programs or provisions should Congressional staff pay attention to?

Kaplan

• Nitrogen MMRV has received less legislative attention than carbon MMRV. The research roadmap is intended to help guide the science before nitrogen markets mature further.
• USDA offices like the National Institute of Food and Agriculture, Agricultural Research Service (ARS), Natural Resources Conservation Service (NRCS), and Office of the Chief Economist each contribute to nitrogen MMRV research and development. USDA could also help coordinate across federal agencies—including National Science Foundation quantum sensing programs—on shared long-term MMRV goals.

Hansen

• I proposed a Farm Bill-funded catalyst program in Minnesota allowing farmers to apply for small grants to try on-farm N₂O-reduction experiments.

Bowman

• Existing USDA and NRCS innovation programs, such as those supporting cover crops, have been successful models but have not specifically focused on nitrogen management. Similar funding and interagency coordination, especially with ARS, could be directed toward nitrogen-specific innovation.

 

Q: Are there conservation practices that, while beneficial for one purpose, might inadvertently increase N₂O emissions?

Hansen

• Tile drainage can reduce soil saturation and associated N₂O emissions, but it can also increase nitrate runoff into surface water or groundwater. There are trade-offs within this leaky system.

Bowman

• Pairing drainage practices with nitrate management tools at tile drain outlets could address both nitrate and N₂O concerns simultaneously, but the added cost makes producer incentives and support important.

Kaplan

• Generating better data on the relationship between specific practices and their downstream consequences is central to the research roadmap’s long-term research strategy.

 

Q: Closing thoughts?

Opitz

• The technologies needed for robust N₂O measurement and monitoring are not decades away—they are achievable within the next five to 10 years. The research roadmap can help put the necessary coordination in place now.

Bowman

• Reducing nitrogen losses requires a systems approach spanning crop practices, livestock feeding, and manure management, supported by policy and market incentives. Spark Climate Solutions plans to publish related research later this year.

Hansen

• Supporting science means supporting people, which in turn requires sustained investment in research funding at the federal and state levels, including for academic institutions.

Kaplan

• State-level resource agencies play a substantial role in driving tech innovation, since state policy often sets the direction. Thinking about where we want to be 10 years from now can help us decide which technologies are most important to back today.

 

Compiled by Megan Davies and Jasmyn Mirsepahi and edited for clarity and length.