Pollution Mitigation Practices in Agriculture: Incentives, Practices, and Policies
Agriculture provides food for humans, fiber, and livelihoods for billions of people worldwide and is a critical resource for sustainable development in many regions. Regardless, agriculture also provides many ecosystem services and opportunities for climate change mitigation and removal of greenhouse gases (GHG).
Our March webinar focused on the importance and significance of land management practices in reducing carbon emissions. In addition, that webinar discussed the priority of introducing "climate-smart" agricultural practices on U.S. farms and ranches. In this webinar, we continue the conversation while shifting the focus from carbon to nitrous oxide and methane. Agricultural soils are a dominant source of nitrous oxide pollution, as is the management of manure or the burning of agricultural residues. However, what policy tools can we use to reduce these pollutants while supporting sustainable and resilient agricultural supply chains?
Jeff O’Hara opens the webinar with a presentation titled “Direct Green House Gas Emissions from U.S. Livestock Farms”. Currently about 4 percent of greenhouse gas (GHG) emissions occur from livestock farms in the U.S. predominantly in two forms:
Enteric fermentation (3 percent) – Mostly from cattle, methane emissions that arise when cattle breathe or release methane from their stomach.
Manure management (1 percent) - GHG that arise from manure, methane occurs when manure decomposes anaerobically (i.e., without oxygen)
Grasslands – Can be soil carbon sink or source depending on grazing practices
Reducing methane emission is important because it has a higher global warming potential than carbon dioxide. There is a possibility of nearer-term reductions given structural challenges with CO2 emission reductions. In 2021, the U.S. launched the Global Methan Pledge to reduce global methane levels by 30 percent in 2030 relative to 2020. California, the biggest diary state in the U.S., also has a livestock methane reduction target. The USDA has also enacted policies that focuses on the reduction of livestock GHG emissions such as Partership's for Climate-Smart Commodities that creates new/expands existing markets for “climate-smart” agricultural commodities.
The next panelist, Ben Gramig, continues the webinar with a presentation on “Nitrogen Pollution Abatement Opportunities in U.S. Row Crop Agriculture”. Agriculture is a major source of nitrogen pollution in the U.S. surface and coastal waters. Nitrogen in animal manure and inorganic fertilizer that is not fully utilized by crops is lost from farm fields under two conditions. First is the excess of nitrogen is washed from fields during rain and snow melt events. The second is when nitrogen leaches through soil into groundwater or artificial drainage lines that deliver excess water to ditches.
High level of nitrogen (and phosphorus) can cause eutrophication that leads to hypoxia and harmful algal blooms in fresh water which leads to unsafe conditions for water contact. Nitrogen loss abatement practices are available to help address whether GHG emissions from agriculture trace back to nitrogen and water pollutions. Typically focuses on fertilizer management or the 4Rs: the right rate, timing, placement, and source. Recycle or scavenge excess nitrogen for subsequent crop using cover crops.
Next, panelist Brent Avermann presents, “Livestock, Methane, and Water Management in the Southwest”. Beef is produced in many ways, however despite the many different systems, beef almost always starts on a pasture or rangeland. Below is a diagram of the five different systems cattle can go through to slaughter to packaging plant.
The production phases typically feature cow-calf, stockers, backgrounders, and feed yards. In addition to enteric methane production, water varies widely with the production system.
Beef cattle drink about 10-15 gallons per head per day of water. In confinement, grain may be irrigated or not. Depending on the location of the farm, some grain is irrigated such as in the Texas high plains. About 2/3 of fed corn is railed into the southern high plains. Feed in the Midwest may not be irrigated and much of the water comes naturally in the rain fall. Really depends on the sourcing of the grains.
To close out the webinar, the last panelist, Steven Wallander, presented “Agricultural Conversation Policy Overview”. With an economist perspective, policies are divided into two different silos for options for encouraging pollution abatement on agricultural production systems. There are voluntary approaches which from the agricultural perspective are the most common especially through USDA programs, cap and trade markets, and NGO and commodity buyer incentives. The second are regulatory approaches such as federal programs like the Clean Water Act and state programs like Nutrient Management Plan requirements.
Two major USDA Working Lands Programs are now about 3 billion dollars per year. Now a little over half of the funding is going towards these Working Lands Programs specifically the Environmental Quality Incentives Program and the Conservation Stewardship Program. In terms of nutrient and GHG related practices, written nutrient management plans are very important as they are much more involved. To close, Wallander discussed the technical assistance USDA provides. About 20 percent of major crop fields have poor drainage as a self-identified resource concern. However, about 20 percent of those identified fields have received technical assistance. There is still room to target and expanded technical assistance.
Questions and Answer
What is the current status of the carbon offset market and agricultural participation in the carbon exchanges?
Anaerobic digesters are the only climate-smart practice that has registered offsets to-date in California’s Cap-and-Trade Program. In recent years, anaerobic digesters have migrated from getting offset credits to getting credits in California’s Low Carbon Fuel Standard. This is because older digesters combusted the methane biogas to generate electricity, whereas newer digesters are cleaning the biogas and injecting it into a pipeline where it will be used as a transportation fuel in the form of compressed natural gas.
Otherwise, offset markets have not incentivized climate-smart farming practices at scale. The offset protocols developed have had high transaction costs for farmers relating to a) quantifying emission reductions, b) ensuring that the practice is maintained for a long time (soil carbon gains can be reversed when the practice is discontinued), and c) requiring farmers to maintain the practice is “additional”.
In response to these challenges, USDA recently launched a new Partnerships for Climate-Smart Commodities Program. This program is intended to create new and expanding existing markets for agricultural commodities that are produced with climate-smart practices. More details on this program are here: https://www.usda.gov/climate-solutions/climate-smart-commodities.
Has the value certain ecosystem services related to pollution mitigation been quantified, e.g. cover crops, perennial hedgerows along riparian zones?
We are not aware of ecosystem service value estimates for specific individual practices. While possible, more common has been valuation of a service (water quality regulation or pest control) and then quantification of the amount of that service provided by a specific practice.
Can we expect post plant application to increase for non-cover crop acres?
There was an observed increase of approximately 4% of total N fertilizer application from spring pre-plant to post-plant on all corn acres (with and without cover crops) between 2010 and 2016. We cannot say whether this trend will continue, but have observed a larger share N fertilizer being applied post-plant on cover cropped corn (2010 and 2016) and cotton (2015 and 2019) fields in the most recent ARMS surveys.
What effect does the Clean Air Act have on driving mitigation efforts? Or is agriculture largely exempted from the requirements?
The Clean Air Act does not directly address greenhouse gas pollution from any industry, including agriculture.
The Clean Air Act pertains to direct mitigation of GHGs per se. Highly motivated regulators at all levels have a way of cleverly using authority that they DO have under federal statutes (whether direct, in EPA’s case, or delegated, in the cases of some state air pollution regulatory agencies) to shado-regulate emissions over which they have no authority. Thus, for example, neither is ODOR an area in which EPA has direct regulatory authority…but witness the hubbub in the early 2000s when CERCLA and EPCRA were used as convenient vehicles to regulate two trace odorants, H2S and NH3, that are emitted by livestock. Similarly, livestock-derived fugitive dust, which is not explicitly included in calculations for Title V major-source determinations with respect to e. g. PM10 or PM2.5, is an odor-carrying vehicle, and enterprising regulators are occasionally inclined to use CAA instruments such as the compliance monitoring system for the National Ambient Air Quality Standards (NAAQS) as property-line quasi-enforcement tools for odor-related nuisance.
This program is supported in part by the Agricultural and Applied Economics Association and the US Department of Agriculture’s Economic Research Service, and the National Agricultural Statistics Service.
Those who register but cannot attend our webinar can always view a recording of it later at the council’s YouTube channel.