Fertilizer price shocks, tightening nutrient regulations, and pressure to cut methane and ammonia emissions have many livestock and mixed-crop farms rethinking their nutrient strategies. One of the most intriguing developments is on-farm nitrogen fixation—compact systems that use electricity to capture nitrogen from the air and bind it into plant-available forms without relying on large centralized factories. Among the leading approaches is plasma treatment that turns a farm’s own manure or digestate into a higher-value, low-loss fertilizer.

What on-farm plasma nitrogen fixation is

In simple terms, a plasma unit energizes air to create reactive nitrogen species, which are then absorbed into a liquid nutrient stream—typically cattle slurry, pig slurry, or anaerobic digestate. The result is a more stable, nitrogen-enriched fertilizer that can displace part of the synthetic nitrogen a farm would otherwise buy. Because it is done on-site, the process localizes fertilizer production, cuts transport, and can be timed to periods when electricity is cheaper or more renewable.

Companies and research groups in Northern Europe have piloted these systems for several years. A prominent example is Norway-based N2 Applied, whose units integrate with existing slurry stores and pumping systems. The concept is also influencing parallel efforts in small-scale “green ammonia” production, but plasma treatment of manure/digestate is the version seeing the most real-world farm trials.

How it works, step by step

1. Air in, plasma on: Ambient air is passed through a plasma reactor powered by electricity. The plasma activates nitrogen (N₂) and oxygen (O₂), forming nitrogen oxides (NO and NO₂).
2. Into the liquid stream: Those gases dissolve into a slurry or digestate flow, forming nitrous and nitric acids that react with ammonium in the liquid to produce nitrate/nitrite and ammonium nitrate in solution.
3. Natural acidification: The process acidifies the liquid, lowering pH enough to “lock in” ammonia, sharply reducing volatilization during storage and land application.
4. Stable, analyzed fertilizer: The treated liquid now contains a more predictable nitrogen profile—still organic matter-rich, but with a higher share of plant-available N and less prone to losses.

Why farmers are interested

Yield and nutrient efficiency

By converting a portion of nitrogen into nitrate and stabilizing ammonium, plasma-treated slurry can synchronize more closely with crop uptake, especially for grasslands and small grains. Trials in the UK, Scandinavia, and the Netherlands have reported higher nitrogen retention relative to untreated slurry and comparable yields when substituting part of synthetic N. The predictable nutrient analysis also makes it easier to implement variable-rate application.

Emissions and odor

Lower pH and reduced free ammonia translate into significant cuts to ammonia emissions from storage and spreading. Farmers also report reduced odors. There is growing evidence that the treatment lowers methane formation during storage by inhibiting the microbes that drive methanogenesis, supporting climate targets set by many countries and dairy supply chains.

Resilience to price swings

When fertilizer markets spike, a farm’s ability to produce part of its nitrogen onsite buffers costs. If the farm has access to low-cost electricity—onsite solar, wind, biogas CHP, or flexible tariffs—the economics can be compelling, especially when paired with incentives for emissions reduction and nutrient stewardship.

What it costs and what it saves

Economics depend on electricity price, unit size and efficiency, and the local value of avoided synthetic fertilizer and emissions. A simplified way to think about it:

• Electricity in: On-farm nitrogen fixation is an electrical process. Energy consumption figures vary by system and operating conditions, but total electricity cost per kilogram of nitrogen is the anchor number to compare against buying nitrogen in urea, AN, or UAN.
• Fertilizer out: If the treated liquid reliably provides plant-available N that replaces purchased N, the savings scale with both the amount and the consistency of nutrient analysis.
• Extras: Add the value of lower ammonia and methane emissions (where monetized), fewer trips with top-dressed synthetic N, and potentially improved soil biology thanks to organic matter retention.
• Capex and Opex: Units are containerized and sized for medium to large livestock farms or central stores serving multiple neighbors. Consider depreciation, maintenance, and seasonal utilization when calculating payback.

Many farms run side-by-side field strips for one or two seasons to confirm replacement rates and yield before fully banking on savings. The key milestone is proving that a given number of kilowatt-hours reliably displaces a predictable amount of purchased nitrogen without yield penalty.

Who is best positioned to adopt

• Dairy and pig farms with significant liquid manure volumes and existing slurry infrastructure.
• Biogas plants looking to upgrade digestate value, reduce storage emissions, and offer a more uniform fertilizer product to suppliers or customers.
• Cooperatives or contractor hubs that can spread capex across multiple farms and guarantee high utilization.
• Regions with surplus renewable electricity or flexible tariffs that reward off-peak consumption.

Integration with day-to-day operations

Storage and pumping

Plasma systems typically loop into the slurry store, treating batches and circulating to maintain uniformity. Because the liquid becomes more acidic, materials compatibility and pump selection matter; vendors specify linings and plastics that tolerate the lower pH.

Application hardware

The benefits are maximized when coupled with low-emission application methods such as trailing shoe or injection, which further cut volatilization. Flow meters and ISOBUS-compatible controllers help dose nitrogen precisely, and some farms add near-infrared or ion-selective sensors for real-time nutrient verification.

Testing and calibration

Routine lab or on-farm analysis of total N, ammonium, and pH is essential. Many operators set application rates based on ammonium-N plus a portion of nitrate-N to ensure agronomic safety, refining rates by crop, soil, and timing.

Regulatory and safety considerations

• Nutrient rules still apply: Treated slurry remains manure-based and is usually subject to the same application limits and closed periods under nitrates regulations. In some regions, its improved stability can help farms meet ammonia reduction targets.
• Storage and handling: The liquid is more acidic and contains nitrate. Although concentrations are far below levels associated with explosive risk, standard precautions for acids and nitrate-bearing fertilizers apply. Follow vendor and local safety guidance.
• Permitting: Depending on jurisdiction, installing a treatment unit may require notices or permits related to electrical infrastructure, emissions reporting, or changes to nutrient management plans.

How it compares to other options

• Sulfuric acid acidification: A well-established way to reduce ammonia losses from slurry by lowering pH. Plasma treatment achieves pH reduction while also adding reactive nitrogen, but with higher capex and electricity demand rather than trucked-in acid.
• Nitrification inhibitors: These slow conversion of ammonium to nitrate in soil, reducing leaching and nitrous oxide. They complement plasma-treated fertilizers but don’t address storage emissions.
• Covered or enclosed storage: Reduces emissions and rainwater dilution. Often used alongside plasma systems to lock in gains.
• Small-scale green ammonia units: Containerized systems that synthesize ammonia from water, air, and electricity, typically for use as fertilizer or on-farm fuel. A promising complement for arable farms with less manure, though still early-stage in most regions.

What to watch over the next three years

• Independent performance data: More multi-season trials across crops and soils will clarify typical replacement rates for synthetic N and quantify methane and ammonia reductions under real farm conditions.
• Efficiency gains: Reactor designs, heat recovery, and smarter controls could reduce energy per kilogram of nitrogen fixed, improving operating cost and carbon footprint.
• Policy signals: Incentives that reward verified ammonia and methane cuts, or recognize low-carbon fertilizer in supply chain programs, would accelerate adoption.
• Pooling models: Cooperative ownership and contractor-operated units treating manure for multiple farms could raise utilization and lower costs per liter treated.
• Interoperable nutrient data: Seamless flow of lab and sensor data into farm management software and variable-rate maps will make precision application routine.

Practical checklist for interested farms

• Quantify annual slurry or digestate volumes and current nitrogen losses and purchases.
• Audit electricity supply: peak/off-peak rates, available capacity, potential for solar/wind/biogas coupling.
• Plan for storage, circulation, and materials compatible with acidic liquids.
• Specify application kit (trailing shoe/injection) and nutrient testing workflow.
• Run small, well-documented field comparisons for at least one season before fully committing replacement rates.
• Engage regulators early to align with nutrient and emissions compliance.

Bottom line

On-farm plasma nitrogen fixation is not a silver bullet, but it offers a compelling way to turn a waste challenge into a fertilizer asset while tackling ammonia and methane emissions. For livestock and digestate-heavy operations, the technology can improve nutrient reliability, enhance sustainability metrics, and bring part of fertilizer production under the farm’s own control. As energy systems decarbonize and policies begin to value verified emission cuts, the farms that pilot and learn this approach now will be best positioned to capture both agronomic and economic upside.