Soil Matters: NC State Maps Where Fertilizer Inhibitors Work

A three-year NC State study shows nitrogen inhibitors cut farm emissions, but their effectiveness depends heavily on soil type

13 Mar 2026

A three-year field study by North Carolina State University suggests that the effectiveness of fertiliser inhibitors in reducing farm emissions depends heavily on soil type, offering new evidence that could reshape nitrogen management on US cropland.

The research, funded by the US Department of Agriculture’s Natural Resources Conservation Service, examined the impact of dual urease and nitrification inhibitors across 18 corn farms in North Carolina. The project, known as the Beyond Yield study, tested the products under varied field conditions and was published in February 2026.

Researchers found that inhibitors consistently reduced nitrous oxide emissions when applied to clay and loam soils. On the sandy soils common in eastern North Carolina, however, the reductions were less reliable.

Ammonia emissions fell more consistently. Across most farms in the study, the inhibitors lowered ammonia losses regardless of soil type, suggesting that some environmental benefits remain even where nitrous oxide reductions are uncertain.

The findings highlight the limits of uniform fertiliser recommendations. Agronomists have often promoted enhanced efficiency fertilisers broadly across regions, but the study indicates that soil characteristics may play a decisive role in determining results.

The research also examined crop productivity under different fertiliser rates. Farmers who applied nitrogen at roughly half the conventional rate recorded little difference in corn yields, whether inhibitors were used or not. The result raises the possibility that some farms could reduce fertiliser use without significant losses in output.

The economic implications remain under review. Lead researcher Alex Woodley is working with NC State agricultural economist Rod Rejesus to model potential returns from carbon credit schemes and government subsidies tied to lower farm emissions.

The study comes as interest grows in improved nitrogen management. The Foundation for Food and Agriculture Research recently issued a 2026 call for field trials of enhanced efficiency fertilisers in western North America and arid farming systems, with grants of up to $500,000 per project.

Researchers say further field evidence will be needed to determine where inhibitors offer the greatest environmental and financial value for growers.