Soil Type Holds the Key to Fertilizer Efficiency Gains

NC State research finds enhanced efficiency fertilizers cut emissions on clay soils but deliver weaker results on sandy ground

24 Apr 2026

New research from NC State University is delivering some of the most detailed on-farm emissions data the fertilizer industry has seen, and the findings carry real implications for how nitrogen is managed across US corn production.

A three-year study led by soil scientist Alex Woodley tracked nitrous oxide and ammonia emissions across 18 working corn farms in North Carolina. The research tested dual urease and nitrification inhibitors added to conventional nitrogen fertilizers, a class of enhanced efficiency fertilizers designed to slow nitrogen conversion and keep more of the nutrient available to crops. The results confirmed measurable emissions cuts, but with a finding that changes the calculus for broad adoption: performance depends heavily on soil type.

On heavy clay and loam soils, where saturation conditions drive nitrous oxide release, the inhibitors worked well. On sandy soils, where drainage is faster and saturation less likely, the effect was significantly reduced. That distinction challenges the industry's tendency toward uniform product recommendations and points clearly toward precision, site-specific application.

Equally significant for growers managing input costs was the yield data. Cutting nitrogen rates to half the standard level had minimal impact on corn yields across most test fields. For farmers, that finding suggests leaner nitrogen programs may be achievable without sacrificing output, a combination that could lower costs while reducing environmental load.

NC State is now pairing the emissions findings with an economic analysis led by agricultural economist Rod Rejesus to determine whether inhibitor costs are justified on yield grounds alone. Early signals suggest the yield case may be tight, but the environmental argument, particularly in regions with nutrient runoff rules and sensitive waterways, could drive adoption through conservation incentives and sustainability-linked supply chain requirements.

With independently validated, field-scale data now entering the conversation, the research is well positioned to influence both agronomic guidance and policy decisions in the years ahead.