Keeping nitrogen available for crops is a significant challenge in agriculture due to losses through volatilization, leaching, and denitrification. Two common approaches to nitrogen stabilization are the use of NBPT and humic acid.
NBPT, or N-(n-butyl) thiophosphoric triamide, is a synthetic urease inhibitor widely used with urea and UAN fertilizers. Its main function is to slow the conversion of urea to ammonia near the soil surface. By temporarily blocking the urease enzyme, NBPT delays hydrolysis for three to fourteen days depending on environmental conditions. This delay allows more time for rainfall or incorporation to move nitrogen deeper into the soil, reducing volatilization losses.
Humic acid, in contrast, is derived from decomposed plant material and consists of complex carbon molecules that help soil retain moisture and nutrients. Instead of blocking nitrogen loss directly, humic acids capture and hold onto nitrogen and other nutrients, giving plants and microbes more time to use them before they are lost from the system. Soils rich in humic acid have higher cation exchange capacity (CEC), which improves nutrient retention but has a more variable effect on nitrogen efficiency compared to NBPT.
NBPT provides short-term protection against volatilization when surface-applying urea or UAN under conditions where rain or incorporation may be delayed. Humic acid is best used for long-term soil improvement in soils with low organic matter or poor structure.
Both products can be used together since they work through different mechanisms—NBPT offers immediate protection while humic acid supports longer-term nutrient cycling. “Used thoughtfully, each has its place. Used together, they can complement each other—one protecting nitrogen today, the other improving the soil’s ability to conserve and cycle nutrients tomorrow,” according to Farmer’s Business Network (FBN).
FBN offers various products for both strategies including Inhabit N (urease inhibitor), Inhabit Start (with phosphorus and potassium), OM 1-3mm (humic acid product by Huma Inc.), and Inhabit Boost (carbon source with nitrogen). These products are delivered directly to farms through FBN Direct.
Farmers are advised always to follow label directions when using these products and ensure compliance with federal and state regulations regarding pesticide use.
For further information about FBN’s offerings on nitrogen stabilizers and biologicals, visit their website.