In New Mexico, tests evaluated urea, UAN, Agrotain, and dairy manure on corn and irrigated cotton.

There was no effect of nitrogen source or timing on fresh weight of corn. Dry matter yield was similar to applying 11-52-0 only, suggesting that nitrogen was not sufficiently mineralized from the manure application in time to contribute to yield. Crude protein content was lower in the corn plant from both manure application rates compared to UAN and urea treatments.

Estimated milk production on a per acre basis tended to be greatest from corn treated with one application of UAN, urea, or urea treated with Agrotain over two applications (greatest numerical yield). Applying manure at an application rate that estimates 35 percent mineralization may have contributed excessive salt to the soil and decreased plant dry matter accumulation. Fertilization of cotton had no impact on cotton yield. The nitrogen sources used had no impact on cotton yield or fiber quality.

North Carolina

Wheat and corn production tests in North Carolina included UAN solution, Nitamin (UFP), ESN, and Nutrisphere at various rates.

The wheat data suggest that UAN, NutriSphere, and UCAN produced similar grain yields for all four site years. The ESN yields were lower than the other fertilizers for one site year. The use of ESN for wheat straw production is not recommended as it produced lower yields 75 percent of the site years. The use of any of the alternative nitrogen fertilizer products over UAN for wheat grain production would be heavily influenced by fertilizer pricing.

Over the six site years of corn grain yield data, five demonstrated no agronomic advantage of the alternative fertilizer products over UAN for grain production. In the one site year, UAN produced less grain than the alternative fertilizer products; this may have been due to a change in tillage system. In three of the six site years, NutriSphere and ESN produced higher corn stover yields than UAN. Two of those years were in the mountains, suggesting that NutriSphere may offer an agronomic advantage over UAN in the production of corn stover in the mountains under the field conditions in this study.

A separate incubation study demonstrated that UCAN and NutriSphere released nitrogen on a time scale similar to UAN under the laboratory conditions. The release time for ESN in the five soils was approximately 7 to 42 days and was slower than UAN, NutriSphere, or UCAN.

Overall, the use of these alternative nitrogen fertilizers in North Carolina provides little agronomic benefit to corn or wheat grain production. Producers who use the products for stover or straw production should be aware of cost differences between products.