Response of Kentucky Bluegrass to Urea-Based Fertilizers Formulated to Reduce Ammonia Volatilization and Nitrate Conversion.

A field study was conducted to evaluate the response of Kentucky bluegrass to granular applications of ¹⁵N-enriched urea-based fertilizers. Two fertilizer formulations to reduce ammonia volatilization and conversion of ammonium to nitrate were compared with unamended urea for visual color response, dry matter production, total Kjeldahl N levels, and ¹⁵N uptake over an eight week period. Treatments were also evaluated for ¹⁵N recovery in soil as total N, inorganic N, and potentially mineralizable N estimated by the Illinois Soil Nitrogen Test.