Nitrogen Use Efficiency and Yield Effects of Urea Formaldehyde Polymer (UFP) Fertilizer in Winter Wheat and Maize.
Sheri L. Cahill, Deanna Osmond, Carl Crozier, and Randy Weisz. NCSU, Soil Science Department, Raleigh, NC 27695
The potential for improved fertilizer Nitrogen Use Efficiency (NUE) and yield was tested during a two-year field experiment in North Carolina from 2004 to 2006 in winter wheat (Triticum aestivum L.) and maize (Zea mays L.) as influenced by a common N fertilizer (30% N solution as Urea-Ammonium Nitrate) (UAN) and a new, controlled-release urea (Urea Formaldehyde Polymer) (UFP). The crops were grown on Candor (Sandy, siliceous, thermic Grossarenic Kandiudult), Portsmouth (Fine-loamy over sandy or sandy-skeletal, mixed, semiactive, thermic Typic Umbraquults) and Cape Fear (Fine, mixed, semiactive, thermic Typic Umbraquult) soil. The sandy soil was irrigated as needed to avoid drought stress. The experiments were arranged as randomized complete blocks with four replicates. Treatments were N source (UAN and UFP) and N rate (0, 42, 84, 126, 168, 210, 252 kg N/ha for maize and 0, 54, 84, 114, 144, 174, 204 kg N/ha for wheat). UAN and UFP were applied as a split application for wheat, while maize received UFP at planting and split UAN. Timing of the materials was determined by either label (UFP) or prior experimental experience (UAN). There was no significant difference of NUE between the UAN and UFP during the first year. Soil samples were collected from control plots and highest N rate for each fertilizer type and each crop. Profile soil NO3 (0-20cm and 20-40cm) did not significantly differ between the two N fertilizers. Since the cost of UFP is substantially greater than UAN fertilizer and form does not affect yield, UFP is not economically viable.