Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 7/5/2000
Publication Date: N/A
Technical Abstract: High N and irrigation amounts applied to the potato crop on coarse-textured soils are often associated with leaching and low recovery of N. This study compared the effects of two rates (140 and 280 kg N/ha) of a single polymer-coated urea (PCU) application versus three urea applications on leaching and efficiency of N in potato production under standard irrigation nin 1997 through 1999 and under excessive irrigation as well in 1999. An additional urea treatment at 280 kg N/ha was added in five split applications. A zero N control was included in each replication. At the recommended rate of 280 kg N/ha, seasonal nitrate leaching was 34 to 49% lower with PCU than three applications of urea. Applying urea in five instead of three splits reduced leaching losses to levels similar to those for PCU in 1998 and under excessive irrigation in 1999, but resulted in 38% higher leaching losses compared to PCU in the standard irrigation experiment in 1999. Recovery of applied N at the 280 kg N/ha rate ranged from 25 to 70% and was higher with PCU (mean 56%) than urea (mean 44%). Increasing urea applications to five did not improve N recovery compared to three applications and still resulted in lower recovery (mean 44%) compared to PCU. Results from this study indicate that PCU can reduce leaching and improve recovery of N in potato production, particularly under leaching conditions.