Abstract
The influence of controlled release fertilizer programs and application timing on ‘Atlantic’ (Solanum tuberosum L.) production, tuber quality, and water quality were evaluated. Treatments were arranged in a randomized complete block with four replications. Application timing was at fumigation (21 days prior to planting), planting, at hilling (30 days after planting), and a combination of timings. Fertilizer treatments were no N, ammonium nitrate (N at 224 and 280 kg·ha–1), polymer sulfur coated urea, polymer coated urea, and three liquid urea formaldehyde formulations. Controlled release fertilizer N rate was 196 kg·ha–1. Plants fertilized with the ammonium nitrate (N at 224 kg·ha–1) treatment produced the highest total and marketable yield (39.3 and 34.1 MT·ha–1) significantly higher than with the urea formaldehyde treatments. Total and marketable yields from plants fertilized with polymer sulfur coated urea and polymer coated urea treatments were similar to the ammonium nitrate treatments when the majority of N fertilizer was applied at or before planting. No significant difference was found between fertilizer treatments for tuber quality. The 2007 season was relatively dry with limited N leaching pressure, resulting in few observed differences between treatments for nitrate concentration in the root zone or perched water table over the season.
