Testing of Controlled Release Fertilizer Programs for Seep Irrigated Irish Potato Production

Abstract A Best Management Practices (BMP) program has been implemented for Northeast Florida potato (Solanum tuberosum) producers to reduce the potential for nitrate (NO3) leaching from the 9000 ha of land in potato production in the St. Johns River watershed. Controlled release fertilizers (CRFs) could supply nutrients to potatoes while reducing the potential for off‐site movement of nutrients thus, providing a long‐term solution to the problem of NO3 leaching on sandy soils. The objectives of this project were to evaluate the quality and quantity of potatoes fertilized with CRFs and soluble fertilizers and to determine the influence of nitrogen (N) source on N use efficiency (NUE). Fertilizer treatments were: (a) no N control; (b) ammonium nitrate (AN) and urea; (c) polymer coated urea (PCU) and polymer sulfur coated urea (PSCU); (d) polymer coated 11‐11‐11 product; and (e) polymer coated 15‐9‐12 product. Fertilizers treatments were each applied 112, 168, and 224 kg ha−1. The highest total and marketab...