Resin‐Coated Urea Evaluation for Turfgrass Fertilization

Abstract

AbstractNew resin coatings have been developed for producing slow‐release fertilizers for turfgrasses. It is important that new fertilizer materials be evaluated so that recommendations can be made for their use. Four experimental resin‐coated ureas (RCU) were evaluated for maintenance fertilization of Merion Kentucky bluegrass (Poa pratensis L.) turf grown on an Arkport sandy loam (coarse‐loamy, mixed, mesic Psammentic Hapludalfs). The RCUs had an analysis of 41% N and laboratory release rates of 270 d (RCU‐270), 100 d (RCU‐100), and 70 d (RCU‐70). A mixture of the RCU materials (RCU‐M), sulfur‐coated urea (SCU), urea, a 22–1.8–6.6 with 10% by weight dicyandiamide (DCD), and oxamide were included for comparison. The fertilizers were applied at an annual rate of 196 kg N ha−1, as single‐spring or split‐spring, and fall applications. The most rapid response to fertilization as measured by fresh weight yields and color ratings was produced by urea, followed in order by SCU, RCU‐70, and RCU‐100. The release rate of RCU‐270 was too slow to produce acceptable color ratings through much of the test at both fertilization times. The most uniform response was produced by RCU‐100 at both the single‐spring and split treatments. The highest N recovery in the leaf tissue was obtained from oxamide (24 and 59%), the single‐spring application of SCU (27 and 58%), and the split applications of RCU‐100 (21 and 52%) and RCU‐70 (25 and 54%). Nitrogen recovery from SCU was highest in growth periods immediately following fertilization, while recovery was more uniform across growth periods with the RCU‐100. Certain RCU fertilizers are well suited for turfgrass fertilization.