Late Fall Fertilization of Kentucky Bluegrass

Abstract

Many turfgrass managers apply a portion of the total yearly N to cool‐season turfgrasses in the late fall (November). The purpose of this field study was to compare fertilization programs with and without N applications in November using both slow‐release and soluble N sources. Turfs of two different cultivars of Kentucky bluegrass (Poa pratensis L. cv. Baron and cv. Newport) growing on a Flanagan silt loam (fine, montmorillonitic, mesic Aquic Argiudoll) received 10 fertilization programs utilizing urea, isobutylidene diurea (IBDU), or sulfur‐coated urea (SCU). Urea was applied four times per year with either a spring application or a late‐fall application combined with applications in early June, mid‐July, and early September (171–196 kg N ha−1 yr−1). For IBDU and SCU, application dates and N rates (kg ha−1) consisted of June 98 + September 98, June 98 + November 98, and June 49 + September 49 + November 74. The turfs were rated for color for 3 yr, and clipping weights were determined weekly for the final 2 yr of the study. Results were generally similar for both cultivars, except fewer significant differences in spring color ratings were found on Newport. An application of urea in November, without a subsequent spring fertilization, resulted in higher turf color ratings in the early spring but lower turf color ratings in May and June, compared to turf receiving a spring fertilization. Results indicate that a late‐fall application of urea may not eliminate the need for spring fertilization but may allow a reduction in the amount of N applied in spring. Turfs fertilized with SCU in November received higher color ratings in the spring than did turf fertilized with SCU in September. With IBDU, the June + September program resulted in the highest number of ratings with acceptable turf color. November IBDU applications did not result in higher color ratings in the spring and resulted in inefficient use of the N applied.

Effects of Nitrogen Application Timing on Growth and Quality of a Turfgrass Mixture

“…However, there was no visible sign of injury or winter kill for any treatment during the course of our experiments, probably due to mild winters in the region. These data are in close agreement with findings of several studies conducted in maritime or transitional regions (2,5,7,15,16). On the contrary, SF or F applications in the fall led to improved fall color retention and early spring coloration (Table 3).…”

“…Several studies have compared timing and rates of N application to determine their effects on quality, growth, and development of different turfgrass species (5)(6)(7)(8). Several studies have compared timing and rates of N application to determine their effects on quality, growth, and development of different turfgrass species (5)(6)(7)(8).…”

Single Fall Applications of Coated Urea Fertilizers Produce a High Quality Kentucky Bluegrass Turf

“…Although quality was not recorded in 2006, faster spring green‐up and distinct separation between annual N rates was observed on 17 April. These observations of higher spring and fall quality and improved green‐up from fall‐applied N are all consistent with previous studies (13,16,21,25,32,33) The differences in overall quality were also related to treatment effects on canopy greenness and dollar spot severity.…”

“…To sustain a dark‐green turf and vigor, turfgrass specialists throughout the cool‐humid region have routinely recommend N at 98 to 196 kg/ha/year split into multiple fall applications (7,26,29). The agronomic and physiological benefits of fall‐applied N fertilizers to cool‐season turfgrasses are well documented (11,16,17,19,25,31,32,33,34).…”

Response of a Cool-Season Turf Mixture to Composted Chicken Manure in a Mediterranean Environment

“…These data are in close agreement with the findings of several studies conducted in maritime or transitional regions (Ledeboer and Skogley, 1973;Wehner et al, 1988;Dipaola and Beard, 1992). The lowest temperatures during the 2007-2009 experimental periods were −5.0 • C, −10.4 • C and −8.2 • C each year, and these low temperatures did not injure the turf, even that fertilized with 7.5 g m −2 monthly during fall and winter.…”