Response of Turfgrass to Various Nitrogen Sources

Abstract

Nitrogen sources with different properties and release characteristics are used to meet a variety of fertility management needs in turfgrass culture. Our objective was to determine the response of turfgrass to various urea‐formaldehyde reaction products; two particle sizes of oxamide; experimental sulfur‐coated ureas (SCU); products containing combinations of N sources; and an experimental composted sewage sludge. Nitrogen sources included for comparative purposes were isobutylidene diurea (IBDU); commercial SCU products; soluble sources; and Milorganite. In this 2.5‐yr study, 25 N source treatments were evaluated on ‘Merion’ Kentucky bluegrass (Poa pratensis L.) using 196 kg N ha−1 yr−1, split into two equal applications. Turf response was measured by weekly color ratings, weekly clipping yields, and N uptake for six growth periods during 2 yr. Urea‐formaldehyde reaction products containing no water‐in‐soluble N (WIN) gave results similar to those of conventional soluble N sources, while products containing WIN caused less initial color and growth responses, but gave a slight residual effect in the third year of use. Nitrogen uptake for powdered ureaform (66% of N as WIN) and the suspension FLUF (20% of N as WIN) was 44 and 75%, respectively, of that obtained with Formolene (0% WIN). Major differences in color and growth were found for the different particle sizes of oxamide, with the fine (<0.25 mm) material providing a faster release and less residual effect than the coarse (1‐3 mm) material. Turf fertilized with coarse oxamide responded similarly to that fertilized with coarse IBDU (0.7‐2.5 mm). Commercial SCU and fine particle SCU made with curtain granulated urea (94% of particles between 1.14 and 2.38 mm; dissolution rates: 6 and 15%) had pronounced residual effects, especially in the spring prior to fertilization. The experimental composted sewage sludge was inferior to Milorganite as a source of N for use on turf. N uptake with the compost treatment was only 32% of that obtained with Milorganite. Turf response from combinations of N sources generally reflected the amount and type of N source present. All N sources except the sludge compost were effective for turfgrass fertilization. Selection of an N source or combination of sources for turf fertilization should be dependent on quickness and duration of response desired, rate and frequency of applications, and various economic factors.

Turfgrass (Cynodon dactylon L.) sod production on sandy soils: I. Effects of irrigation and fertiliser regimes on growth and quality

“…For example, 'activated' sewage sludge has been used successfully for the maintenance of cool-and warm-season turfgrasses (Goatley et al, 1998;Turner and Hummel, 1992). The effectiveness of organic fertilisers depends upon the rate that N becomes available to the plant (Landschoot and Waddington, 1987). Recommended fertiliser types and application rates for the production of turfgrass do not appear to have been reported, but we hypothesise that water-soluble and control-release fertilisers will produce higher quality turfgrass than composted organic fertilisers applied at the same N application rate, due to differences in rates of N release from these fertilisers.…”

Cultural Management and Nitrogen Source Effects on Ultradwarf Bermudagrass Cultivars

“…The main effect of management affected both bermu-in those studies (Landschoot and Waddington, 1987;Moore et al, 1996;Carrow, 1997). Differing results are dagrass and P. trivialis shoot densities (data not shown), but only at 2 (bermudagrass) or 3 (P. trivialis) of 7 likely a function of different fertilizer materials used in the studies, as there is wide diversity in N-release pat-samplings.…”

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

“…This frequent fertilization increases the time, effort, and dedication required to maintain a high quality lawn. Thus, controlled-release N sources, like SCU that do not rely on microbial degradation for N release, have been evaluated for their ability to produce a high quality turf (4,14,15,18,30). The newest group of controlled-release N sources is PCU but response data is limited and direct comparisons to SCU or urea in the same study is generally lacking.…”