Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Proceedings
Publication Acceptance Date: 7/30/2005
Publication Date: 11/1/2005
Citation: Bigelow, C.A., Hardebeck, G., Walker, K., Smith, D.R. 2005. Kentucky bluegrass response to three autumn applied urea sources. In: Proceedings of the ASA-CSSA-SSSA Annual Meeting Abstracts, November 6-10, 2005, Salt Lake City, UT. 2005 CDROM.
Technical Abstract: Nitrogen (N) is the nutrient required in the greatest abundance to produce a dark green, dense turf. Moderate to high quality Kentucky bluegrass lawns in the cool-humid region require 98-196 kg N ha-1 yr-1 to sustain quality with the majority of N applied in the autumn months. For homeowners, providing a consistent N supply using inexpensive soluble N sources, like urea, is difficult due to their lack of commitment to regular fertilization. Thus, malnourished, low density, weed and disease prone lawns often result. Infrequent relatively high application rates of coated urea products like sulfur-coated urea (SCU) or polymer coated urea (PCU) may be a feasible alternative practice to ensure adequate N is available to promote a healthy vigorous turf through the autumn months. This two-year field study evaluated various application frequencies of urea, SCU and PCU when applied either in one single, 147 kg N ha-1 application the first week of Sept. or three monthly 49 kg N ha-1 applications over the autumn months to an irrigated lawn turf. Dry matter yield (DMY), greenness and visual turf quality (TQ) varied with N source, N application rate and season. DMY, however, generally followed a typical cool-season growth curve and as expected DMY and greenness increased with N application rate. Compared to urea alone, the single applications of SCU or PCU provided a more consistent appearance and color. Soil N was determined via KCl extraction at two depths; 0-15 and 15-30 cm, in Dec. year one, and three autumn dates in year two and showed little appreciable N loss due to any urea source or N rate. Therefore, a single relatively heavy, 147 kg N ha-1, application of SCU or PCU in early Sept. may be an effective alternative fertilization strategy for homeowners desiring a high quality lawn which requires less effort.