Effects of Seasonal Nitrogen on Binary Mixtures of Tall Fescue and Bermudagrass

摘要

Using poultry litter responsibly in cool-season/bermudagrass [Cynodon dadylon (L.) Pers.] production systems may require supplemental N fertilization. This study determined if productivity in binary mixtures of tall fescue [Schedonorus arundinaceus (Schreb.)Dumort] and bermudagrass could be improved through applying litter and fertilizer N to coincide with seasonal growth activities. The effects of N timing on dry matter (DM) yield, forage N and P contents, and fescue percent stand were investigated in binary mixtures that comprised two tall fescue cultivars, Flecha MaxQ (summer-dormant) and Jesup MaxQ (summer-active) drill-seeded in 2007 into swards of Russell and Tifton 44 bermudagrass. Three seasonal N treatments were each comprised of 8.6 Mg litter ha(-1) (as-is moisture basis) split into two applications per season with additional 168 kg N ha-1 split into three applications. Based on two spring harvests (April and May), forage DM yield was greater (P 0.01) for October/January treatment that applied N before April than January/March treatment that applied N in January-July (7.0 vs. 3.0 Mg ha(-1), 2 yr averages). Tall fescue stand count in May was greatest in October/January treatment and was greater in Jesup-Tifton 44 than Flecha-Tifton 44 in 2010 (79 vs. 59%). Based on five annual harvests, October/January treatment had the greatest cumulative N uptake of 189 and 182 kg ha(-1) in 2009 and 2010, respectively, and uptake was generally least in Flecha-bermudagrass associations. Results suggest N application timing to favor tall fescue increased the utilization of applied N and P.