Harvest Frequency and Fertilizer Effects on Yield, Quality, and Persistence of Eight Bermudagrasses

Bermudagrass [Cynodon dactylon (L.) Pers.] is a well adapted and widely used forage grass in southern U.S.A. As new cultivars and hybrids are developed there is a need to evaluate and compare their performance to that of the accepted cultivars. This study was initiated to evaluate three established cvs.. Coastal, Coastcross-1, and Midland, two new cvs., Callie (C. nlemfuënsis Vander.) and Tifton 44 and three experimental hybrids designated Tifton 67, 68, and 84. A split-split plot design was used to evaluate harvest frequency and fertilizer levels on performance of the grasses on a Plinthic Paleudult soil. The grasses were main plots, N fertilizer rates of 336 and 672 kg/ha were subplots and harvest frequencies of 1, 2, 4, and 8 weeks were sub-subplots. Data were gathered on forage yield, in vitro dry matter digestibility (IVDMD), crude protein (CP) content, and persistence of the grasses. Dry matter yields were highest in the 1st year for the robust type bermudagrass cvs. Callie, Tifton 67, and Tifton 68. In the 2nd year, Coastal and Tifton 44 were superior due in part to stand losses of the more robust types. Increasing the N rate from 336 to 672 kg/ha significantly (P = 0.05) increased yields, but there were significant interactions with both harvest frequency and genotype. Annual dry matter yields increased with harvest interval except that in the 2nd year there were only small differences among the 1, 2, and 4 week interval. Persistence of the bermudagrasses measured by a single harvest in the spring of the 3rd year ranked Tifton 44, Coastal, and Midland as the top three cultivars under both fertilizer regimes. The other cultivars yielded from 36 to 0.0% of Coastal at the lower N rate and from 57 to 0.0% at the higher rate. These data along with visual observations indicate the superiority of the rhizomatous cvs. (Coastal, Tifton 44, and Midland) in persistence and ability to produce early spring growth.