R.S. KALMBACHER¹, J.E. RECHCIGL¹, F.G. MARTIN², and A.E. KRETSCHMER, Jr³

¹University of Florida, Range Cattle Research and
²Education Centre, Ona, Gainesville, and
³Indian River Research and Education Centre, USA

Abstract

Three experiments were conducted with the perennial pasture grass Paspalum atratum cv. Suerte at Ona, Florida. In Experiment I, Suerte was evaluated in 1992–1993 on a Pomona fine sand for responses to dolomite (0, 1.1, 2.2, 3.4, 4.5 and 6.7 t/ha) and broadcast-sowing rates (5.6, 13.6 and 20.5 kg/ha pure, live seed [PLS]). Dolomite increased soil pH (4.5 + 0.22X, X = t/ha), Suerte density (plants/m² = 32.7 + 7.3X - 0.99X²) and mean 42-d forage yield (kg/ha = 2904 + 248.0X - 25.1X²). Dolomite did not affect crude protein (6.1%), but did increase IVOMD (% = 53.6 + 0.65X). A target pH for Suerte should be about 5.0, which was achievable with about 3.0 t/ha dolomite on this sandy Florida soil. Initially, density increased with increasing sowing rate (plants/m² = 18.6 + 1.7X, X = > 5.6 kg/ ha PLS), but there was no difference in density after 2.5 years (33 plants/m²).
In Experiment II, Suerte was broadcast-sown at 1.5, 3.0, 4.5 and 6.0 kg/ha PLS on March 1, May 1, July 1 and September 1, 1995. Average density in the 84-d period after sowing from March and May increased with increasing sowing rates (plants/m² = 11.3 + 2.3X, X = > 1.5 kg/ha PLS), whereas July and September sowings failed due to flooded soil. Mean yield in June and July 1996 from March and May 1995 sowings increased with increasing sowing rate (kg/ha = 1200 + 240X). When broadcast, seed should be sown at 5–6 kg/ha PLS.
In Experiment III, Suerte seed was flooded for 0, 2, 4, 6, 8, 10, 14, 21 and 28 d, drained, and incubated for 28 d. Suerte seed lost about 2% germination for each day it was flooded.