Volume 37, 20-32

Tropical Grasslands (2003) Volume 37, 20–32

Evaluation of forage legumes and grasses on seasonally waterlogged sites in north-east Thailand

M.D. HARE, C. KAEWKUNYA, P. TATSAPONG and M. SAENGKHAM

Faculty of Agriculture, Ubon Ratchathani University, Ubon Ratchathani, Thailand

Abstract

Seven legumes sown in pure swards and 7 grasses sown with legumes and fertilised with N were evaluated in a series of trials at 7 low lying infertile sites in north-east Thailand over 2–3 years from 1997–2000. All sites have an average annual rainfall of 1400 mm.
The highest legume yield in pure swards was in the year of sowing from Aeschynomene americana cv. Lee, which produced over 14 t/ha DM at one site. All legumes failed to persist beyond the second wet season under cutting. Stylosanthes guianensis cv. Tha Phra (CIAT 184) showed some promise as a legume at some sites that were not deeply waterlogged but only in a few places was it able to persist into the second dry season. No legumes performed well enough to be recommended for such sites under the existing management system.
The best grasses on deeply waterlogged sites were Paspalum atratum cv. Ubon, P. plicatulum (common Thailand type) and Setaria sphacelata var. splendida cv. Splenda. These 3 grasses performed well at all sites and were the most consistent in terms of persistence and yield. On less waterlogged sites, Panicum maximum cv. Purple was very productive, producing in excess of 30 t/ha DM in the second 6-month wet season at 2 sites. Brachiaria ruziziensis (common Thailand type), B. decumbens cv. Basilisk, and Digitaria milanjiana cv. Jarra grew well only on sites that did not become inundated with water. No legumes were able to persist in the nitrogen-fertilised (100–120 kg/ha N) grass swards beyond the second wet season.