Pasture grass and legume evaluation on seasonally waterlogged and seasonally dry soils in north-east Thailand

Abstract Tropical pasture grasses and pasture legumes were evaluated for seasonally wet and seasonally dry lowland pastures (1500 mm average annual rainfall) on infertile soils in north-east Thailand. The best grass was Paspalum atratum (BRA009610) which produced on average, more than 20 t/ha DM in a 6-month wet season. This grass has been released in Thailand as cv. Ubon. Setaria sphacelata var. sericea cv. Splenda and Paspalum plicatulum grew well but were less productive than P. atratum . Brachiaria decumbens grew well on drier sites, particularly during the dry season when it produced over 10 t/ha DM in 6 months. Brachiaria ruziziensis was very productive in the first season but productivity declined in following years on waterlogged soils which dried out rapidly in the dry season. Digitaria milanjiana cv. Jarra was slow to establish but was very productive in the third year on well-drained soils, producing over 27 t/ha DM in the wet season. Stylosanthes guianensis cv. Graham and S. hamata cv. Verano were the best legumes followed by Calopogonium mucunoides , but they failed to grow in the second dry season. Macroptilium gracile cv. Maldonado grew well in the wet season following planting, but it did not persist. On seasonally wet waterlogged and seasonally dry soils, P. atratum appears the best grass to recommend for smallholder dairy farmers but no legumes performed well enough to be recommended at this stage