Agricultural Research Centre, Trangie, N.S.W. 2823
Fifteen tropical and subtropical grasses and five tropical legumes were grown in pure swards under rainfed or irrigated (two frequencies) conditions on an alkaline brown clay soil at Trangie in western New South Wales. They were cut every six weeks during the growing season, which extended from October to April.
The highest annual dry matter yield under irrigation (16.7 t ha-1) was produced by the vegetatively established Setaria sphacelata var. splendida. It reached a peak growth rate of 200 kg ha-1 day-1 in late summer. Panicum coloratum was the highest yielding (13.8 t ha-1) grass established from seed; Paspalum dilatatum produced 13.0 t ha-1. P. coloratum was the highest yielding grass under rainfed conditions where it yielded 1.7 t ha-1. Flood irrigation at the pan evaporation interval of 50 mm compared to 100 mm made no difference to forage yields.
The tropical grasses, including Brachiaria decumbens and Paspalum plicatulum, failed to survive the winter. The legumes recovered poorly after winter and were not recommended for this environment. Narok setaria, kikuyu and Paspalum nicorae were quite tolerant of low winter temperatures but lacked vigour in the summer, yielding less than 10 t ha-1.