A.C. ANDREWS1 and T.A. GIBSON2
Thai Australian Highland Agricultural Project
University of Chiang Mai Thailand
1Department of Agronomy and Soil Science, University of New England, Armidale. N.S.W. 2351 Australia.
2Faculty of Agriculture, University of Khon Kaen, Thailand.
A series of cutting trials were used to evaluate 19 legume and 13 grass cultivars in pure swards or legume–grass mixtures, and with and without fertiliser containing phosphorus and sulphur. Trials were carried out on a limestone soil at an elevation of 800 m in the highlands of Northern Thailand.
Desmodium intortum and Stylosanthes guianensis gave the highest yields; the former was more persistent and outyielded others in the third year. Highest grass yields were obtained from Brachiaria decumbens, Panicum maximum (cv. Hamil) and Setaria sphacelata. Good persistence and higher protein content, but lower dry matter production, were recorded by Centrosema pubescens, Leucaena leucocephala and Paspalum dilatatum. Changes in species performance with altitude were related to known responses to temperature.
Fertiliser increased the growth of legumes by 200% and grasses by 45% in the first year but had no significant effect in subsequent years. Protein levels of legumes were double, those of grasses but phosphorus contents were similar. Mixed legume-Nandi setaria swards changed from legume dominance to grass dominance within two years.