Abstract
The phosphorus and sulphur fertilizer requirement of over own Stylosanthes humilis and S. hamata were studied over two years on a typical 'upland' soil in northeast Thailand. There was no effect of fertilizer on the initial establishment of both legume species but there was a significant response in yield to 30 kg S/has in both species in both years. Although there was no significant effect of phosphorus on legume yields, there was a trend towards higher yields with increasing rates of P. Glasshouse trials indicated a critical phosphorus concentration in Townsville stylo plant material of 0.15 per cent P, while the critical sulphur concentration was 0.12 per cent. The implications of these results for pasture development in northeast Thailand are discussed.
