Abstract: | Abstract The relation between Mo concentration of several tropical pasture legumes and their growth response to Mo application has been compared. Lotononis had the greatest ability to take up Mo and its growth was least responsive to Mo application. There were no consistent differences between Mo concentrations in Siratro, desmodium and glycine, even though their growth responses differed. The concentrations of Mo in plant shoots required for maximum growth were about 0.02 ppm or less for all species. By contrast, critical Mo concentrations in shoots of temperate pasture legumes usually exceed 0.1 ppm. When Mo was annually applied to soil on which no growth response to Mo occured, Mo concentrations in the shoots of plants reached levels that could be toxic to cattle. |