Abstract
Ten pasture species (five grasses and five legumes) were grown in pots in two soils known to be deficient in potassium. Total yield over five harvests was measured for each species with adequate potassium supply (K150, an application rate equivalent to 150 kg K/ha) and under low potassium supply (K0, no applied potassium). The ratio of yield at K0 to that at K150 was determined for each species and it was hypothesized that the higher this value, the greater the ability of the species to extract and utilize low level of potassium. Batiki Blue grass (Ischaemum aristatum) and Desmodium heterophyllum gave the highest K0/K150 value for the grasses and legumes respectively. The success of these two species may partly be attributed to their prostrate habit because, at the fixed cutting height, the amount of K removed in younger tissue would have been lower in these species than in the more erect types.
