EFFECT OF PHOSPHORUS ON GROWTH AND CHEMICAL COMPOSITION OF SOME TROPICAL PASTURE LEGUMES .I. GROWTH AND CRITICAL PERCENTAGES OF PHOSPHORUS

Nine tropical and one temperate pasture legume species were grown in pots ofsoil with varying additions of phosphate. Growth responses and chemical conlpositionof the plant tops were recorded, and from the latter, critical percentages of phosphoruswere established. These were verified by using data from two soils in the pot cultureinvestigation and a total of six field sites. Glycine javanica and Desmodium intortum were the most responsive species inpots, and Stylosanthes humilis and Lotononis bainesii were the least responsive species. The quantity of phosphorus per pot accumulated in the tops of the plants was greatestfor Stylosanthes humilis and Lotononis bainesii at all treatment levels. Critical percentagesof phosphorus in the tops of Phaseolus Iathyroides, Phaseolus atvopuvpureus, Stylosantheshumilis, Centrosema pubescens, Glycine javanica, Lotononis bainesii, Medicago sativa, Desmodium uncinatum, DesmorEium intortum, and Vigiza luteola sampled at theimmediate pre-flowering stage of growth were 0.20, 0.24, O. 17, O. 16, 0.23, O. 17, 0.24, 0.23, 0.22, and 0.25% phosphorus respectively. © 1969 CSIRO. All rights reserved.