Potassium fertilizer studies on Brachiaria mutica/Centrosema pubescens pastures grown on soils derived from coral limestone, Malaita, Solomon Islands. I-Effect of rates of potassium on yield and botanical composition

Abstract

The potassium fertilizer requirements of pastures growing on soils of the Dala Land System were studied over two years at the Dala Research Station. Grass yields increased with increasing rates of K up to the highest rate of 200 kg/ha. In the second year when fertilizer applications ceased, grass yields in the control and low fertilizer treatments were markedly reduced. In both year legume yield was highest with K applied at 100 kg/ha. There may be some advantage in splitting the annual application of fertilizer to maintain a more even potassium content in the herbage and to influence the botanical composition of the pasture. The results indicated that an initial application of K at 75 to 100 kg/ha and subsequent annual maintenance dressings of 25 to 50 kg/ha are required for adequate growth of mixed pasture on these soils.