Effect of lime, potassium, sulfur and micronutrients on the growth of Centrosema pubescens in acid soil

Abstract

An experiment was undertaken in a glasshouse to study the effect of lime, K, S, Zn, Cu, B and Mo, at two levels, on the growth nodulation and nitrogen fixation of Centrosema pubescens Benth in a Red-Yellow Latosol. Rates of lime and nutrients in kg.ha^-1 were: lime, o and 4,000; K, 0 and 100; S, 0 and 30; Zn, 0 and 4.5; Cu, 0 and 2.5; B, 0 and 1.0; Mo, 0 and 0.38. Liming had a large effect in increasing dry weight of tops and roots, nodule number and dry weight and N concentration in the tops. There was a significant lime x K interaction, so that in the absence of lime, K depressed root dry weight, but in the presence of lime, K increased nodule number and dry weight. Molybdenum increased symbiotic N₂ fixation. Results suggest that centrosema would respond to Zn, especially in the presence of lime. The application of S, Cu and B had no effect on the centrosema growth or symbiotic N₂ fixation.