Biomass Production and Nutrient Accumulation by Natural Rubber (Hevea brasiliensis Wild. Ex A. Juss.) Müell. Arg. Clones in a Humid Tropical Area in South India

Abstract

Natural rubber (Hevea brasiliensis Wild. Ex A. Juss.) Müell. Arg. is an important commodity crop grown in world over for industrial raw material rubber latex for various products, mainly tyre manufacturing. Hevea propagation is through clones evolved by breeding as cultivars with desired characters. This article presented the biomass and nutrient accumulation of four important Hevea clones viz. RRII 105, RRII 118, RRII 203 and GT1 at 30 years age. Biomass and nutrient concentration of tree components viz. trunk, branches, leaf and root were assessed by uprooting the trees in the field and standing trees using allometric equation. Among the different clones, RRII 118 and GT1 recorded higher biomass compared to RRII 105 and RRII 203. Above-ground biomass (88-93 per cent) varied more than below-ground biomass (7-11 per cent). The high yielding clones had higher leaf and root biomass. Drought tolerant and timber clones viz. RRII 118 and RRII 203 recorded higher K and high yielding clone RRII 105 had higher Ca accumulation. Biomass removal of these clones may lead to deficiency of K and Ca in soil and hence needs the external supplements. The relation of high Ca content and leaf disease of fungal origin is promising for further studies. The higher accumulation of iron and manganese indicated the tolerance of Hevea to these elements and possibility of phytoremediation. The per cent contribution of nutrients to total biomass varied less between clones and was below 3 percent at the age of 30 years and this is evidence of adjustments in proportions of nutrients in Hevea irrespective of clonal variations.