Natural Rubber (Hevea brasiliensis Muell Arg.)

The major commercial source of natural rubber is the rubber tree (Hevea brasiliensis). Cultivation of NR tree is mainly confined to the regions experiencing warm humid equatorial monsoon climate. Thailand, Indonesia, Vietnam, Malaysia and India are the major natural rubber-producing countries. The soils under NR cultivation in general are acidic in pH and low in nutrients especially Ca and Mg. The soil site suitability criteria for NR cultivation have been developed. The top 0–15 cm layer of the soils under NR cultivation is rich in OC through the turnover of large quantity of organic matter from cover crops, crop residues from the intercrops/cropping system and litter addition from annual leaf fall. Cultivation of NR with leguminous cover crops or carefully designed intercrops suiting the local food habits in the young phase help in the addition of large quantity of crop residues favouring the buildup of soil organic matter, proliferation of microbial community and improvement in soil fertility and soil health. Liming to manage soil acidity and supplementation of Ca and Zn and B recommendations are recent inclusions in the fertility management of NR growing soils in India. Biofertilizers, especially P solubilizers and mobilizers and plant growth-promoting rhizobacteria like Pseudomonas got immense potential for the internal mobilization of nutrients in NR growing soils. Carbon sequestration potential of NR plantations is an added advantage in the global warming scenario. Repeated cycles of NR cultivation in the same soil in the traditional belt of cultivation and expansion of NR cultivation to more and more marginal areas having low soil fertility, in addition to the climatic constraints and uncertainties, warrant careful management of the soil health for sustained production of NR.