Herbaceous biomass yield on an age series of naturally revegetated mine spoils in a dry tropical environment

Abstract

The influence of mine spoils age on herbaceous biomass yield was studied in a dry tropical environment. Natu-rally revegetated mine spoils selected were 1-, 5-, 10-, 15- and 20-year-old. The biomass yield increased with increasing age of the spoils. The root, shoot and total biomass were significantly greater on 5-, 10-, 15- and 20-year- old spoils compared to 1-year-old young spoil. A stabilizing trend in biomass yield started after 10 years, reaching almost a stage of saturation on 20-year-old spoil. Spoil age had affected root/shoot ratio also. However, the root/shoot ratio exhibited a decreasing trend with advance in the age of the spoil. Keywords: Mine spoils, root biomass, root/shoot ratio, shoot biomass, Keywords: SiGe DHBT, Si BJT, quasi-saturation, power dissipation, valenceformer averaging 18.02% and the latter 22.26%. Adults of P. hector utilized nearly 24 floral species as nectar sources, whose sugar concentrations (1258%) corresponded with 1550% in psychophilic flowers. They displayed a hovering habit while harvesting nectar, and frequently contacted the essential organs with probosics and head, thus promoting cross-pollination.