Field and laboratory trials were conducted to assess the effect of quarry dust amendments media on plant growth (biomass) of various selected tree species for re-vegetation purposes of quarry sites in Ndurugu, Kiambu-Kenya. A randomized complete block design experiment was piloted with two-month-old nursery established seedlings of four tree species (Acacia abyssinica, Casuarina equisetifolia, Eucalyptus grandis, and Schinus molle) planted in four different media treatments. The media treatments were quarry dust (QD), and quarry dust amendments of a combination of quarry dust with red soil (QD+RS), with manure (QD+MN), and with forest soil (QD+FS), in a ratio of 2:1. Destructive sampling was done in three phases after the third, sixth, and ninth months of transplanting. Measurements for tree height, fresh and dry weights were done bi-weekly in the field and laboratory. Analysis of variance (ANOVA) was conducted, and results showed a substantial difference in time-species interaction on belowground, aboveground biomass, and root shoot ratio, at p ≤ 0.05. Generally, the results obtained from the research study point out that quarry dust-manure combination has the prospective to influence the growth of the plant species favorably. The medium can be recommended for the re-vegetation process in quarry sites in Ndarugu, Kenya.
Keywords: elite trees, quarry dust, plant biomass, re-vegetation, root shoot ratio