Assessment of Seedling Establishment and Growth Performance of iLeucaena leucocephala/i(Lam.) De Wit., iSenna siamea/i(Lam.) and iEucalyptus grandis/iW. Hill ex Maid. in Amended and Untreated Pyrite and Copper Tailings

摘要

Growth and survival performance of Leucaena leucocephala (Lam.) De Wit., Senna siamea Lam. and Eucalyptus grandis W. Hill ex Maid. in amended and untreated pyrite and copper tailings were evaluated under field conditions. The physico-chemical characteristics of the pyrite soil and tailings were determined. Growth in height, basal diameter and later dbh, relative growth rate due to height (RGRh) and basal diameter (RGRd) and survival were determined every after six months. A split block experimental design was used and the data collected were analyzed using a statistical package R, with an additional package lme4. Tailings and pyrite soils had extremely low pH, poor nutritional status, low organic matter content and elevated concentrations of available heavy metals as compared to the unpolluted soils and treated pyrite soil and copper tailings. Growth performance was extremely poor on the untreated pyrite soil and copper tailings for all the species but significantly enhanced by the application of compost and limestone. Treatment had a significant effect on all parameters at all sites. Eucalyptus grandis displayed a higher potential of phytomass accumulation than Leucaena leucocephala and Senna siamea. Even though Leucaena leucocephala grew fastest reaching reproductive maturity in 7 months after planting, relative growth rates of the three species were not significantly different at all sites. The three species can be used for phytostabilisation of the tailings at Kilembe tailings dam sites (KTDS) after treatment while at Low polluted pyrite trail site (LPPTS) and Highly polluted pyrite trail sites (HPPTS) Senna siamea is more suitable as Eucalyptus grandis and Leucaena leucocephala are susceptible to attacks by Syncerus caffer (Buffalos) and Kobus kob thomasi (Uganda Kob).