Improving fertility status of mine tailings for lettuce production using organic and inorganic amendments

Abstract

Restoration of decommissioned Gold Mine Tailings (GMT) is an environmental challenge. In this study, an attempt was made to evaluate the combined application of organic and inorganic amendments' effects on the growth and yield of lettuce in GMT. A Completely Randomized Design (CRD) with three replications was used. For this, a greenhouse pot experiment with eight (8) treatments mixed with tailings collected from Obuasi decommissioned mine site was set up at the CSIR Soil Research Institute. Treatments used were; control, 5 t ha-1 Rice Husk Biochar (RHB), 60 kg N-80 kg P2O5-80 kg K2O (100% NPK), 2.5 t ha-1 RHB + 30 kg N-40 kg P2O5-40 kg K2O (50% NPK), 5 t ha-1 Poultry Litter Compost (PLC), 2.5 t ha-1 PLC + 30 kg N-40 kg P2O5-40 kg K2O (50% NPK), 2.5 t ha-1 RHB + 2.5 t ha-1 PLC and 2.5 t ha-1 RHB + 2.5 t ha-1 PLC + 30 kg N-40 kg P2O5-40 kg K2O (50% NPK). At the end of the study, the highest lettuce yield (433.9 kg ha-1) was found in 2.5 t ha−1 RHB + 50% NPK followed by the 2.5 t ha−1 PLC+ 50% NPK (405.4 kg ha-1). There was no significant difference between them. The lowest yield (144.9 kg ha-1) was recorded in the Control. Again, application of amendments to the GMT showed a significant difference (P<0.05) in pH, organic carbon, total nitrogen content, phosphorus, cation exchange capacity (Ca, Mg, Na and K) of the tailings. The study revealed that the addition of amendments could improve lettuce growth and yield parameters of lettuce and also improve physical and chemical properties of GMT in the semi-deciduous forest zone of Ghana.