Sunday 11 December 2016

Changes on the Phytoavailability of Nutrients in a Mine Soil Reclaimed with Compost and Biochar

Water, Air, & Soil Pollution, 2016, 227:453
DOI: 10.1007/s11270-016-3155-x

Mine soils often contain high levels of metals that produce serious environmental problems and poor fertility conditions that limit their reclamation. The aim of this study was to evaluate the influence of a compost and biochar amendment on the nutrient phytoavailability in a mine soil from the depleted copper mine of Touro (Spain). For this purpose, a greenhouse experiment was carried out amending the mine soil with increasing proportions (20, 40, 80 and 100%) of the compost and biochar mixture and planting Brassica juncea plants. The results revealed that the mine soil had an extremely acid pH and low fertility conditions and was affected by copper contamination. The addition of compost and biochar to the mine soil increased soil pH values (from 2.7 to 8.7), total carbon (from undetectable values to 149 g kg−1) and total nitrogen (from undetectable values to 11,130 mg kg−1) contents and phytoavailable concentrations of K, Mg, Na and P and promoted plant growth, since B. juncea plants did not survive in the untreated mine soil. The application of amendment decreased the phytoavailable concentration of Al, Co, Cu, Fe and Ni in the soil, resulting in a reduction of copper toxicity. The use of compost and biochar as a soil amendment combined with B. juncea plants could be an efficient strategy for the reclamation of degraded soils with low fertility conditions.