Remediation of soil arsenic toxicity in Ipomoea aquatica, using various sources of organic matter

摘要

Various sources of organic matter (namely poultry litter, cow dung and sewage sludge) were used to remediate arsenic accumulation in plants {Ipomoea aquatica) in a pot-culture experiment. Organic matter was applied at the rates of 5 t/ha and 10 t/ha to soils spiked with arsenite at 20, 50 and 100 mg As/kg soil. Plants were grown for 30 days after germination. The presence of arsenic in the growth medium had a negative impact on the vegetative growth of the plants, for both organic matter treatments and control. However, organic-matter application had a more positive effect than no application, at all levels of arsenic spiking. Poultry litter performed the best, and at the application rate of 5 t/ha, the vegetative growth was more than 81.55% over the control; whereas the increases were 17.74% and 10.98%, respectively, for cow dung and sewage sludge at the same rate of application. Organic-matter application was able to reduce arsenic accumulation by as much as 75% in the vegetative part of the plant. For the various sources of organic matter, the performance in reducing the accumulation of As in Ipomoea aquatica followed the order: poultry litter > cow dung > sewage sludge.