Efficacy of woody biomass and biochar for alleviating heavy metal bioavailability in serpentine soil.
Crops grown in metal-rich serpentine soils are vulnerable to phytotoxicity. In this study, Gliricidia sepium (Jacq.) biomass and woody biochar were examined as amendments on heavy metal immobilization in a serpentine soil. Woody biochar was produced by slow pyrolysis of Gliricidia sepium (Jacq.) biomass at 300 and 500 °C. A pot experiment was conducted for 6 weeks with tomato (Lycopersicon esculentum L.) at biochar application rates of 0, 22, 55 and 110 t ha-1. The CaCl2and sequential extractions were adopted to assess metal bioavailability and fractionation. Six weeks after germination, plants cultivated on the control could not survive, while all the plants were grown normally on the soils amended with biochars. The most effective treatment for metal immobilization was BC500-110 as indicated by the immobilization efficiencies for Ni, Mn and Cr that were 68, 92 and 42 %, respectively, compared to the control. Biochar produced at 500 °C and at high application rates immobilized heavy metals significantly. Improvements in plant growth in biochar-amended soil were related to decreasing in metal toxicity as a consequence of metal immobilization through strong sorption due to high surface area and functional groups.
Chemical and Environmental Systems Modeling Research Group, National Institute of Fundamental Studies, Kandy, 20000, Sri Lanka.
Tharanga
T
Bandara
Chemical and Environmental Systems Modeling Research Group, National Institute of Fundamental Studies, Kandy, 20000, Sri Lanka.
Indika
I
Herath
Chemical and Environmental Systems Modeling Research Group, National Institute of Fundamental Studies, Kandy, 20000, Sri Lanka.
Prasanna
P
Kumarathilaka
Department of Agricultural Chemistry, National Taiwan University, Taipei, 106, Taiwan.
Zeng-Yei
ZY
Hseu
Korea Biochar Research Center, Department of Biological Environment, Kangwon National University, Chuncheon, 24341, Korea.
Yong Sik
YS
Ok
Chemical and Environmental Systems Modeling Research Group, National Institute of Fundamental Studies, Kandy, 20000, Sri Lanka. meththikavithanage@gmail.com.
Meththika
M
Vithanage
D001682:Biological Availability; D018533:Biomass; D002122:Calcium Chloride / Q000737:chemistry; D002606:Charcoal; D005591:Chemical Fractionation; D052918:Environmental Restoration and Remediation / Q000379:methods*; D007887:Fabaceae; D018525:Germination; D018551:Solanum lycopersicum / Q000254:growth & development; D019216:Metals, Heavy / Q000032:analysis / Q000493:pharmacokinetics* / Q000633:toxicity; D012989:Soil Pollutants / Q000032:analysis / Q000493:pharmacokinetics* / Q000633:toxicity; D013188:Sri Lanka; D013696:Temperature
D019216:Metals, Heavy; D012989:Soil Pollutants; C540010:biochar; D002606:Charcoal; D002122:Calcium Chloride
Black carbon; Ca/Mg ratio; Charcoal; Chemical stabilization; Soil amendment