title: Conocarpus biochar as a soil amendment for reducing heavy metal availability and uptake by maize plants.
abstract: The objective of this study was to assess the use of Concarpus biochar as a soil amendment for reducing heavy metal accessibility and uptake by maize plants (Zea mays L.). The impacts of biochar rates (0.0, 1.0, 3.0, and 5.0% w/w) and two soil moisture levels (75% and 100% of field capacity, FC) on immobilization and availability of Fe, Mn, Zn, Cd, Cu and Pb to maize plants as well as its application effects on soil pH, EC, bulk density, and moisture content were evaluated using heavy metal-contaminated soil collected from mining area. The biochar addition significantly decreased the bulk density and increased moisture content of soil. Applying biochar significantly reduced NH4OAc- or AB-DTPA-extractable heavy metal concentrations of soils, indicating metal immobilization. Conocarpus biochar increased shoot dry biomass of maize plants by 54.5-102% at 75% FC and 133-266% at 100% FC. Moreover, applying biochar significantly reduced shoot heavy metal concentrations in maize plants (except for Fe at 75% FC) in response to increasing application rates, with a highest decrease of 51.3% and 60.5% for Mn, 28% and 21.2% for Zn, 60% and 29.5% for Cu, 53.2% and 47.2% for Cd at soil moisture levels of 75% FC and 100% FC, respectively. The results suggest that biochar may be effectively used as a soil amendment for heavy metal immobilization and in reducing its phytotoxicity.
authors.affiliation: Department of Soil Sciences, Saudi Biochar Research Group, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia.
authors.forename: Mohammad I
authors.initials: MI
authors.lastname: Al-Wabel
authors.affiliation: Department of Soil Sciences, Saudi Biochar Research Group, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia ; Department of Soils and Water, Faculty of Agriculture, Assiut University, Assiut 71526, Egypt.
authors.forename: Adel R A
authors.initials: AR
authors.lastname: Usman
authors.affiliation: Department of Soil Sciences, Saudi Biochar Research Group, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia ; Department of Soil Science, Faculty of Agriculture, Ain Shams University, 68 Hadayek Shobra, P.O. Box 11241, Cairo, Egypt.
authors.forename: Ahmed H
authors.initials: AH
authors.lastname: El-Naggar
authors.affiliation: Department of Soil Sciences, Saudi Biochar Research Group, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia ; Soil and Water Science Dept., Alexandria University, Egypt.
authors.forename: Anwar A
authors.initials: AA
authors.lastname: Aly
authors.affiliation: Department of Soil Sciences, Saudi Biochar Research Group, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia ; Department of Soil and Water, Suez Canal University, Ismailia 41522, Egypt.
authors.forename: Hesham M
authors.initials: HM
authors.lastname: Ibrahim
authors.affiliation: Department of Soil Sciences, Saudi Biochar Research Group, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia.
authors.forename: Salem
authors.initials: S
authors.lastname: Elmaghraby
authors.affiliation: Department of Soil Sciences, Saudi Biochar Research Group, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia.
authors.forename: Abdulrasoul
authors.initials: A
authors.lastname: Al-Omran
keywords: Biochar; Bulk density; Heavy metal accessibility; Heavy metal immobilization; Moisture content; Zea mays