Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, No. 1 Shizishan Street, Hongshan District, Wuhan, Hubei, 430070, PR China.
University of Kafrelsheikh, Faculty of Agriculture, Department of Soil and Water Sciences, 33 516, Kafr El-Sheikh, Egypt; University of Wuppertal, School of Architecture and Civil Engineering, Institute of Foundation Engineering, Water- and Waste Management, Laboratory of Soil- and Groundwater-Management, Pauluskirchstraße 7, 42285, Wuppertal, Germany; King Abdulaziz University, Faculty of Meteorology, Environment, and Arid Land Agriculture, Department of Arid Land Agriculture, Jeddah, 21589, Saudi Arabia.
J Environ Manage. 2019 May 1;237:5-14. doi: 10.1016/j.jenvman.2019.02.047. Epub 2019 Feb 16.
Management of toxic elements contaminated upland and wetland soils using biochar is of great concern from both agricultural and environmental points of view. The impact of rice straw- and rapeseed residue-derived biochars produced under 300 °C and 550 °C (added to the soil at 2% and 5%; w/w) on the geochemical fractions, phytoavailability, and uptake of Cu and Pb in a contaminated mining soil under different moisture contents (80%, 60%, and 40% of soil field capacity) was investigated in a greenhouse pot experiment using maize. The higher rate of rice straw-derived biochar pyrolyzed at 550 °C caused a significant reduction in the mobile (soluble + exchangeable) fraction of Cu (59.42%) and Pb (75.4%) and increased the residual fractions of Cu (37.8%) and Pb (54.7%) in the treated soil under the highest moisture content (80%) as compared to the untreated soil. Therefore, this biochar significantly decreased the phytoavailability (CaCl-extractable form) of Cu by 59.5% and Pb by 67.6% under the highest moisture content. Also, at the same moisture level (80%), the higher rate of rapeseed residue-derived biochar pyrolyzed at 550 °C decreased significantly the phytoavailability of Cu by 46.5% and Pb by 60.52% as compared to the untreated soil. The 5% rate of the higher temperature pyrolyzed rice straw and rapeseed biochars decreased the uptake of Cu and Pb by the roots and shoots of maize up to 51% for Cu and 45% for Pb. Immobilization of Cu and Pb in the biochar-treated soil at 80% moisture content may possibly due to the associated increase of soil pH and poorly-crystalline Fe oxides content, and/or the metals precipitation with sulfides. These results indicated that application of high temperature pyrolyzed rice straw- and rapeseed residue-derived biochars at 5% could immobilize Cu and Pb and decrease their uptake by maize under high levels of moisture content; consequently, they can be used for phyto-management of Cu and Pb contaminated wetland soils.
利用生物炭来管理受有毒元素污染的旱地和湿地土壤，从农业和环境角度来看都非常重要。本研究采用温室盆栽试验，以玉米为受试植物，研究了在不同水分含量（土壤田间持水量的 80%、60%和 40%）条件下，添加到受污染矿区土壤中（添加量为 2%和 5%，w/w）的 300°C 和 550°C 下制备的水稻秸秆和油菜籽残渣生物炭（分别记为 RSBC-300 和 RSBC-550、RRBC-300 和 RRBC-550）对土壤中 Cu 和 Pb 的地球化学形态、植物可利用性和吸收的影响。与未处理土壤相比，较高比例的 550°C 热解水稻秸秆生物炭显著降低了高水分含量（80%）下处理土壤中 Cu 的可移动（可溶+可交换）形态（59.42%）和 Pb（75.4%），并增加了 Cu（37.8%）和 Pb（54.7%）的残渣形态。因此，在最高水分含量下，该生物炭显著降低了 Cu 的植物可利用性（CaCl2 可提取态）59.5%，Pb 的植物可利用性降低了 67.6%。同样在 80%的水分水平下，较高比例的 550°C 热解油菜籽残渣生物炭显著降低了 Cu 的植物可利用性 46.5%，Pb 的植物可利用性降低了 60.52%，与未处理土壤相比。在 80%的水分含量下，添加 5%的高温热解水稻秸秆和油菜籽生物炭，可使玉米根和茎叶对 Cu 和 Pb 的吸收量降低 51%（Cu）和 45%（Pb）。在 80%水分含量下，生物炭处理土壤中 Cu 和 Pb 的固定可能是由于土壤 pH 值和非晶态 Fe 氧化物含量的增加，以及/或者金属与硫化物的沉淀。这些结果表明，在高水分含量下，应用 5%的高温热解水稻秸秆和油菜籽残渣生物炭可以固定 Cu 和 Pb，降低玉米对它们的吸收，因此可以用于受 Cu 和 Pb 污染的湿地土壤的植物管理。
