Soil Sciences Department, College of Food and Agricultural Sciences, King Saud University, P.O. Box 2460, Riyadh, 11451, Saudi Arabia.
Department of Soils and Water, Faculty of Agriculture, Assiut University, Assiut, 71526, Egypt.
Environ Geochem Health. 2019 Aug;41(4):1705-1722. doi: 10.1007/s10653-017-9955-0. Epub 2017 Apr 19.
A 30-day incubation experiment was conducted using a heavy metal-contaminated mined soil amended with date palm feedstock (FS) and its derivative biochars (BCs) at three pyrolysis temperatures of 300 (BC-300), 500 (BC-500), and 700 °C (BC-700) with different application rates (0.0, 5, 15, and 30 g kg) to investigate their short-term effects on soil respiration (CO-C efflux), microbial biomass carbon (MBC), soil organic carbon (SOC), mobile fraction of heavy metals (Cd, Cu, Pb, Zn, Mn, and Fe), pH, and electrical conductivity (EC). The results showed that FS and BC-300 with increasing addition rate significantly reduced soil pH, whereas SOC, CO-C efflux, and soil MBC were increased compared to the control. On the contrary, BC-500 and BC-700 increased soil pH at early stage of incubation and have small or no effects on SOC, CO-C efflux, and MBC. Based on the results, the date palm biochars exhibited much lower cumulative CO-C efflux than feedstock, even with low-temperature biochar, indicating that BCs have C sequestration potential. Applying BC-700 at 15 and 30 g kg significantly reduced cumulative CO-C efflux by 21.8 and 45.4% compared to the control, respectively. The incorporation of FS into contaminated soil significantly increased the mobile content of Cd and Mn, but decreased the mobile content of Cu. However, BC-300 significantly reduced the mobile content of Cd, Cu, Pb, and Zn. It could be concluded that low-temperature biochar could be used as a soil amendment for reducing heavy metal mobility in mining contaminated soil in addition to minimize soil CO-C efflux.
采用受重金属污染的采矿业土壤，添加椰枣原料（FS）及其衍生生物炭（BC），在 300°C（BC-300）、500°C（BC-500）和 700°C（BC-700）三种热解温度下，设置 0.0、5、15 和 30 g kg -1不同添加率，进行为期 30 天的孵化实验，以研究它们对土壤呼吸（CO 2-C 通量）、微生物生物量碳（MBC）、土壤有机碳（SOC）、重金属的可移动部分（Cd、Cu、Pb、Zn、Mn 和 Fe）、pH 值和电导率（EC）的短期影响。结果表明，FS 和添加率增加的 BC-300 显著降低了土壤 pH 值，而 SOC、CO 2-C 通量和土壤 MBC 与对照相比有所增加。相反，BC-500 和 BC-700 在孵化早期提高了土壤 pH 值，对 SOC、CO 2-C 通量和 MBC 的影响较小或没有影响。根据结果，与原料相比，椰枣生物炭表现出更低的累积 CO 2-C 通量，即使是低温生物炭，表明 BCs 具有碳封存潜力。与对照相比，以 15 和 30 g kg -1的添加率添加 BC-700 可分别显著降低累积 CO 2-C 通量 21.8%和 45.4%。将 FS 掺入受污染土壤中，显著增加了 Cd 和 Mn 的可移动含量，但降低了 Cu 的可移动含量。然而，BC-300 显著降低了 Cd、Cu、Pb 和 Zn 的可移动含量。可以得出结论，低温生物炭可用作改良剂，以减少采矿业污染土壤中重金属的移动性，同时最大限度地减少土壤 CO 2-C 通量。
