School of Energy Science and Engineering, Central South University, Changsha, Hunan 410083, China; College of Land Science and Technology, China Agricultural University, Beijing 100193, China.
School of Agriculture, Yunnan University, Kunming, Yunnan 650500, China.
Sci Total Environ. 2024 Dec 1;954:176531. doi: 10.1016/j.scitotenv.2024.176531. Epub 2024 Sep 25.
The effects of engineered steam exploded biochar on the phytoavailability of toxic elements in the shared- and nonshared-rhizosphere of vegetable-grass intercropping system have not been investigated yet. Therefore, we explored and elucidated the synergistic effect of pristine rape-straw biochar (BC), steam exploded BC (BCSE), KMnO-modified BCSE (BCSEMn), and hydroxyapatite-modified BCSE (BCSEHA) on the solubility, fractionation and phytoavailability of lead (Pb) in a vegetable-grass intercropping system. In a rhizosphere box, Brassica chinensis L. (pakchoi; PC, as a vegetable) and Pennisetum polystachion L. (mission grass; MG, as a Pb hyperaccumulator), were grown in the biochar treated soil with (non-shared rhizosphere) or without (shared rhizosphere) root separation. Addition of BCSEMn and BCSEHA, particularly BCSEMn, significantly improved plant growth, photosynthetic pigment levels, and positively influenced the gas exchange attributes by suppressing oxidative stress and boosting antioxidant enzymes activities. Both biochars altered a proportion of Pb in the acid soluble to the immobile fraction and thus significantly decreased its leachability (TCLP-Pb) and bioavailability (CaCl-extrcated Pb) by 32.7 %-33.9 % and 48.5 %-53.5 %, respectively, as compared to the control. Both biochars, particularly BCSEMn, reduced significantly the Pb content in shoots and roots of PC and MG with a significantly higher efficiency in the PC than in the MG; this was the case more in the shared than in the non-shared rhizosphere. These findings indicate the synergistic effect of BCSEMn and BCSEHA and intercropping for enhancing the grass phytostabilization capacity for Pb and reducing its uptake by edible plants in a vegetables-grass system, which could be used as a promising approach for the phytomanagement of Pb contaminated soils.
尚未研究工程蒸汽爆炸生物炭对蔬菜-草间作系统共享和非共享根际中有毒元素的植物可利用性的影响。因此，我们探索并阐明了原始油菜秸秆生物炭（BC）、蒸汽爆炸生物炭（BCSE）、KMnO 改性 BCSE（BCSEMn）和羟基磷灰石改性 BCSE（BCSEHA）对蔬菜-草间作系统中铅（Pb）的溶解度、形态和植物可利用性的协同作用。在根际箱中，白菜（B. chinensis L.，作为蔬菜）和象草（P. polystachion L.，作为 Pb 超积累植物）在有（非共享根际）或没有（共享根际）根分离的生物炭处理土壤中生长。添加 BCSEMn 和 BCSEHA，特别是 BCSEMn，显著改善了植物生长、光合色素水平，并通过抑制氧化应激和提高抗氧化酶活性，对气体交换特性产生了积极影响。两种生物炭都改变了一部分可溶态 Pb 为不可移动态，从而使 Pb 的浸出率（TCLP-Pb）和生物可利用率（CaCl 提取 Pb）分别降低了 32.7%-33.9%和 48.5%-53.5%，与对照相比。与对照相比，两种生物炭，特别是 BCSEMn，显著降低了 PC 和 MG 地上部和根部的 Pb 含量，在 PC 中的效率明显高于 MG；在共享根际中比在非共享根际中更为明显。这些发现表明，BCSEMn 和 BCSEHA 的协同作用以及间作对提高草对 Pb 的植物稳定化能力和降低其在蔬菜-草系统中可食植物的吸收具有重要意义，这可能是一种有前途的 Pb 污染土壤植物管理方法。
