Faculty of Environment, University of Jan Evangelista Purkyne, Kralova Vysina 3132/7, Usti nad Labem, 400 96, Czech Republic; Laboratoire Génie Civil et géo-Environnement (LGCgE), ISA Lille, Yncréa Hauts-de-France, 48 Boulevard Vauban, 59046, Lille Cedex, France.
ECOLAB, Université de Toulouse, CNRS, INPT, UPS - ENSAT, Avenue de l'Agrobiopôle, F-31326, Castanet-Tolosan, France.
Ecotoxicol Environ Saf. 2020 Aug;199:110654. doi: 10.1016/j.ecoenv.2020.110654. Epub 2020 May 11.
Miscanthus x giganteus is suggested as a good candidate for phytostabilization of metal-polluted soils. Its late harvest in winter generates large amounts of leaf litter on the soil surface. However, little is known about the mobility and the bioavailability of metals following leaf decomposition and the consequences on the succeeding culture. Ex situ artificial aging for 1, 3, and 6 months was conducted with miscanthus leaf fragments incorporated into three agricultural soils displaying a gradient concentration in Cd (0.6, 3.1 and 7.9 mg kg), Pb (32.0, 194.6 and 468.6 mg kg), and Zn (48.4, 276.3 and 490.2 mg kg) to simulate the leaf litter input over 20 years of miscanthus culture. We investigated the impacts on physicochemical and biological soil parameters, CaCl-extractable metal, and their subsequent ryegrass shoot concentrations, and hence on ryegrass health. The results showed that the amended soils possessed higher pH along with greater available phosphorous and soil organic carbon values. The respiratory activity and microbial biomass carbon in the amended soils increased mainly after 1 month of aging, and decreased afterwards. Despite the higher Pb- and Zn-CaCl extractability in the amended soils, the phytoavailability slightly increased only in the most contaminated soils. Moreover, leaf incorporation did not affect the ryegrass biomass, photosynthetic pigment contents, nor the antioxidative enzyme activities. Conclusively, leaf incorporation induced slight variations in soil physicochemical and biological parameters, as well as metal extractability, but not to an extent that might cause a considerable threat to the subsequent culture. Nevertheless, these results are preliminary data that require confirmation by long-term in-situ experimentations as they reflect the modelization of long-term impact of leaf decomposition on soil-plant system.
荻（Miscanthus x giganteus）被认为是用于稳定受金属污染土壤的一种良好候选植物。其在冬季晚收获，会在土壤表面产生大量的叶片凋落物。然而，对于叶片分解后金属的迁移性和生物可利用性以及对后续作物的影响，我们知之甚少。本研究通过将荻叶片碎片与三种农业土壤混合，进行了 1、3 和 6 个月的离体人工老化实验，这些土壤中 Cd（0.6、3.1 和 7.9mg/kg）、Pb（32.0、194.6 和 468.6mg/kg）和 Zn（48.4、276.3 和 490.2mg/kg）的浓度呈梯度分布，以模拟 20 多年荻栽培过程中叶片凋落物的输入。我们研究了这些处理对土壤理化和生物学参数、CaCl 提取态金属以及随后黑麦草地上部浓度的影响，从而评估了对黑麦草健康的影响。结果表明，添加的土壤具有更高的 pH 值和更高的有效磷和土壤有机碳含量。添加土壤的呼吸活性和微生物生物量碳在老化 1 个月后主要增加，随后减少。尽管添加土壤中 Pb 和 Zn 的 CaCl 可提取性较高，但只有在污染最严重的土壤中，其植物可利用性才略有增加。此外，叶片添加并未影响黑麦草生物量、光合色素含量或抗氧化酶活性。总之，叶片添加仅导致土壤理化和生物学参数以及金属提取率略有变化，但不会对后续作物造成严重威胁。然而，这些结果是初步数据，需要通过长期原位实验来验证，因为它们反映了叶片分解对土壤-植物系统的长期影响的模型化。
