Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS), CSIC, Avenida Reina Mercedes 10, Sevilla, Spain.
Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Brno, Czech Republic.
Pest Manag Sci. 2021 Feb;77(2):834-843. doi: 10.1002/ps.6086. Epub 2020 Sep 24.
Allelochemicals can act as biopesticides or enhance the action of synthetic pesticides. In this work, we assessed the bioavailability of the allelochemical coumarin in soils amended with fresh or field-aged biochars (BCs). The fresh BC from oak wood (Fresh BC) was prepared at 550 °C and was buried for aging in two different places: in a sandy loam soil in Spain for 15 months (Aged BC_1) and a sandy loam soil in USA for six months (Aged BC_2).
Sorption experiments showed that all BCs were able to increase the affinity of soil towards coumarin, with the distribution coefficient following the order: unamended soil < Aged BC_2-amended soil < Aged BC_1-amended soil < Fresh BC-amended soil. All biochars ensure greater persistence of coumarin and the effect was more pronounced at high chemical dose (10 mg kg ). Conversely, leaching studies in soil columns revealed that BCs were able to maintain coumarin within the first 5 cm of top-soil with total amount extracted ranging between 17% and 22% for BC-amended soil and <1% for unamended soil. Leaching was only observed when coumarin was added at the highest rate. Likewise, the bioefficacy of coumarin against lettuce was enhanced only at 10 kg ha with BC-amended soil.
Biochar application to agricultural soils is a promising tool for the management of natural compounds with potential use as biopesticides, such as coumarin, because it increases sorption, persistence and, in some cases, bioefficacy. The results reveal that this effect still persists with aging of BC in soils.
化感化合物可以作为生物农药，或增强合成农药的作用。在这项工作中，我们评估了新鲜或田间老化生物炭（BC）添加的土壤中化感物质香豆素的生物有效性。从橡木中制备的新鲜 BC（Fresh BC）在 550°C 下制备，并在两个不同的地方进行老化埋藏：在西班牙的砂壤土中进行 15 个月（Aged BC_1）和在美国的砂壤土中进行六个月（Aged BC_2）。
吸附实验表明，所有 BC 都能够增加土壤对香豆素的亲和力，分配系数的顺序为：未添加土壤< aged BC_2 土壤< aged BC_1 土壤< fresh BC 土壤。所有生物炭都确保了香豆素具有更大的持久性，并且在高化学剂量（10mgkg）下效果更为明显。相反，在土壤柱中的淋溶研究表明，BC 能够将香豆素保持在表层土壤的前 5cm 内，从添加 BC 的土壤中提取的总量在 17%至 22%之间，而未添加的土壤则<1%。只有当香豆素以最高速率添加时才会发生淋溶。同样，只有在添加 BC 的土壤中，香豆素对生菜的生物功效仅在 10kg ha 时才会增强。
将生物炭应用于农业土壤是管理具有生物农药潜力的天然化合物（如香豆素）的有前途的工具，因为它增加了吸附、持久性，并且在某些情况下还增加了生物功效。结果表明，随着 BC 在土壤中的老化，这种效果仍然存在。
