Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto, 80, 56124 Pisa, Italy.
Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto, 80, 56124 Pisa, Italy; CIRSEC, Centre for Climate Change Impact, University of Pisa, Italy.
Sci Total Environ. 2022 Oct 20;844:157175. doi: 10.1016/j.scitotenv.2022.157175. Epub 2022 Jul 6.
Trees play a pivotal role in the urban environment alleviating the negative impacts of urbanization, and for this reason, local governments have promoted strongly tree planting policies. However, poor soil quality and neglect tree maintenance (e.g., irrigation and fertilization) can seriously mine the plant health status during the tree establishment phase. The use of biochar to provide long-lasting C to the soil and, at the same time, improving soil properties (e.g., improved water holding capacity), soil enzymes activities and NPK concentrations, is a promising research field. Therefore, with a two-step experiment, the study aimed to assay the physiological responses of a commonly used urban tree species (Tilia × europaea L.) to 1.5 % (w/w) biochar amendment (B), and secondly, to assess the ability of trees, grown in biochar amended soil, to tolerate a period of drought. Biochar amendment increased P and K availability in the soil, resulting in higher P and K concentrations in B than control leaves, according to the leaf stage. This induced B trees, higher values in both total biomass than controls (+22 %) in well-watered plants. Moreover, the higher water availability in soil amended with biochar helped B trees to tolerate water stress, with better leaf photosynthetic performances and a faster recovery than stressed controls after the re-watering. This study highlights the dual function of the biochar, improving CO sequestration and soil properties, and at the same time, enhancing plant physiological responses to environmental constraints. The use of biochar at the tree planting, especially in an urban environment, is a feasible and environmentally sustainable strategy to improve the success during the tree establishment phase.
树木在城市环境中起着至关重要的作用，可以缓解城市化带来的负面影响，因此，地方政府大力推行植树政策。然而，较差的土壤质量和忽视树木维护（例如灌溉和施肥）会在树木定植阶段严重影响植物健康状况。生物炭的使用可以为土壤提供持久的碳，并同时改善土壤性质（例如，提高保水能力）、土壤酶活性和 NPK 浓度，这是一个很有前景的研究领域。因此，本研究采用两步实验，旨在测定一种常用城市树种（椴树×欧洲椴）对 1.5%（w/w）生物炭（B）添加的生理响应，其次，评估生长在生物炭改良土壤中的树木耐受干旱期的能力。生物炭的添加增加了土壤中 P 和 K 的有效性，导致 B 组叶片中的 P 和 K 浓度高于对照组，根据叶片阶段。这促使 B 组树木的总生物量比对照组高出 22%，在水分充足的植物中。此外，土壤中生物炭的高水分可用性有助于 B 组树木耐受水分胁迫，在重新浇水后，B 组树木的叶片光合性能更好，恢复更快。本研究强调了生物炭的双重功能，它可以改善 CO2 固存和土壤性质，同时增强植物对环境胁迫的生理响应。在植树时使用生物炭，特别是在城市环境中，是一种可行的、环境可持续的策略，可以提高树木定植阶段的成功率。
