School of Chemical & Environmental Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China; Department of Renewable Resources, University of Alberta, Edmonton, Alberta T6G 2E3, Canada.
Department of Renewable Resources, University of Alberta, Edmonton, Alberta T6G 2E3, Canada.
Ecotoxicol Environ Saf. 2023 Nov 1;266:115579. doi: 10.1016/j.ecoenv.2023.115579. Epub 2023 Oct 17.
In the background of climate warming, the demand for improving soil quality and carbon (C) sequestration is increasing. The application of biochar to soil has been considered as a method for mitigating climate change and enhancing soil fertility. However, it is uncertain whether the effects of biochar application on C-mineralization and N transformation are influenced by the presence or absence of plant growth-promoting bacteria (PGPB) and soil nitrogen (N) level. An incubation study was conducted to investigate whether the effects of biochar application (0 %, 1 %, 2 % and 4 % of soil mass) on soil respiration, N status, and microbial attributes were altered by the presence or absence of PGPB (i.e., Sphingobium yanoikuyae BJ1) under two soil N levels (N0 and N1 soils as created by the addition of 0 and 0.2 g kg urea- N, respectively). The results showed that biochar, BJ1 strain and their interactive effects on cumulative CO emissions were not significant in N0 soils, while the effects of biochar on the cumulative CO emissions were dependent on the presence or absence of BJ1 in N1 soils. In N1 soils, applying biochar at 2 % and 4 % increased the cumulative CO emissions by 141.0 % and 166.9 %, respectively, when BJ1 was absent. However, applying biochar did not affect CO emissions when BJ1 was present. In addition, the presence of BJ1 generally increased ammonium contents in N0 soils, but decreased nitrate contents in N1 soils relative to the absence of BJ1, which indicates that the combination of biochar and BJ1 is beneficial to play the N fixation function of BJ1 in N0 soils. Our results highlight that biochar addition influences not only soil C mineralization but also soil available N, and the direction and magnitude of these effects are highly dependent on the presence of PGPB and the soil N level.
在气候变暖的背景下，提高土壤质量和固碳（C）的需求不断增加。将生物炭应用于土壤被认为是一种缓解气候变化和增强土壤肥力的方法。然而，生物炭的应用是否会影响土壤中 C 的矿化和 N 的转化，这取决于是否存在植物促生菌（PGPB）和土壤氮（N）水平，目前还不确定。本研究通过培养实验，研究了在两种土壤氮水平（添加 0 和 0.2 g kg-1 尿素-N 分别创建 N0 和 N1 土壤）下，生物炭（土壤质量的 0%、1%、2%和 4%）的添加是否会通过存在或不存在植物促生菌（即，鞘氨醇单胞菌 BJ1）来改变土壤呼吸、N 状况和微生物特性。结果表明，在 N0 土壤中，生物炭、BJ1 菌株及其对累积 CO 排放的互作效应并不显著，而生物炭对累积 CO 排放的影响取决于 N1 土壤中 BJ1 的存在与否。在 N1 土壤中，当 BJ1 不存在时，添加 2%和 4%的生物炭分别使累积 CO 排放量增加了 141.0%和 166.9%。然而，当 BJ1 存在时，生物炭的添加并不影响 CO 的排放。此外，与不存在 BJ1 相比，BJ1 的存在通常会增加 N0 土壤中的铵态氮含量，但会降低 N1 土壤中的硝态氮含量，这表明生物炭和 BJ1 的组合有利于发挥 BJ1 在 N0 土壤中的固氮功能。我们的研究结果表明，生物炭的添加不仅影响土壤 C 的矿化，而且影响土壤有效氮，这些影响的方向和程度高度依赖于 PGPB 的存在和土壤氮水平。
