Institute of Loess Plateau, Shanxi University, Taiyuan, Shanxi 030006, China; Institute of Resources and Environmental Engineering, Shanxi University, Taiyuan, Shanxi 030006, China.
Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, Zhejiang 310058, China.
Sci Total Environ. 2018 Dec 15;645:887-894. doi: 10.1016/j.scitotenv.2018.07.224. Epub 2018 Jul 24.
Dry land is a massive contributor to global nitrous oxide (NO) production and biochar is a potential material for soil amendment that can impact soil NO emission. Considering that the moisture content of dry land is usually changeable, it is essential to investigate the effect of biochar on soil NO emission under different moisture contents. Therefore, column experiments were conducted with two biochars (B300 and B500, biochars pyrolyzed at 300 and 500 °C, respectively) under five moisture contents (18%, 21%, 24%, 27% and 30%, w/w). The results showed that B300 promoted NO emission under the moisture contents of 18%, 21% and 24% by increasing the content of dissolved organic carbon and thus enhancing the microbial processes related to NO production. However, when the moisture contents were 27% and 30%, the promotion of NO production was overwhelmed by the improvement in NO reduction due to the B300 induced increase in the abundance ratio of nosZ to nirS, leading to the decrease in NO emission. Moreover, B500 did not alter the content of dissolved organic matter significantly and thus caused no significant change in NO emission when the moisture contents were 18%, 21% and 24%. But it was able to increase the abundance ratio of nosZ to nirS and thus decrease NO emission when the moisture contents were 27% and 30%. The results further clarified the effect of biochar on soil NO emission and helped to evaluate the NO-suppressing-potential of biochar.
旱地是全球一氧化二氮（NO）产生的重要贡献者，生物炭是一种潜在的土壤改良剂，可以影响土壤 NO 排放。考虑到旱地的含水量通常是变化的，因此研究生物炭在不同含水量下对土壤 NO 排放的影响至关重要。因此，进行了柱实验，使用两种生物炭（B300 和 B500，分别在 300 和 500°C 下热解的生物炭）在五种含水量（18%、21%、24%、27%和 30%，w/w）下进行。结果表明，B300 通过增加溶解有机碳的含量，促进了 18%、21%和 24%含水量下的 NO 排放，从而增强了与 NO 产生相关的微生物过程。然而，当含水量为 27%和 30%时，由于 B300 诱导的 nosZ 对 nirS 的丰度比增加，NO 还原的改善超过了 NO 产生的促进作用，导致 NO 排放减少。此外，B500 对溶解有机物质的含量没有显著影响，因此在含水量为 18%、21%和 24%时，NO 排放没有显著变化。但在含水量为 27%和 30%时，它能够增加 nosZ 对 nirS 的丰度比，从而减少 NO 排放。结果进一步阐明了生物炭对土壤 NO 排放的影响，并有助于评估生物炭的抑制 NO 排放潜力。
