Federal University of Ceara, Fortaleza, Ceará, Brazil.
Federal University of Piauí, Teresina, Piauí, Brazil.
Sci Rep. 2024 Oct 30;14(1):26065. doi: 10.1038/s41598-024-77368-9.
Biochar is an effective material for enhancing soil ecosystem services. However, the specific impacts of biochar on microbial indicators, particularly in degraded soils, remain poorly understood. This study aimed to evaluate the effects of biochar produced from cashew residues and sewage sludge, in a highly degraded soil, on microbial indicators. We analyzed soil chemical composition and microbial biomass C and N, enzyme activity, and stoichiometry. Cashew biochar increased soil respiration, indicating a higher availability of C to microorganisms compared to sewage sludge biochar and a better adaptation of soil microbial communities to C-rich organic material obtained from a native plant. Although the biochar differentially impacted microbial biomass C, both significantly increased N in the microbial biomass. Arylsulphatase activity did not respond to biochar application, while β-glucosidase, urease, and phosphatases showed significant changes with biochar treatments. Importantly, stoichiometry and vector analysis revealed that both types of biochar increased P limitation for soil microbes. Conversely, both biochar alleviated C and N limitations for the soil microbes. Thus, biochar applications in highly degraded soils should be supplemented with external P sources to maintain soil functions, mainly for cashew residues. Our results provide evidence that biochar can restore soil biological properties and enhance the availability of C and N to microorganisms. These findings have significant implications for restoration practices in degraded lands of semiarid regions.
生物炭是增强土壤生态系统服务的有效物质。然而，生物炭对微生物指标的具体影响，特别是在退化土壤中，仍了解甚少。本研究旨在评估从腰果残渣和污水污泥中生产的生物炭在高度退化土壤中对微生物指标的影响。我们分析了土壤化学组成以及微生物生物量 C 和 N、酶活性和化学计量。与污水污泥生物炭相比，腰果生物炭增加了土壤呼吸，表明微生物可利用的 C 更高，土壤微生物群落对来自本地植物的富碳有机物质的适应性更好。尽管生物炭对微生物生物量 C 的影响存在差异，但两者都显著增加了微生物生物量中的 N。芳基硫酸酯酶活性对生物炭的应用没有响应，而β-葡萄糖苷酶、脲酶和磷酸酶的活性随着生物炭处理而发生显著变化。重要的是，化学计量和向量分析表明，这两种生物炭都增加了土壤微生物对 P 的限制。相反，两种生物炭都缓解了土壤微生物对 C 和 N 的限制。因此，在高度退化的土壤中应用生物炭时，应补充外部 P 源以维持土壤功能，特别是对于腰果残渣。我们的研究结果表明，生物炭可以恢复土壤的生物特性，并增加 C 和 N 对微生物的可利用性。这些发现对干旱半干旱地区退化土地的恢复实践具有重要意义。
