The degradation of soil often occurs due to the depletion of organic matter. Both biochar and straw have value as two primary means of remediating soil. In this study, we compared the effects of biochar and straw on soil organic carbon pools and on microbial communities in degraded soil. We added straw (maize) and biochar (maize-derived) to the degraded soil at the ratios of total soil weight (0, 1, 2, or 4%), respectively. Soil samples were collected after 180 days. We determined that upon straw addition, there was an increase in microbial biomass carbon (MBC), dissolved organic carbon (DOC), and easily oxidizable carbon (EOC). Upon biochar addition, there was an increase in soil total organic carbon and recalcitrant organic carbon. Analysis of bacterial community was conducted via 16SrDNA sequencing with an Illumina MiSeq platform and revealed that the relative abundance of Actinobacteria increased, but the Bacteroidetes and Chloroflexi decreased with straw addition. We further found that the addition of straw altered the Shannon and Simpson diversity index values, whereas biochar did not impact soil bacterial diversity. Nonmetric multidimensional scaling and canonical correspondence analyses revealed that bacterial community structure was influenced by both biochar and straw addition. Mantel testing further revealed that this community structure was associated with soil EOC ( r = 0.286, P = 0.001), DOC ( r = 0.174, P = 0.002), and MBC ( r = 0.299, P = 0.002) upon straw treatments. These results suggested that straw can improve soil labile organic carbon pools and soil bacterial communities better than biochar, whereas biochar (via pyrolysis at 550 °C, for 2 h) can improve carbon sequestration better than straw in degraded soil.

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比较生物炭和秸秆改良对退化土壤土壤碳库和细菌群落结构的影响

土壤的退化往往是由于有机质的枯竭而发生的。生物炭和秸秆都具有作为土壤修复的两种主要手段的价值。在这项研究中，我们比较了生物炭和秸秆对土壤有机碳库和退化土壤中微生物群落的影响。我们分别以总土壤重量的比例（0、1、2 或 4%）将秸秆（玉米）和生物炭（玉米衍生的）添加到退化的土壤中。180 天后收集土壤样品。我们确定添加秸秆后，微生物生物量碳 (MBC)、溶解有机碳 (DOC) 和易氧化碳 (EOC) 增加。添加生物炭后，土壤总有机碳和顽固有机碳增加。使用 Illumina MiSeq 平台通过 16SrDNA 测序对细菌群落进行分析，结果表明放线菌的相对丰度增加，但拟杆菌和绿屈曲菌随着秸秆的加入而减少。我们进一步发现，添加秸秆改变了香农和辛普森多样性指数值，而生物炭不影响土壤细菌多样性。非度量多维标度和规范对应分析表明细菌群落结构受生物炭和秸秆添加的影响。Mantel 测试进一步表明，这种群落结构与秸秆处理后的土壤 EOC ( r = 0.286, P = 0.001)、DOC ( r = 0.174, P = 0.002) 和 MBC ( r = 0.299, P = 0.002) 相关。