State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Sci Total Environ. 2020 Sep 10;734:139398. doi: 10.1016/j.scitotenv.2020.139398. Epub 2020 May 12.
Carbonaceous materials are soil conditioners that affect nitrogen cycles. However, how carbonaceous materials influence nitrite-oxidizing bacteria (NOB) is yet unclear. In this study, we investigated the NOB community and its potential activities under different treatments (control, biochar, straw, limestone, biochar + limestone, and straw + limestone) in an Alfisol, a type of arable soil depleted in calcium carbonate but enriched in aluminum- and iron-bearing minerals. Treatments with limestone increased soil pH, and straw inputs caused an increment of available potassium (AK). Ammonia (NH) was inversely changed under the straw and biochar + limestone amendments. None of the treatments significantly impacted the abundance of Nitrobacter (nxrA) or the potential nitrite oxidation activity (PNO). The abundance of Nitrospira (nxrB) increased in the biochar + limestone-treated samples and was significantly correlated with PNO, pH, and AK. High-throughput sequencing results showed that the α-diversity of NOB did not change in response to the treatments. The dominant Nitrobacter OTUs were affiliated within the Clusters 3, 4, 8, and 9 (a new cluster named in this study), while those of Nitrospira were in the lineage II and Namibian soil cluster 2. The limited compositional variation for Nitrobacter was explained by pH, and that for Nitrospira by pH, TN, and NH. Among all available data in this study, the richness of Nitrospira was the most important predictor (73%) for PNO. Therefore, we assumed that the community of nitrite oxidizers (Nitrospira) could be relatively redundant in function, supported by the observation that the carbonaceous inputs did not impact either the potential activity or the α-diversity but did affect the abundance and community composition.
碳素材料是影响氮循环的土壤改良剂。然而，碳素材料如何影响亚硝酸盐氧化菌（NOB）尚不清楚。本研究在一种缺碳酸钙但富含铝和铁矿物的耕层土壤（ Alfisol）中，研究了不同处理（对照、生物炭、秸秆、石灰石、生物炭+石灰石和秸秆+石灰石）下的 NOB 群落及其潜在活性。石灰石处理增加了土壤 pH 值，秸秆输入导致有效钾（AK）增加。秸秆和生物炭+石灰石处理下氨（NH）含量降低。氮菌（nxrA）的丰度或潜在亚硝酸盐氧化活性（PNO）均不受任何处理的显著影响。生物炭+石灰石处理样品中 Nitrospira（nxrB）的丰度增加，与 PNO、pH 值和 AK 呈显著正相关。高通量测序结果表明，NOB 的 α 多样性对处理没有变化。Nitrobacter 的优势 OTU 属于第 3、4、8 和 9 簇（本研究中命名的一个新簇），而 Nitrospira 的 OTU 属于第 II 谱系和纳米比亚土壤簇 2。Nitrobacter 的有限组成变化由 pH 解释，Nitrospira 由 pH、TN 和 NH 解释。在本研究的所有可用数据中，Nitrospira 的丰富度是 PNO 的最重要预测因子（73%）。因此，我们假设亚硝酸盐氧化菌（Nitrospira）的群落功能可能相对冗余，这一假设得到了以下观察结果的支持：碳素输入既不影响潜在活性，也不影响 α 多样性，但确实影响了丰度和群落组成。
