Sun Ping, Zhao Ziting, Fan Pingshan, Chen Wei, Ruan Yunze, Wang Qing
Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical Crops, Hainan University, Haikou, China.
Front Microbiol. 2021 Oct 5;12:715070. doi: 10.3389/fmicb.2021.715070. eCollection 2021.
Autotrophic nitrification is regulated by canonical ammonia-oxidizing archaea (AOA) and bacteria (AOB) and nitrite-oxidizing bacteria (NOB). To date, most studies have focused on the role of canonical ammonia oxidizers in nitrification while neglecting the NOB. In order to understand the impacts of combined biochar and chemical fertilizer addition on nitrification and associated nitrifiers in plant rhizosphere soil, we collected rhizosphere soil from a maize field under four different treatments: no fertilization (CK), biochar (B), chemical nitrogen (N) + phosphorus (P) + potassium (K) fertilizers (NPK), and biochar + NPK fertilizers (B + NPK). The potential nitrification rate (PNR), community abundances, and structures of AOA, AOB, complete ammonia-oxidizing bacteria (Comammox clade A), and - and -like NOB were measured. Biochar and/or NPK additions increased soil pH and nutrient contents in rhizosphere soil. B, NPK, and B + NPK treatments significantly stimulated PNR and abundances of AOB, Comammox, and - and -like NOB, with the highest values observed in the B + NPK treatment. Pearson correlation and random forest analyses predicted more importance of AOB, Comammox clade A, and - and -like NOB abundances over AOA on PNR. Biochar and/or NPK additions strongly altered whole nitrifying community structures. Redundancy analysis (RDA) showed that nitrifying community structures were significantly affected by pH and nutrient contents. This research shows that combined application of biochar and NPK fertilizer has a positive effect on improving soil nitrification by affecting communities of AOB and NOB in rhizosphere soil. These new revelations, especially as they related to understudied NOB, can be used to increase efficiency of agricultural land and resource management.
自养硝化作用受典型的氨氧化古菌（AOA）、细菌（AOB）和亚硝酸盐氧化细菌（NOB）调控。迄今为止，大多数研究都集中在典型氨氧化菌在硝化作用中的作用，而忽视了NOB。为了了解生物炭和化肥配施对植物根际土壤硝化作用及相关硝化细菌的影响，我们采集了处于四种不同处理下的玉米田根际土壤：不施肥（CK）、生物炭（B）、化学氮（N）+磷（P）+钾（K）肥（NPK）以及生物炭+NPK肥（B+NPK）。测定了潜在硝化速率（PNR）、AOA、AOB、完全氨氧化细菌（Comammox进化枝A）以及-和-样NOB的群落丰度和结构。添加生物炭和/或NPK提高了根际土壤的pH值和养分含量。B、NPK和B+NPK处理显著刺激了PNR以及AOB、Comammox和-和-样NOB的丰度，其中B+NPK处理的值最高。Pearson相关性分析和随机森林分析预测，AOB、Comammox进化枝A以及-和-样NOB的丰度对PNR的影响比AOA更为重要。添加生物炭和/或NPK强烈改变了整个硝化群落结构。冗余分析（RDA）表明，硝化群落结构受pH值和养分含量的显著影响。本研究表明，生物炭与NPK肥配施通过影响根际土壤中AOB和NOB群落对提高土壤硝化作用具有积极影响。这些新发现，尤其是与研究较少的NOB相关的发现，可用于提高农业土地和资源管理效率。
