Ammonia- and Nitrite-Oxidizing Bacteria are Dominant in Nitrification of Maize Rhizosphere Soil Following Combined Application of Biochar and Chemical Fertilizer

Abstract

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 Nitrospira clade A), and Nitrobacter- and Nitrospira-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 Nitrobacter- and Nitrospira-like NOB, with the highest values observed in the B + NPK treatment. Pearson correlation and random forest analyses predicted more importance of AOB, Comammox Nitrospira clade A, and Nitrobacter- and Nitrospira-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.

16S Amplicon Sequencing of Nitrifying Bacteria and Archaea Inhabiting Maize Rhizosphere and the Influencing Environmental Factors

“…Nitrospira is known to be well distributed globally and was found to be most abundant. It was recently observed by Sun, et al [46] in a maize rhizosphere. Moreover, Nitrobacter was noted in a maize-soybean rotation system by Meier, et al [47].…”

16S Metagenomics of Nitrifying Bacteria and Archaea Inhabiting Maize Rhizosphere and the Influencing Environmental Factors

“…Nitrospira is known to be well distributed globally and was found to be most abundant. It was recently observed by Sun, Zhao, Fan, Chen, Ruan and Wang [43] in a maize rhizosphere. Also, Nitrobacter was noted in a maize-soybean rotation system by Meier, Lopez-Guerrero, Guo, Schmer, Herr, Schnable, Alfano and Yang [44].…”

Biochar-based fertiliser improved the yield, quality and fertiliser utilisation of open field tomato in karst mountainous area

“…In addition, biochar can increase soil nutrient content, cation exchange capacity (CEC), and water retention capacity, and affects the diversity and structure of soil microbial communities directly (Kumar et al 2022). Meanwhile, biochar can also participate in the soil nutrient cycle of farmland ecosystems (Zhang et al 2021a) and has an important effect on the conversion, migration, and distribution of soil nutrients through their physicochemical properties or interaction with the soil (Sun et al 2021). Furthermore, biochar's rich chemical-reaction-type functional groups also endow the biochar with extremely strong adsorption capacity, which makes biochar a good fertiliser synergist and makes it possible to compound with mineral fertilisers to improve its utilisation (Yan et al 2021a).…”