Long‐term inorganic nitrogen application changes the ammonia‐oxidizing archaeal community composition in paddy soils

Abstract

The abundance and taxonomic composition of ammonia‐oxidizing archaea (AOA) were assessed in paddy soils that had received more than 50 years of fertilization with and without inorganic N. The inorganic N fertilized treatments were: NPK and NPK + CO (nitrogen (N), phosphorus (P), potassium (K) and compost (CO)). The treatments without inorganic N were: CO, PK and control (unfertilized soils). Quantitative PCR (qPCR) analysis of the archaeal amoA gene showed no significant changes in AOA abundance following the long‐term application of inorganic N fertilizers. However, subsequent analysis of amoA gene sequencing data showed that inorganic N application significantly changed the AOA community composition and alpha diversity indices. Edge principal components analysis (PCA) showed varying contributions of distinct AOA lineages in separating samples according to the fertilization treatment. Addition of inorganic N favoured an increase in the abundance of AOA lineages belonging to Nitrososphaera, and the treatments without inorganic N additions formed a separate cluster dominated by Nitrosotalea lineage. The distinct response of the two AOA lineages points towards different community organization of soil AOA and strongly supports the concept of habitat partitioning in paddy soil ecosystems. Highlights Lineages of AOA responded differently to different N management practices. Long‐term N fertilization selectively enriched AOA lineages, with C:N ratio a factor associated with such changes Inorganic N favoured Nitrososphaera lineage abundance Regardless of fertilizer status, Nitrosotalea lineage was dominant in the absence of inorganic N fertilization.

Nitrification and Denitrification Gene Abundances under Stable Soil Chemical Properties Established by Long-Term Compost Fertilization

“…Groups of microbial guilds associated with nitrogen cycling have also responded differently to long-term fertilization, as evidenced by the distinct microbial guilds, in terms of diversity and abundance, particularly associated to the different fertilization treatments. These are observed in long-term amendments with compost and NPK + compost [20,42,45], and inorganic or chemical fertilizer including urea [6,20,42,45]. Differences in the fertilization application in terms of the amount of fertilization over long-term fertilization also show group-specific changes in microbial communities associated to nitrogen cycling [2,46], creating paddy fields with distinct microbial guilds that are directly affected by fertilization treatments and soil properties.…”

“…To predict soil productivity and understand critical processes and linkages in soil, predicting longterm changes in the microbial composition and structure over extended periods is critical [5]. For instance, the ammonia-oxidizing clades at the genus level responded differently to longterm inorganic nitrogen amendment in paddy fields [6]. Long-term nitrogen application also led to taxon-specific responses in the different microbial guilds associated with nitrogen cycling microbial communities [2].…”