Straw-related carbon (C) dynamics are central for C accrual
in
agro-ecosystems and should be assessed by investigating their decomposition
and soil organic carbon (SOC) priming effects. Our understanding of
biotic and abiotic mechanisms underpinning these two C processes,
however, is still not sufficiently profound. Soils that had received
organic and mineral fertilizers for 26 years were sampled for a 28
day incubation experiment to assess 13C-labeled straw decomposition
and SOC priming effects. On the basis of analyzing physicochemical
properties, fungal taxonomic (MiSeq sequencing) and functional (metagenomics)
guilds, we quantified the contributions of biotic and abiotic attributes
to straw decomposition and SOC priming. Here, we propose two distinct
mechanisms underlying straw decomposition and SOC priming in agriculture
soils: (i) accelerated straw mineralization in manure-treated soils
was mainly driven by biotic forces, while (ii) larger SOC priming
in NPK-amended soils was through abiotic regulation.