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Nitrogen and phosphorus co‐limit mineralization of labile carbon in deep subsoil
Author(s) -
Peixoto Leanne,
Elsgaard Lars,
Rasmussen Jim,
Olesen Jørgen E.
Publication year - 2021
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/ejss.13083
Subject(s) - subsoil , mineralization (soil science) , nitrogen , chemistry , nutrient , environmental chemistry , phosphorus , nitrogen cycle , agronomy , environmental science , soil science , soil water , biology , organic chemistry
The growth of deep‐rooted crops has the potential to increase carbon deposition within deep subsoil layers, thereby contributing to climate change mitigation. Yet, the mechanisms of labile carbon stabilization in deep subsoils remain uncertain. Here we studied the effect of nitrogen, phosphorus and sulphur limitations on the microbial mineralization of added glucose and an artificial root exudate mixture (both spiked with 14 C‐glucose) in intact soil samples from a deep subsoil (5–6 m) over a 10‐week incubation period, where the temporal respiration of CO 2 and 14 CO 2 were quantified. We found that mineralization was co‐limited by nitrogen and phosphorus, but the cumulative amount of CO 2 emitted was significantly larger from artificial root exudates than glucose, suggesting that the nitrogen carried in amino acids in root exudates (here, L‐arginine) was sufficient to overcome the nitrogen limitation in this subsoil. Highlights Labile C substrates and nutrients from deep‐rooted crops may affect the potential for C sequestration in subsoil. Deep subsoil was incubated with glucose and artificial root exudates amended with N, P, and S. C mineralization was co‐limited by N and P, but less so in soil amended with glucose. Amino acid derived‐N in exudates from deep‐rooted crops may alleviate the N limitation in deep subsoils.