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Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Canopy and understory nitrogen additions differently affect soil microbial residual carbon in a temperate forest
AU - Chen, Y.
AU - Zhang, Y.
AU - Zhang, X.
AU - Stevens, C.
AU - Fu, S.
AU - Feng, T.
AU - Li, X.
AU - Chen, Q.
AU - Liu, S.
AU - Hu, S.
PY - 2024/7/31
Y1 - 2024/7/31
N2 - Atmospheric nitrogen (N) deposition in forests can affect soil microbial growth and turnover directly through increasing N availability and indirectly through altering plant‐derived carbon (C) availability for microbes. This impacts microbial residues (i.e., amino sugars), a major component of soil organic carbon (SOC). Previous studies in forests have so far focused on the impact of understory N addition on microbes and microbial residues, but the effect of N deposition through plant canopy, the major pathway of N deposition in nature, has not been explicitly explored. In this study, we investigated whether and how the quantities (25 and 50 kg N ha−1 year−1) and modes (canopy and understory) of N addition affect soil microbial residues in a temperate broadleaf forest under 10‐year N additions. Our results showed that N addition enhanced the concentrations of soil amino sugars and microbial residual C (MRC) but not their relative contributions to SOC, and this effect on amino sugars and MRC was closely related to the quantities and modes of N addition. In the topsoil, high‐N addition significantly increased the concentrations of amino sugars and MRC, regardless of the N addition mode. In the subsoil, only canopy N addition positively affected amino sugars and MRC, implying that the indirect pathway via plants plays a more important role. Neither canopy nor understory N addition significantly affected soil microbial biomass (as represented by phospholipid fatty acids), community composition and activity, suggesting that enhanced microbial residues under N deposition likely stem from increased microbial turnover. These findings indicate that understory N addition may underestimate the impact of N deposition on microbial residues and SOC, highlighting that the processes of canopy N uptake and plant‐derived C availability to microbes should be taken into consideration when predicting the impact of N deposition on the C sequestration in temperate forests.
AB - Atmospheric nitrogen (N) deposition in forests can affect soil microbial growth and turnover directly through increasing N availability and indirectly through altering plant‐derived carbon (C) availability for microbes. This impacts microbial residues (i.e., amino sugars), a major component of soil organic carbon (SOC). Previous studies in forests have so far focused on the impact of understory N addition on microbes and microbial residues, but the effect of N deposition through plant canopy, the major pathway of N deposition in nature, has not been explicitly explored. In this study, we investigated whether and how the quantities (25 and 50 kg N ha−1 year−1) and modes (canopy and understory) of N addition affect soil microbial residues in a temperate broadleaf forest under 10‐year N additions. Our results showed that N addition enhanced the concentrations of soil amino sugars and microbial residual C (MRC) but not their relative contributions to SOC, and this effect on amino sugars and MRC was closely related to the quantities and modes of N addition. In the topsoil, high‐N addition significantly increased the concentrations of amino sugars and MRC, regardless of the N addition mode. In the subsoil, only canopy N addition positively affected amino sugars and MRC, implying that the indirect pathway via plants plays a more important role. Neither canopy nor understory N addition significantly affected soil microbial biomass (as represented by phospholipid fatty acids), community composition and activity, suggesting that enhanced microbial residues under N deposition likely stem from increased microbial turnover. These findings indicate that understory N addition may underestimate the impact of N deposition on microbial residues and SOC, highlighting that the processes of canopy N uptake and plant‐derived C availability to microbes should be taken into consideration when predicting the impact of N deposition on the C sequestration in temperate forests.
U2 - 10.1111/gcb.17427
DO - 10.1111/gcb.17427
M3 - Journal article
VL - 30
JO - Global Change Biology
JF - Global Change Biology
SN - 1354-1013
IS - 7
M1 - e17427
ER -