Nitrogen addition increases the contents of glomalin-related soil protein and soil organic carbon but retains aggregate stability in a Pinus tabulaeformis forest
- Published
- Accepted
- Subject Areas
- Soil Science, Forestry
- Keywords
- Aggregate, Mean weight diameter, Glomalin-related soil protein, Soil organic carbon, Nitrogen deposition
- Copyright
- © 2018 Sun et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2018. Nitrogen addition increases the contents of glomalin-related soil protein and soil organic carbon but retains aggregate stability in a Pinus tabulaeformis forest. PeerJ Preprints 6:e26649v1 https://doi.org/10.7287/peerj.preprints.26649v1
Abstract
Background: Glomalin-related soil protein (GRSP) and soil organic carbon (SOC) contribute to the formation and stability of soil aggregates, but the mechanism by which global atmospheric nitrogen (N) deposition changes soil aggregate stability when it alters the distribution of GRSP and SOC in different aggregate fractions remains unknown. Methods: We used a gradient N addition (0–9 g N–2 y–1) in Pinus tabulaeformis forest for 2 years in northeast China and then examined the changes in SOC contents, total GRSP (T-GRSP), and easily extractable GRSP (EE-GRSP) contents in three soil aggregate fractions (macro-aggregate: >250 μm, micro-aggregate: 250–53 μm, and clay–silt aggregate: <53 μm) and their relationship with aggregate stability. Results: (1) The soil was dominated by macro-aggregates. Short term N addition had no significant effect on mean weight diameter (MWD) and geometric mean diameter (GMD). (2) GRSP varied among aggregate fractions, and N addition had variable effects on the distribution of GRSP in aggregate fractions. The EE-GRSP content in the macro-aggregates increased initially and then decreased with increasing N addition levels, having a peak value of 0.480 mg/g at 6 g N–2 y–1. The micro-aggregates had the lowest EE-GRSP content (0.148 mg/g) at 6 g N–2 y–1. Furthermore, the T-GRSP content significantly increased in the aggregate fractions with the N addition levels. (3) The macro-aggregate had the highest SOC content, followed by the micro-aggregate and the clay–silt aggregate had the lowest SOC content. N addition significantly increased the SOC content in all the aggregate fractions. (4) GRSP and SOC contents were not significantly correlated with MWD. Conclusion: The distributions of GRSP and SOC varied with aggregate fractions. GRSP and SOC contents increased by N addition, but this increase did not enhance aggregate stability in short term, and the improvement of stability might depend on binding agents and incubation time.
Author Comment
This is a submission to PeerJ for review.