Nitrogen addition increases the contents of glomalin-related soil protein and soil organic carbon but retains aggregate stability in a Pinus tabulaeformis forest

PeerJ

article

Lipeng Sun¹  Hang Jing¹  Guoliang Wang¹  Guobin Liu¹ 

[1] Institute of Soil and Water Conservation, Northwest A&F University;State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources

关键词: Aggregate;    Mean weight diameter;    Glomalin-related soil protein;    Soil organic carbon;    Nitrogen deposition;   

DOI  :  10.7717/peerj.5039

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

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 by altering the distribution of GRSP and SOC in different aggregate fractions remains unknown. Methods We used a gradient N addition (0–9 g N m−2 y−1) in Pinus tabulaeformis250 μm, micro-aggregate: 250–53 μm, and fine material: <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 different 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−1 at 6 g N m−2 y−1. The micro-aggregates had the lowest EE-GRSP content (0.148 mg g−1) at 6 g N m−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 fine material 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 Glomalin-related soil protein 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.

【 授权许可】

CC BY