Journal article

Publication year: 2020

Journal: Soil Biology and Biochemistry

Volume number: 149

ISSN: 0038-0717

DOI Link: https://doi.org/10.1016/j.soilbio.2020.107962

Publisher: Elsevier

Abstract: 
Nitrogen (N) deposition can profoundly alter soil N cycling of grassland ecosystems. Substrates and soil acidification are expected to modify soil N transformations in response to elevated N deposition. Here, we carried out N-15 tracing studies to test the effects of N addition rates (low: 30 kg N ha(-1) and high: 90/120 kg N ha(-1)) and soil acidification on gross N transformation rates using two typical Chinese grassland soils, an alpine calcareous soil and a temperate neutral soil. We found that N addition significantly increased the ratio of gross nitrification rate to gross ammonia immobilization rate (N/I) in both soils, but gross N transformation rates changed differently as a function of N addition rates and soil types. In the calcareous soil, N addition increased soil gross N transformations, largely due to mineral N substrates, SOC, TN and fungal dominance. In contrast, low N addition did not affect gross N transformation rates in the neutral soil, but high N addition significantly decreased gross N transformation rates. Although both SOC and TN were increased with N addition in the neutral soil, N-induced soil pH decline decreased gross N transformation rates. Our results indicate that the effects of N addition on grassland soil gross N transformations are highly dependent on mineral N substrates, SOC and TN. Soil acidification played a more important role than SOC and TN in gross N transformation rate changes in response to elevated N deposition. These findings suggest that the different changes of gross N transformation rates in response to N deposition and soil properties (e.g. SOC, TN and soil pH) should be integrated into biogeochemical models to better predict grassland ecosystem N cycling in the future scenarios of N deposition.

Harvard Citation style: Hao, T., Zhang, Y., Zhang, J., Müller, C., Li, K., Zhang, K., et al. (2020) Chronic nitrogen addition differentially affects gross nitrogen transformations in alpine and temperate grassland soils, Soil Biology and Biochemistry, 149, Article 107962. https://doi.org/10.1016/j.soilbio.2020.107962

APA Citation style: Hao, T., Zhang, Y., Zhang, J., Müller, C., Li, K., Zhang, K., Chu, H., Stevens, C., & Liu, X. (2020). Chronic nitrogen addition differentially affects gross nitrogen transformations in alpine and temperate grassland soils. Soil Biology and Biochemistry. 149, Article 107962. https://doi.org/10.1016/j.soilbio.2020.107962