Journal article

Publication year: 2023

Journal: Soil Biology and Biochemistry

Volume number: 186

ISSN: 0038-0717

eISSN: 1879-3428

DOI Link: https://doi.org/10.1016/j.soilbio.2023.109176

Publisher: Elsevier

Abstract: 
Inorganic nitrogen (N) is the most important nutrient in soils, because it limits plant productivity and affects ecosystem function. It is produced by the mineralization of organic N to ammonium (NH4+) (M-Norg) and the subsequent nitrification of NH4+ to nitrate (NO3-) (O-NH4). Previous studies systematically evaluated the patterns and mechanisms of M-Norg and O-NH4 in soils on a global scale, but the characteristics of both processes in karst regions remain largely unknown. We conducted a(15)N-tracing study to investigate the rates of M-Norg and O-NH4, and the factors that influence these processes, from different natural ecosystems (mainly grass, shrub and forest) within karst regions. The rates of both M-Norg and O-NH4 exhibited large spatial variations, ranging from 0.42 to 23.8 mg N kg(-1) d(-1) and from 0.23 to 29.1 mg N kg(-1) d(-1), respectively, which were mainly ascribed to the heterogeneity of soil nutrients in karst regions. The concentrations of SOC, TN, soil inorganic N, NO3-, total K, Ca, Mg, WHC, and the rates of M-Norg and O-NH4 ranked as grass < shrub < forest, indicating that the improvement of soil conditions could stimulate the inorganic N production along the vegetation succession. The relative importance of the explanatory variables for inorganic N production suggested that the soil calcium concentration was the predominant determinant of the rates of M-Norg and O-NH4 in karst regions. A structural equation model indicated that soil calcium stimulates organic N accumulation, by serving as the substrate driving the increased rates of M-Norg and O-NH4 under high pH conditions. Overall, our results highlight the importance of soil calcium in determining the rates of M-Norg and O-NH4 in karst regions.

Harvard Citation style: Yang, S., Yang, L., Wen, D., Liu, L., Ni, K., Cao, J., et al. (2023) Soil calcium constrains nitrogen mineralization and nitrification rates in subtropical karst regions, Soil Biology and Biochemistry, 186, Article 109176. https://doi.org/10.1016/j.soilbio.2023.109176

APA Citation style: Yang, S., Yang, L., Wen, D., Liu, L., Ni, K., Cao, J., Zhu, T., & Müller, C. (2023). Soil calcium constrains nitrogen mineralization and nitrification rates in subtropical karst regions. Soil Biology and Biochemistry. 186, Article 109176. https://doi.org/10.1016/j.soilbio.2023.109176