Citation
Ochoa Hueso, Raúl and Maestre, Fernando T. and Rios, Asuncion de los and Valea, Sergio and Theobald, Mark Richard and Vivanco, Marta G. and Manrique, Esteban and Bowker, Mathew A.
(2013).
Nitrogen deposition alters nitrogen cycling and reduces soil carbon content in low-productivity semiarid Mediterranean ecosystems..
"Environmental Pollution"
(n. 179);
pp. 185-193.
ISSN 0269-7491.
https://doi.org/10.1016/j.envpol.2013.03.060.
Abstract
Anthropogenic N deposition poses a threat to European Mediterranean ecosystems. We combined data from an extant N deposition gradient (4.3–7.3 kg N ha−1 yr−1) from semiarid areas of Spain and a field experiment in central Spain to evaluate N deposition effects on soil fertility, function and cyanobacteria community. Soil organic N did not increase along the extant gradient. Nitrogen fixation decreased along existing and experimental N deposition gradients, a result possibly related to compositional shifts in soil cyanobacteria community. Net ammonification and nitrification (which dominated N-mineralization) were reduced and increased, respectively, by N fertilization, suggesting alterations in the N cycle. Soil organic C content, C:N ratios and the activity of β-glucosidase decreased along the extant gradient in most locations. Our results suggest that semiarid soils in low-productivity sites are unable to store additional N inputs, and that are also unable to mitigate increasing C emissions when experiencing increased N deposition.