%P 185-193
%I Agronomos
%L upm25901
%J Environmental Pollution
%N 179
%R 10.1016/j.envpol.2013.03.060
%X 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.
%A Raúl Ochoa Hueso
%A Fernando T. Maestre
%A Asuncion de los Rios
%A Sergio Valea
%A Mark Richard Theobald
%A Marta G. Vivanco
%A Esteban Manrique
%A Mathew A. Bowker
%D 2013
%T Nitrogen deposition alters nitrogen cycling and reduces soil carbon content in low-productivity semiarid Mediterranean ecosystems.