Suchergebnisse

11 páginas, 3 tablas, 5 figuras. ; The aim of this study was to gain insights on the potential hydrological and biogeochemical mechanisms controlling the response of two nested Mediterranean catchments to long-term changes in atmospheric inorganic nitrogen and sulphate deposition. One catchment was steep and fully forested (TM9, 5.9 ha) and the other one had gentler slopes and heathlands in the upper part while side slopes were steep and forested (TM0, 205 ha). Both catchments were highly responsive to the 45% decline in sulphate concentration measured in atmospheric deposition during the 1980s and 1990s, with stream concentrations decreasing by 1.4 to 3.4 μeq L−1 y−1. Long-term changes in inorganic nitrogen in both, atmospheric deposition and stream water were small compared to sulphate. The quick response to changes in atmospheric inputs could be explained by the small residence time of water (4–5 months) in these catchments (inferred from chloride time series variance analysis), which was attributed to steep slopes and the role of macropore flow bypassing the soil matrix during wet periods. The estimated residence time for sulphate (1.5–3 months) was substantially lower than for chloride suggesting unaccounted sources of sulphate (i.e., dry deposition, or depletion of soil adsorbed sulphate). In both catchments, inorganic nitrogen concentration in stream water was strongly damped compared to precipitation and its residence time was of the order of decades, indicating that this essential nutrient was strongly retained in these catchments. Inorganic nitrogen concentration tended to be higher at TM0 than at TM9 which was attributed to the presence of nitrogen fixing species in the heathlands. Our results indicate that these Mediterranean catchments react rapidly to environmental changes, which make them especially vulnerable to changes in atmospheric deposition. ; S.B. work was funded by the Spanish Research Council (JAE-DOC027) and the Spanish CICT (Juan de la Cierva contract JCI-2008-177). The financial support from the Spanish Government projects CGL2009-13188-C03-01, MED_FORESTREAM (CGL2011-30590) and MONTES-Consolider (CSD-2008-00040) is fully acknowledged. ; Peer reviewed

10 pages, 1 figure, 1 table, 60 references.-- Trabajo publicado en la Section 2: Country Reports.-- El volumen consta de 202 páginas.-- Meeting at Soil Survey and Land Research Centre Cranfield University, Silsoe, UK., que tuvo lugar del 21-22, abril, 1998. ; Meetings of European Union Heads of Soil Survey Organisations were held in 1989 and 1994 respectively. Both were followed by publication of monographs describing the state-of-the-art in each of the member countries (Hodgson 1991; Le Bas & Jamagne 1996). Limited progress has been made in Spain since then, except for a proposal for an ambitious macroproject (PNCTA), the prospects for which now seem somewhat uncertain. Readers interested in historical aspects of Spanish pedology and/or soil mapping can refer to studies by Díaz Fierros (1979 and 1997) Mudarra (1989 and 1994); Sunyer (1996), Ibáñez el al. (1991, 1997), Boixadera and Ibáñez, (1996) and Guerra, (1997). This paper describes progress in soil survey from 1994 to 1998 and provides additional information on monitoring and soil databases developed in Spain. Nevertheless, some Spanish soil databases arising from some initiatives in Pan-European programmes are not included in the discussion here due to their particular scope. The Spanish contribution to the ICP Forest programme, recently published on a CD-ROM that holds morphological, taxonomic and analytical information corresponding to 453 soil profiles, is a case in point (Montoya & López-Arias, 1998). ; Peer reviewed