DATOS PARA EL DESARROLLO DE UNA RED INTEGRADA DE SEGUIMIENTO DE LA CALIDAD DE SUELOS EN GALICIA (N.O. DE ESPAÑA): BALANCES GEOQUÍMICOS EN SUELOS FORESTALES (Pinus radiata). 1. APORTES DE ELEMENTOS POR DEPOSICIÓN ATMOSFÉRICA Y HOJARASCA.
M.X. GÓMEZ-REY, R. CALVO DE ANTA
Dpto. de Edafoloxía e Química Agrícola. Fac. de Bioloxía,Univ. de Santiago de Compostela. 15782-Santiago de Compostela.
study of the balances of the principal elements in a Pinus radiata D. Don forest
system was carried out during two consecutive years (1997/8), in a forest plot
situated in the centre of Galicia (Alto de O Martelo, A Coruña, NW Spain).
The aim of the study was to obtain data that would allow reference levels to
be established for monitoring the quality of forest soils in mountainous regions
of Galicia, both with and without anthropogenic influences.
The chemical composition of the solutions entering the system reflected a strong marine influence, accounting for 85% of the ionic load and an acid-base status close to equilibrium of pure CO2-H2O. There was an increase in acidity after passing through the forest canopy, particularly in the stemflow, for which a mean pH value of 4.1 was obtained; there was also an increase in the concentration of certain elements, such as Mg, NO3 and SO4. The return of elements via litter is the basic route of entry of PO4, NO3 and Al, whereas Na and K mainly originate from deposition; the amounts of Ca, Si, Fe and SO4 originating from both routes of entry are similar.
Key Words: biogeochemical budgets, forest soils, throughfall, stemflow