Análisis de la variabilidad temporal de la infiltración en un gradiente de degradación de usos del suelo en el Pirineo central

Abstract

[ES] Se analiza la capacidad de infiltración con respecto a las condiciones físicas superficiales (humedad y resistencia mecánica) de suelos en el Pirineo Central, considerando tres escenarios: bosque natural, campos abandonados y cárcavas. El estudio se ha realizado en tres cuencas experimentales (San Salvador, Arnás y Araguás) situadas en un contexto geográfico, geológico y climático similar. La información se ha obtenido mediante ensayos con un infiltrómetro de doble anillo entre otoño de 2008 y verano de 2009. Los resultados sugieren cierto efecto de las condiciones físicas previas sobre la capacidad de infiltración. Sin embargo, el uso del suelo y la orientación de las laderas (N‐S) se han revelado los factores más determinantes. Esto se relaciona con la variabilidad estacional del estado físico antecedente y su dinámica durante los ensayos. Las diferencias de la infiltración asociada a la orientación de las laderas incluso pueden superar a las observadas entre usos del suelo.

[EN] The infiltration capacity has been analysed related to the variation of surface physical conditions (moisture and mechanical r esistance) of soils from the Central Spanish Pyrenees, taking into account the most representative situations of land uses and vegetal covers. The study was carried out in three experimental catchments, each representative of different environments in terms of soil use and vegetation cover: forested (San Salvador), field abandonment (Arnás) and badlands (Araguás). The three catchment s are located near by and have similar geologica l and climatic conditions. The study was done through experimental infiltration s et s using a big double ring instrument (50 cm water column height. Experiments were performed from autumn 2008 to summer 2009. The infiltration process was analysed on six land uses situations: bare regolith, grass c overed regolith, north‐facing slope in forested soil, south‐facing slope in forested soil, north‐facing slope in meadow soil and south‐facing slope in pasture soil. Before and after each experiment soil was sampled in order to estimate moisture content (0‐1, 0‐5 and 5‐10 cm depth) and surface mechanical resistance was measured with the help of a pocket penetrometer, providing an idea a bout previous conditions and its variation. The results suggest a certain effect of moisture conditions on infiltration capacity. However, soil use and slope exposition (North and South) seem to be the most determinant factors. This is related to the seasonal variability of antecedent soil conditions and its dynamics during the experiments. The differences on infiltration capacity associated with slope e xposition can be higher than those observed between land uses.