Contribución de surcos y cárcavas efímeras a la producción de sedimentos y fósforo en una cuenca agroforestal

Resumo

This work examines the evolution of the concentrations of sediment suspension (SS) and particulate (PP) and dissolved phosphorus (PD) during four runoff events in a small stream that drains an agroforestry catchment (NW Spain). Both the SS, as the PP and DP were increase during the events. The highest concentrations were reached before the fl ow peak, excluding DP concentrations that were obtained after the fl ow peak probably associated with the subsurface fl ow. The PP, which represents more than 80% of total, showed a signifi cant correlation with SS in all events. Suspended sediment and PP maximum concentrations as well as SS and PP load showed marked differences between events. Suspended sediment exported ranged between 19.66 and 483.23 kg/km2, while the PP varied between 0.03 and 0.41 kg/km2. Rills and ephemeral gullies developed in cultivated land were the main sources of sediment delivered to the stream.