Spatial and short-term temporal variations in runoff, soil aggregation and other soil properties along a Mediterranean climatological gradient

Physical and chemical soil properties were measured along a mountainous climatological gradient in the province of Alicante (Spain). The objective was to evaluate how the climate affects certain soil properties at different temporal and spatial scales. These properties include infiltration, runoff and sediment concentrations resulting from rainfall simulation experiments performed in winter and in summer. Chemical soil properties like carbonate content, organic matter content and CEC were analysed in reference soil profiles along the gradient. Physical soil properties like soil moisture content, macroaggregation and waterstable microaggregation were measured at monthly intervals during a year. The comparison of the results was done at different spatial (site, slope and patch) and temporal (monthly and seasonal) scales by means of some statistical tests. It can be concluded that there are some soil properties positively related to the gradient, like organic matter, clay content and CEC which increase with the annual rainfall. However, runoff coefficients and erosion are higher when the climatic annual rainfall. However, runoff coefficients and erosion are higher when the climatic conditions become more arid. Aggregation and infiltration capacity are higher on north-facing slopes and in vegetated patches than in south-facing slopes and in bare patches. (C) 1998 Elsevier Science B.V. All rights reserved.