Spatial variability of soil properties at different scales within three terraces of the Henares River (Spain)

This paper applies statistical and geostatistical procedures to a soil chronosequence on the terraces of the Henares River (NE Madrid) to analyse the spatial distribution of several soil properties and use the contribution of geostatistics to establishing a landscape evolution model of the area. Particle-size distribution, pH, calcium carbonate and organic carbon were analysed. Statistical procedures focus on analysing differences between terraces. Geostatistical procedures identify short- and medium-range variations within individual terraces at different scales. Standard transitive variogram models describe the properties of the younger terrace;whereas the linear intransitive model fits the majority of variograms of the older terrace. The analysis confirms and quantifies the decrease in variability of soil properties from young to old deposits, showing thus an increment of soil homogenisation with time. Ageing of the terraces causes the variables to show nontransitive variogram models with unbounded variances within the observation range. (C) 1998 Elsevier Science B.V. All rights reserved.