| Abstract: | During the last 50 years substantial tracts of the Italian badlands have been reclaimed for arable cultivation. It is a process that involves modelling the degraded clay landscape with bulldozers, often resulting in steep, unstable slopes. This work investigates the stability of reclaimed land in these erosion susceptible environments. Aggregate stability is used to assess the soil's erodibility with the aim of determining those physicochemical properties that govern the potential for erosion. Regression analysis demonstrates that the most significant variables in determining soil erodibility are the percentage of organic matter and the exchangeable sodium percentage (ESP). Threshold values of 1–2 per cent organic matter and 15 per cent ESP are presented above and below which, respectively, the soils attain a degree of stability. Reclaimed land is on the borderline of these thresholds and therefore represents a potential erosion hazard. However, the stability of reclaimed land was significantly higher than that of the badland parent material, ascribable to a decline in the ESP. The results are supported by a series of soil crust experiments using simulated rainfall in the laboratory. This investigation has implications for land management and landscape conservation. If the organic matter content of reclaimed land is maintained and the ESP reduced, then, when used in combination with other soil conservation techniques, erosion will be minimized. However, this implies that the badland landscape, and its diverse ecology and morphology, may have been permanently lost to agriculture and, as such, should be recognized as a threatened Mediterranean landscape. © 1998 John Wiley & Sons, Ltd. |
