Land-use and land degradation processes affecting soil resources: Evidence from a traditional Mediterranean cropland (Greece)

Land degradation is a complex process resulting from the permanent interaction between physical and human factors. The effect of changes in land-use and land management on soil erosion and desertification risk has been studied in Messara Valley (Crete, Greece) over the last six decades (1950–2010). Vegetation cover and land-use have been analyzed using representative aerial photographs and ortho-photomaps for representative dates. Soil attributes have been described in a semi-detailed survey in 2010. Soil erosion rates and desertification risk have been assessed for each period using the PESERA and TERON models and the MEDALUS methodology, respectively. Based on distinct socio-ecological characteristics of the area three major time intervals have been identified. Cereals extensively cultivated during the first time interval were progressively replaced by olive plantations and vineyards in the following periods. Soil erosion due to water runoff was important especially in the olive transition period, declining in the olive subsidy period. However, tillage erosion became an important degradation process especially in the olive subsidy period due to mechanization of the agriculture determining soil losses ranging from 0.5 to 30 cm in sloping areas. Desertification risk due to soil erosion and land characteristics has significantly increased during the olive subsidy period.