The Effect of Land Management Practices on Soil Quality Indicators in Crete

The effects of four main practices tillage versus no-tillage, and intensive grazing versus extensive grazing, applied in characteristic agricultural and grazing lands of Crete Island were evaluated in situ using nine soil quality indicators. The following nine representative indicators of soil quality were evaluated using the rapid visual assessment methodology adopted at European level in the context of the EU research project iSQAPER: susceptibility to water and wind erosion, surface ponding (under cropping), formation of tillage pan, soil color, soil porosity, soil structure, susceptibility to slaking, infiltration rate, and biodiversity status. These indicators were measured in 48 agricultural field-plots to adequately represent the four above-mentioned practices and the different types of geomorphological patterns existing in the area. Additionally, 38 agricultural fields were sampled in the topsoil to assess cultivation practices (tillage, no-tillage) on soil organic carbon, cation exchange capacity, exchangeable potassium, available phosphorous, and soil aggregate stability. Based on the indicators rating methodology, the appropriate statistical tests were applied and the soils under different managements were characterized in terms of their potential quality and their general agricultural value. The obtained data showed that in agricultural areas, significant differences were detected between tillage and no-tillage management practices for the indicators of soil structure and consistency and infiltration rate. In grazing land, significant differences were found for the soil quality indicators of susceptibility to erosion and infiltration rate for the corresponding practices of intensive and extensive grazing. Organic carbon content, exchangeable potassium content and aggregate stability were greatly affected in tillage versus no-tillage management practices.