AcknowledgmentsThis project was developed in the frame of the

AcknowledgmentsThis project was developed in the frame of the SMARTPARKS project funded by the FCT (Portugal) under the project reference PTDC/AAC-AMB/098786/2008. This research paper was partially developed on behalf of PF-670462 Post-Doctoral Research Project (M3.1.7/F/005/2011) lead by A. Gil and supported by the FRC/Azorean Regional Government. This study was partially funded by FEDER as part of the Operational Programme for Competitiveness Factors – COMPETE and also received National Funding from the FCT – Foundation for Science and Technology as part of the PEst-C/AGR/UI0115/2011 strategic project.We also wished to thank two anonymous referees for their valuable critics and suggestions.
RUSLE; GAEC; Stone walls; Grass margins; LUCAS; Contour farming
1. Introduction
The Common Agricultural Policy (CAP) is the main EU policy through which farmers are receiving incentives in the European Union (EU). In order to get those incentives, farmers must comply with “best practice” landuse management practices (named cross-compliance). The main component of cross-compliance is the farmer's obligation to keep his land under Good Agricultural and Environmental Condition (GAEC, 2009). This regulation requests the farmers to prevent soil erosion, conserve soil organic carbon and maintain soil structure. An option to assess the effect of GAEC on soil erosion reduction is based on the use of soil erosion risk models. At national scale, models based on the Universal Soil Loss Equation (USLE) are most commonly applied (Panagos et al., 2014a).