Farmland use data and remote sensing for ex-post assessment of CAP environmental performances : An application to soil quality dynamics in Lombardy

With the reform of the European Common Agricultural Policy (CAP) in 2013, subsidies to farms are now bound to the fulfilment of environmentally friendly measures, such as crop diversification and allocation of a share of their farmland to Ecological Focus Areas, the so-called “Greening requirements”. Research on the effects of these policy changes so far have focused mainly on land use transition; however, a detailed investigation of how CAP greening affects the properties of agricultural land is required to assess the actual environmental benefits of the reform. In this study, we present a first attempt to assess the impacts of CAP greening on selected soil quality indices in Lombardy, a populated region in northern Italy where high-intensity agriculture is widespread. We combine high resolution (10/30 m) soil indices from remote sensing based on Landsat-8 and Sentinel-2 data with a regional administrative database covering all agricultural parcels of the region. We then perform a correlation analysis to investigate whether and to what extent greening prescriptions affect the soil quality indices from 2014, representing pre-greening conditions, to 2017, representing greening conditions after 3 years of implementation. Our analysis indicates a high persistence of soil quality indicators and suggests that some crops might have a significant impact on soil quality dynamics, along with farm’s compliance with CAP greening. Although we identified some uncertainties in the soil indices, by integrating a large volume of data and an efficient processing algorithm our method paves the way for ex-post environmental performance assessment of agricultural policies.