Vegetated ditches for the mitigation of pesticides runoff in Po Valley

Risk mitigation measures for pesticides are increasingly important (EU Commission, 2009). Previous research (Pappalardo et al., 2015) showed constructed surface flow wetland can reduce the pollution of watercourses from watershed of hundreds of hectares in Northern Italy agro-systems. Indeed, in very fragmented landscapes as in Po Valley there is also an urgent need for the mitigation of agricultural runoff from a large number of small farms in order to intercept pollutants before they enter large watercourse, where mitigation is impossible. Vegetated agricultural drainage ditches, are common in Po Valley agricultural landscape, being traditional part of the field margin (Hackett and Lawrence, 2014), and even if they are mainly designed as drainage ways, they can provide two important ecosystem services: 1) habitats for wildlife and wild plants (Herzon and Helenius, 2008), and 2) runoff mitigation for the protection of watercourses (Vymazal and B?ezinovà, 2015). According to classification, the vegetated ditch is an "off-field mitigation measure" of runoff as it can reduce flow velocity, intercept and remove sediment, organic material, nutrients and chemicals carried in runoff water.