Temporary ditches are effective in reducing soil erosion in hilly areas. An evaluation with the RUSLE model

Abstract

The European Cross-Compliance mechanism set up within the Common Agricultural Policy provides support payments to farmers under the condition that specific Standards for Good Agricultural and Environmental Conditions (GAECs) are respected. GAEC standard 5 is specific to limit soil loss by erosion in arable crops and requires to comply with the ‘Realization of temporary ditches’ in sloping lands affected by soil erosion. The evaluation of soil erosion with the Revised Universal Soil Loss Equation (RUSLE), performed in 60 hilly areas of Italy located in 11 administrative regions, indicated the effectiveness of temporary ditches in reducing soil erosion. As average the presence of ditches significantly decreased erosion by 22.6 Mg ha–1 yr–1 (67%) compared to erosion without temporary ditches. The highest soil losses in the presence of temporary ditches were found in Marche (24.1 Mg ha–1), Umbria (17.4 Mg ha–1), and Emilia-Romagna (15.3 Mg ha–1) regions, which were much above the USDA maximum acceptable erosion rate. Instead, the lowest soil losses were observed in Apulia (1.6 Mg ha–1), Molise (4.1 Mg ha–1), and Tuscany (5.9 Mg ha–1), where they assumed values below the USDA acceptable limit. Results pointed out that the topographic factor has the highest weight among the RUSLE parameters, thus its appraisal requires the best accuracy for a correct estimation of soil losses. Highlights - Temporary ditches significantly decreased erosion by 67%. - Highest soil losses in Marche, Umbria, and Emilia-Romagna regions are above the maximum acceptable erosion rate. - The lowest soil losses are in Apulia, Molise, and Tuscany. - The topographic factor has the highest weight among the RUSLE parameters. - Cross-Compliance measures can be coupled with conservation tillage.

Keywords

• Common Agricultural Policy
• cross-compliance
• Italy.