Establishing the payment for the ecosystem service of soil erosion control

Soil conservation strategies based on the mean annual value of the rainfall erosivity factor could not guarantee appropriate erosion control for intense rainfall events. In this paper, a new method to define soil loss tolerance at a regional scale, using the crop and management factor of the USLE, C, was applied for estimating the payment for ecosystem service (PES) of soil erosion control. PES is characterized by a target value PEStg corresponding to a post-intervention condition in which soil loss is equal to the tolerance value. The PES was estimated by three different scenarios: (1) only reducing the current C factor, or combining its reduction with that of the (2) support practice factor P or (3) slope length factor L. For Scenario 1, the analysis demonstrated that a drastic reduction of the C factor determines PES/PEStg >= 1 regardless of the investigated climatic conditions. For Scenario 2, when C and P factors are equally weighted, the payment is higher than the target value for slope-steepness <= 15%. Scenario 2 always yields a higher payment compared to Scenario 1. For Scenario 3, the reduction of the topographic factor can lead the PES over the target value. Although PES is generally considered effective for environmental policy, it should be allocated by targeting erosion-prone areas, where soil conservation is a primary objective. These areas experience soil loss greater than tolerable value, which usually lacks a solid scientific basis. By contrast, the proposed method, developed for the Sicilian region, is grounded in a scientific framework and is useful to support policymakers and public authorities in the informed design of economic incentives for farmers who convert their activities in order to preserve soil resources.