Multiple functions of buffer strips in farming areas

Buffer strips (BSs) are strips interposed between fields and streams that intercept and treat the waters leaving cropland, and so are a useful tool for reducing agricultural diffuse pollution in lowland areas. If properly vegetated and managed, they can also produce wood for burning, act as sinks for atmospheric CO2 and enhance the landscape beauty. The paper presents an analysis of the different functions of BS and reviews the more important data from research programmes conducted over the last decade in Veneto Region (North-East Italy). Over a period of 3-5 years, in two experimental sites, young BS reduced total runoff by 33%, losses of N by 44% and P by 50% compared to no-BS. A mature BS was able to abate both NO3-N and dissolved phosphorus concentrations by almost 100%, in most cases having exiting water that satisfied the limit for avoiding eutrophication. The BS also proved to be a useful barrier for herbicides, with concentrations abated by 60% and 90%, depending on the chemical and the time elapsed since application. Considering the CO2 immobilized in the wood and soil together, the different BS monitored stored up to 80 t ha-1 year-1 . The BS caused negligible disturbance to maize, soybean and sugarbeet yields. The hedgerows, par- ticularly if composed of trees taller than 6 m, positively influenced the aesthetic value of the territory, improving its perceived naturalness and screening the man-made elements. Lastly, through a multi-objective analysis, opportunity costs were estimated to support the public decision-maker in determining the subsidies to be paid to encourage farmers to plant BS.