Nitrogen dynamics in volcanic soils under permanent pasture

In Terceira Island (Azores, Portugal), 87% of the agricultural land is used for permanent pasture under periodical grazing. The edaphoclimatic conditions promote nitrate leaching into the groundwater and runoff, which carries sediments and fertilizers into the surface waters. Of particular interest is the fact that volcanic Andosols are rarely study to analyze nitrogen dynamics. The soil capacity to provide mineral N from its organic matter pool...