Soil solution fluxes and composition trends reveal risks of nitrate leaching from forest soils of Italy

摘要

Although acidification is a natural soil formation process, atmospheric emissions of nitrogen and sulphur have exposed forest ecosystems to accelerated anthropogenic acidification for many decades. In Italy nitrogen deposition loads are high, and among the highest in Europe. Data from the Italian ICP-Forests monitoring network have shown that nitrogen deposition increases tree growth, and consequently the organic carbon sequestration. However, the accumulation of nitrogen in the ecosystem could cause nutrient imbalances and contribute to soil acidification. Within this context, we investigated the temporal changes of atmospheric deposition and soil solution concentration in the Italian ICP-Forests using the non-parametric Seasonal Mann Kendall (SMK) test. Further, we applied input-output models, to evaluate the capabilities of the soil-forest system to retain deposited nitrogen and thus protect underground waters.