Eutrophication — the increase of plant biomass due to addition of artificial or natural fertilizers, such as nitrates and phosphates — harms the environment in many ways. Yet, nitrogen fertilizer may also be positive for the environment as Hang Su and co-workers, Max Plank Institute for Chemistry, Mainz, Germany, show.
They found that nitrogen fertilizer indirectly strengthens the self-cleaning capacity of the atmosphere. Nitrous acid is formed in fertilized soil and released to the atmosphere. The amount released increases with increasing soil acidity. In the air, nitrous acid leads to the formation of hydroxyl radicals which oxidize pollutants, leading to their removal by rain.
Agricultural activities and land-use changes may strongly influence the oxidizing capacity of the atmosphere, an effect that has not previously been taken into account by geoscientists.
- Soil Nitrite as a Source of Atmospheric HONO and OH Radicals
H. Su, Y. Cheng, R. Oswald, T. Behrendt, I. Trebs, F. X. Meixner, M. O. Andreae, P. Cheng, Y. Zhang, U. Pöschl,
Science 2011.
DOI: 10.1126/science.1207687
