The objective of the proposal is to investigate the interaction between intensive animal production and neighbouring wooded nature reserves concerning the N-dynamics and specifically the mobility of ammonia. The N-deposition will be estimated and the N-transformations in the soil will be studied with the "15N isotope dilution technique" (delta 15N-measurements). This could lead to qualitative information about the N-balance, Critical loads, soil acidification, nitrate leaching and emissions of N2O and NO.