Effect of crop type and crop growth on atmospheric nitrogen deposition

Varying atmospheric nitrogen (N) depositions for different crops were observed at Bad Lauchstadt (Saxony-Anhalt, Germany) when using the ITNI system (ITNI = Integrated Total Nitrogen Input), which is based on the N-15 isotope dilution method. These differences were only partly explained by climatic influences. The effects of crops on the atmospheric N deposition measured by the ITNI system are discussed. For this purpose, data of six different plant species recorded in 1998 were re-analyzed. It was found that the airborne N input is closely correlated with the morphology and metabolism of crops. Daily atmospheric N depositions of 129.0-360.8 g per hectare were measured for the plant species used. The nutritional supply of plants, especially with N, is another factor of influence on the N input from the atmosphere which should be considered. To investigate this aspect, a pot experiment was conducted with the grass Lolium perenne at three different N levels. An increase in the airborne N uptake (corresponding to N fertilization) was observed as biomass production rose.