On the Content of Nitrogen in Atmospheric Precipiation in Sweden II

In the present paper an attempt is made to give a general idea of the geographical distribution of fixed nitrogen (NH₄-N) transferred to the soil through precipitation in Sweden. Further a map is given showing the distribution of α, a quantity proportional to the nitrogen concentration in the precipitation at the beginning of a rain and, it is assumed, representative for the content of fixed nitrogen in the atmosphere before the rain is falling.

A discussion of different causes of the concentration of fixed nitrogen in precipitation is presented and a photochemical process is suggested, which would explain the almost constant ratio between NH₄-N and NO₃-N frequently found within the temperate zones. It is evident, however, that other causes also are at work, especially at lower latitudes. The need of laboratory experiments is emphasized.