Improvement and Validation of the Throughfall Technique for Nitrogen Deposition Measurements to Forest Ecosystems

Summary

The throughfall technique cannot be used to estimate the dry deposition of ammonium and nitrate when the dry deposition is small because the two ions are lost in the canopy. A new phenomena partly explaining this loss is the conversion of inorganic nitrogen to organic nitrogen in the canopy and in the throughfall collectors if they are not kept dark. It is difficult to analyse the throughfall deposition of organic nitrogen because it is bound in particles and can also stick to the walls of the collector. The sampling technique will be investigated further using the addition of known amounts of inorganic nitrogen to the canopy.