Colorless, odorless and tasteless gas (N = Nitrogenium), which makes up by far the largest proportion in the air at 78% volume. The German designation reminds that nitrogen "smothers" (extinguishes) flames. Among other things, the nitrogen compounds are of great importance amino acids. alkaloids, Ammonium (compound with hydrogen, most common source of fertilizer), enzymes, Nitrates and saltpetre. 95% of nitrogen in the soil comes in the form of organic compounds (Norg) in dead plant and animal matter humus, in living root mass and in soil organisms. Maximum is 5% mineral bound, already plant-available nitrogen (Nmin) in the form of ammonium (hydrogen compound) and nitrate = saltpeter (oxygen compound). The organic nitrogen compounds are not available for higher-quality plants. You first have to go through bacteria into ammonium and nitrate, which play an important role in plant growth. From the roots nitrates are preferably taken, which in the photosynthesis responsible for the development of cellular protein and chlorophyll.
Nitrogen is one of the most important nutrients and is the "engine" of plant growth par excellence. Simplified, one can say that nitrogen is responsible for the generation of leaf mass and rooting is used. It is quite common for deficiency symptoms. Especially on sandy soils with too little organic matter, as well as on wet soils with lack of oxygen, nitrogen deficiencies often occur. Further losses result from denitrification, in which nitrates are reduced by bacteria to gaseous nitrogen. This manifests itself by weak vigor and pale green to yellow-tinged small leaves. This will be the photosynthesis retarded and the leaf veins and petioles have a reddish discoloration. The grapes from nitrogen-poor vineyards may lack fermentable sugars and cause problems or sticking of the fermentation to lead. Nitrogen deficiency is also a cause of the wine error UTA (Atypical age tone).
However, too large quantities have a negative effect. The excess supply of nitrogen is manifested by dark green leaves and overgrowth, as evidenced by disproportionate thick and long internodes in annual wood. The vines often suffer from bad fruit set and tend to Verrieseln, In addition, the diseases stem necrosis and bunch rot (eg Botrytis). In the grapes are then too little sugar. pigments (Dyes) and phenols which may negatively affect the quality of the wine. The consequences are also high shares urea and histamine in the wine.
Too high nitrogen levels in the soil are also due greening balanced, as the set plants take up nitrogen and withdraw from the vine. The nitrogen content in the soil is determined by the Nmin or the EUF method detected. Due to the high nitrogen content is almost 50% urea the world's most important nitrogen fertilizer. In the fertilization play too legumes a certain role. Nitrogen is also called inert gas (Inert gas) used in tanks to the whitespace to refill and oxidation to prevent, as well as for that desulphurisation from grape by binding of sulfur dioxide used.