U poljoprivrednoj proizvodnji dušik je vrlo često osnovni ograničavajući čimbenik rasta i razvoja biljaka, a s time i postizanja optimalnih prinosa. Najveće zalihe ovog elementa nalaze se u atmosferi, gdje je dušik u molekularnom obliku kojeg biljke nisu u mogućnosti usvojiti i iskoristiti. Nedostupan dušik iz atmosfere se kroz proces fiksacije veže u nove spojeve te na taj način postaje dostupan mikroorganizmima i biljkama da ih iskoriste za svoje metaboličke potrebe. Simbiotska fiksacija dušika najznačajnija za poljoprivrednu proizvodnju nastaje kao rezultat simbiotskih interakcija između
kvržičnih bakterija i leguminoza, nakon čega slijedi infekcija i nodulacija. U kvržicama, uz prisutnost enzima nitrogenaze dolazi do procesa fiksacije dušika u kojem se atmosferski dušik prevodi u amonijak kojeg biljka dalje uključuje u svoj metabolizam te ga iskorištava za svoje raznovrsne potrebe. U ekološkoj poljoprivrednoj proizvodnji koja je koncipirana na način da teži očuvanju prirode i okoliša, jedno od osnovnih načela je sjetva leguminoznih usjeva jer na taj način poljoprivredno tlo obogaćujemo dušikom te potičemo povećanje i održanje njegove plodnosti što u konačnici donosi mnogostruke pozitivne ekonomske i ekološke učinke.In agricultural production nitrogen is the main limiting factor for growth and development of plants and thereby also achieving optimum yield. The largest stock of this element is in the atmosphere, where nitrogen is in a molecular form which plants are not able to uptake and use. The proceesses of nitrogen fixation are defined as processes in which unavailable nitrogen from the atmosphere is transformed into new compounds, and thereby becomes available to microorganisms and plants to use them for their own metabolic needs. Symbiotic nitrogen fixation which is of the greatest importance for agricultural production occurs as a result of symbiotic interactions between the plants from the family Leguminosae and root nodule bacteria. Symbiotic interaction begins by mutual recognition of appropriate rhizobia and legumes, followed by infection and nodulation. In the nodule, with the presence of nitrogenase enzyme, the process of nitrogen fixation occures in which atmospheric nitrogen is transformed to ammonia which plant can include in its metabolism and use it for their various needs. In organic farming, which is
designed to preserve the nature and environment, one of the basic principles is cultivation of legume crops. In this way agricultural soil is enriched with nitrogen, stimuling increase and maintainance of soil fertility which has multiple positive economic and environmental effects
