Nitrogen fertilizers and soil fertility

Abstract

Soil fertility is of the most importance in organizing successful plant production and gaining high yield. Protection and preservation of soil fertility are of a high relevance in contemporary agriculture, since inadequate production technology and particularly the application of high doses of fertilizers very often leads to degradation processes and soil damage. The most common mistake is the overdose of nitrogen fertilizers. Therefore, in order to research the changes of basic agro-chemical traits of soil, the increased doses of nitrogen in carrot growing have been researched. The experimental part of the research was performed on sandy loam cambisol, with the following applications of nitrogen: 0, 60, 120 and 180 kgN/ha through KAN fertilizer. After carrot harvesting, the content of humus, phosphorus and potassium decreased, while the content of nitrate nitrogen was directly dependent of growing nitrogen doses. The lowest average content of NO3-N was determined in control (24.7 mg/kg), and the highest by applying 180 kgN/ha (47.0 mg/kg).

Plodnost zemljišta predstavlja jedan od najvažnijih faktora za uspešnu biljnu proizvodnju i postizanje visokih prinosa. Zaštita i očuvanje plodnosti zemljišta predstavlja najvažniji zadatak i aktuelan problem poljoprivredne struke, jer neadekvatnom tehnologijom proizvodnje, a posebno primenom visokih doza đubriva veoma često dolazi do degradacionih procesa i oštećenja zemljišta. Najčešće greške se javljaju prekomernim korišćenjem azotnih đubriva, pa je u cilju ispitivanja promena osnovnih agrohemijskih osobina zemljišta ispitivan uticaj rastućih doza azota pri gajenju mrkve. Eksperimentalni deo istraživanja izveden je na zemljištu tipa smonica u ogajnjačavanju, sa primenom doza azota: 0, 60, 120 i 180 kgN/ha kroz prihranjiavnje sa KAN-om. Nakon vađenja mrkve, sadržaj humusa, pristupačnog fosfora i kalijuma se smanjio, dok je sadržaj nitratnog azota pokazao direktnu zavisnost od rastućih doza azota. Najmanji prosečni sadržaj NO3-N je utvrđen na kontrolnoj varijanti (24.7 mg/kg), a najveći primenom 180 kgN/ha (47.0 mg/kg), što je u okviru dozvoljenih vrednosti.