The effect of nicosulfuron on some physiological groups of microorganisms

Abstract

The effect of nicosulfuron on abundance of amino-autotrophs, amino-heterotrophs, Azotobacter sp., phospho-mobilizers and phospho-mineralizers was examined. A trial was set up in laboratory conditions on chernozem soil type. Nicosulfuron was applied in concentrations 0.3, 1.5 and 3 mg/kg soil. Sampling for analysis was done 1, 7, 14, 21, 30 and 60 days after atrazine application. The results showed that the effect of nicosulfuron depended on rates of application, duration of activity and group of microorganisms. Nicosulfuron had an inhibiting effect on Azotobacter sp., amino-heterotrophs, and phospho-mobilizers. Nicosulfuron inhibited amino-autotrophs initially, and stimulated them after the population recovered, while nicosulfuron had stimulating effect on phospho-mineralizers. However, the changes detected were found to be transient, and therefore there is no real risk of the compound disrupting the balance of biochemical processes in chernozem soil.

U radu je ispitivano kratkotrajno delovanje herbicida nikosulfurona na brojnost nekih fizioloških grupa mikroorganizama. Ogled je postavljen u laboratorijskim uslovima na zemljištu tipa černozem. Nikosulfuron je primenjen u količinama od 0,3, 1,5 i 3 mg/kg zemljišta. Praćene su neke fiziološke grupe mikroorganizama i to: aminoheterotrofi, aminoautotrofi, Azotobacter sp., fosfomineralizatori i fosfomobilizatori. Uzorci za analize uzimani su 1, 7, 14, 21, 30 i 60 dana posle primene nikosulfurona. Dobijeni rezultati su pokazali da je uticaj nikosulfurona na brojnost ispitivanih fizioloških grupa mikroorganizama zavisio od primenjene količine i dužine delovanja i da je bio stimulativan ili inhibitoran. Nikosulfuron je inhibitorno delovao na Azotobacter sp., aminoheterotrofe i fosfomobilizatore. Na aminoautotrofe je prvo delovao inhibitorno, a kasnije, zbog obnavljanja populacije, stimulativno. Na fosfomineralizatore nikosulfuron je delovao stimulativno. Međutim, utvrđene promene su bile prolaznog karaktera, tako da se može smatrati da nema realnog rizika od narušavanja ravnoteže mikrobioloških procesa u zemljištu pod uticajem ovog herbicida.