Effects of Metribuzin on the abundance and activity of some groups of soil microorganisms
Effects of the metribuzin herbicide on soil microorganisms were investigated Trials were set up on a chernozem soil in laboratory environment. Metribuzin application rates were 0.3, 0.6, 1.2 and 2.4 mg a.i./500g air-dry soil at 10?C, 20?C and 30?C. Soil respiration (amount of released CO2) and abundance of total microflora, fungi, actinomycetes, cellulolytics, ammonifiers nitrifiers, aerobic nitrogen fixiers (Azotobacter) and anaerobic nitrogen fixiers (Clostridium) were studied. Metribuzin was found to inhibit soil respiration, causing statistically highly significant changes of that area of microbiological activity in almost all trial variants. The effect of metribuzin on microorganism abundance varied. It caused a decrease in total microflora, fungi, cellulolytics, nitrifiers, and aerobic and anaerobic nitrogen fixiers (Azotobacter and Clostridium) at all temperatures, and reduced the abundance of actinomycetes at 10?C and 30?C. No effect on ammonifiers was recorded.