D. PETKOVA and R. DONKOVA
N. Poushkarov Institute of Soil Science, BG-1080 Sofia, Bulgaria
PETKOVA, D. and R. DONKOVA, 2003. Determination of herbicide Metribuzin (VP-Zino) leaching and its influence on microbial activity in leached smolnitza (Vertisol). Bulg. J. Agric. Sci., 9: 287–290
Leaching of herbicide Metribuzin (Zino) and its influence on microflora has been studied in column experiment with leached smolnitza with simulated rain of 140 mm. Metribuzin is introduced with a dose of 1600 g.ha–1. Herbicide leaching was determined through the soil column at 0–10 cm, 10–20 cm, 20–30 cm and 30–45 cm. Samples for studying the microbial activity were taken from 0–10 cm and 30–45 cm soil column layers. It was established that the applied metribuzin with a dose of 1600 g.ha–1 has been accumulated mainly in 0–10 cm column layer (51.2 %), 32 % in 10–20 cm layer and 7 and 5 % were found in 20–30 and 30–45 cm layers, respectively. Residual concentrations of metribuzin in the leachate were not found. Immediately after introduction of metribuzin, a negative impact on the quantity and activity of soil microflora has been observed. Metribuzin had a strong adverse effect on actinomycetes, which can be used as indicators for soil contamination with this herbicide.