Determination of Metribuzin-VP Leaching and Its Effect on the Microbiological Activity of Sandy Loam Soil


N. Poushkarov Research Institute of Soil Science and Agroecology, BG-1080 Sofia, Bulgaria


PETKOVA, D. and R. DONKOVA, 2000. Determination of metribuzin-VP leaching and its effect on the microbiological activity of sandy loam soil. Bulg. J. Agric. Sci., 6: 427-431

The leaching of the herbicide metribuzin (Zino) in sandy loam soil columns was studied with simulated rainfall of 100 mm as well as its effect on soil microflora. Metribuzin was applied in two doses: 80 and 160 g/dka*. Metribuzin leaching was established by the depth of soil columns in the following layers: 0-10 cm, 10-20 cm, 20-30 cm and 30-45 cm.
It has been established that when applied in a dose of 80 g/dka, metribuzin movement is limited to 20 cm and in a dose of 160 g/dka - to 45 cm. No residual quantities of metribuzin were established in the filtrates.
A negative effect on the quantity and activity of soil microflora has been observed immediately upon the herbicide application. Metribuzin has a strong negative effect on cellulose degrading microorganisms and actinomycetes, which could serve as indicators of soil contamination with this herbicide.

Key words: microbiological activity, sandy loam soil, soil contamination, herbicide, metribuzin-VP