Influence of different herbicide dosages on the phosphatase and dehydrogenase activity in soil

In a laboratory experiment the influence of different dosages of herbicides on the activity of phosphatase and dehydrogenase in soil was determined. T he herbicides were applied alone and with addition of an adjuvant. The foll owing combinations were used: Triflurotox 250 EC (a.i. trifluralin), Triflu ralin 250 EC (a.i. trifluralin) with adjuvant, Trinap 400 SE (a.i. triflura lin and propachlor) with adjuvant, and Triflurotox 250 EC with Ramrod 480 S .C. (with proportion of trifluralin and propachlor like in in Trinap 400 SE ) without adjuvant. The results show that in presence of the adjuvant the a ctivity of acid- and alkaline phosphatase changes very slightly and only te mporary as compared with the influence of the herbicides alone. In soil ame nded with combinations of herbicides and adjuvant, the activity of dehydrog enase increases during the whole experiment, as compared with soil amended with the herbicides alone.