BY：Arkadiusz Telesiński
Laboratory experiment was carried out on light dusty clay, into which two herbicides: Izoturon 500 SC (composed of isoproturon only) and Rokituron D 470 SC (composed apart from isoproturon of 2,4-D and dicamba), were introduced in the following doses: recommended field dose (FD), tenfold higher dose (10FD) and one hundredfold higher dose (100FD). The amount of isoproturon introduced together with Izoturon 500 SC and Rokituron D 470 SC was the same, which allowed for assessing the effect of 2,4-D and dicamba on the rate of isoproturon decay in soil as well as for evaluating the modification of changes in soil biochemical parameters induced by isoproturon introduction into it by 2,4-D and dicamba. During the experiment, the content of isoproturon and its metabolites: MDIPU, DDIPU and 4-IA, and of dicamba and 2,4-D in soil as well as the activity of catalase, dehydrogenase and nitrate reductase. Isoproturon DT50 in soil ranged between 9.7 and 18.5 days and rose together with a dose increase. MDIPU, i.e. the metabolite produced in result of the N-demethylation of isoproturon, was detected as early as on day 1 of experiment. Other determined metabolites were detected in successive measurement times. Moreover, isoproturon addition to soil decreased the activity of examined enzymes as well as the value of AEC. It was also found that 2,4-D and dicamba addition slowed down the rate of isoproturon decay in soil as well as intensified the inhibition of nitrate reductase and dehydrogenase activity in soil and levelled the inhibition of catalase activity in soil induced by isoproturon.Basing on the carried out research work, it can be stated that the best indicator of soil contamination with isoproturon appears to be the AEC value, which was negatively correlated with the content of isoproturon and MDIPU in soil, with the content of these compounds amounting respectively to 40 mg kg-1d.w. soil and 2.2 mg kg-1d.w. soil when the value of AEC decreased rapidly.
Yangzhou pioneer chemical CO.,LTD
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