Influence of tillage systems on terbuthylazine degradation and leaching in the soil

Abstract

The aim of the study was to evaluate the effect of the cultivation system on the rate of degradation and movement of terbuthylazine in the soil. Model experiments were carried out on soil taken from the field, parts of which were differentiated for 3 years in terms of the cultivation system: conventional (with pre-winter ploughing), reduced (disk harrow + tillage unit) and zero tillage (no tillage – applica­tion of glyphosate-containing herbicide + direct sowing). The soil was collected with a Van der Horst core sampler into the columns. In a stationary spray chamber, a herbicide containing terbuthylazine was applied at the recommended dose of 500 g/ha. On the basis of the conducted research, it was found that terbuthylazine is a substance with medium persistence in soil (DT50 = 27–34 days). This substance shows the slowest degradation in soil with a zero tillage system. On the other hand, the lack of disturbing the soil structure has a positive effect on the mobility of the herbicide, allowing it to move faster outside the plant root zone.