Carbendazim Residues in the Soil and Their Bioavailability to Plants in Four Successive Harvests

In this work, long-term outdoor lysimeter investigations using C-labeled carbendazim (MBC) were carried out. At the start of the experiment a single application of MBC into the soil was performed, then barley as a test plant was sowed in four vegetative seasons. The disappearance of MBC in the soil comprised two phases. In the first phase, disappearance of extractable and the formation of bound residues occurred simultaneously. In the second phase, further degradation of both kinds of residues was observed. Approximately 33% of the applied radiocarbon was retained in the top soil layer, even four years after application (mostly ‘soilbound’). The residues taken up by plants depended mainly on the level of extractable MBC in the soil, but the residues in plants were detected as extractable and bound as well. In the barley harvested in the first growing season, the residues were the highest and were present in all parts of the plant. After the fourth season only barley roots were contaminated with bound residues.