chlormequat chloride

mineralization

bound residues

extractable residues

soil

The aim of this study was to evaluate the mineralization rates of chlormequat chloride (CCC) in soils of different textures from measurements of ¹⁴CO₂ evolution over a period of 100 days. The level of extractable and bound residual ¹⁴C in the soils at the end of the experiment was also determined. The degradation pattern of CCC was similar in all soil types and degree of its mineralization ranged from 53.4 to 55.7% over a period of 100 days. This process in all soils was described by first-order kinetics and CCC was mineralized with a similar constant rate (k) on the level of 0.029-0.034 day^-1, and DT₅₀ ranged from 67.7 days for sandy soil to 71.0 days for silt loam soil. Evaporation was not significant in the removal of CCC from soils, and the total amount of ¹⁴C-volatile organic compounds recovered at the end of the trials was similar to the background level. The level of ¹⁴C-extractable residues was low and reached the maximum value of 7.2% of the introduced radioactivity for sand and sandy loam soils. Levels of 14C-bound residues were higher in all soil types. The highest value (39%) was obtained for silt soil, while in the remaining soils it was lower and ranged from 30 to 33.5% of the introduced radioactivity. The relatively large amount of bound residues of CCC is probably connected with a strong affinity for soil components despite of its high water solubility and potential to be leached.