Microcosm Studies on the Volatility of Pesticides from Soil Surfaces
- D. Lembrich,
- F. Beese and
- I. Scheunert *
A laboratory model was developed to investigate pesticide volatilization from soil surfaces under various boundary conditions. Carbon-14-1abeled terbutylazine (2-chloro-4-ethylamino-6-t-butylamino-1,3,5-triazine) was applied to the surface of different soils in doses commonly used in agriculture. The experimental setup was designed to study the dynamics of the volatilization process. Short sampling intervals give information about temporal changes in loss rates, which allows to quantify the influence of the application mode. Drop application, for example, leads to volatilization kinetics different from those by spraying, especially in the initial phase. Another aim of the experiments is to describe soil matrix effects on pesticide volatility. After a test period of 10 d the cumulative vapor loss ranged from minimum 6.9% (loamy sand) to maximum 23.1% (weakly loamy sand) of the applied 14C-terbutylazine. In the case of a silty loam it was shown that soil moisture had a strong effect on terbutylazine volatilization. Rising the soil water suction resulted in a drastic decline in volatility.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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