Mobility and dissipation of cadusafos in banana fields in Martinique

Abstract

The behaviour in soil of the nematicide cadusafos ( S, S-di- sec-butyl O-ethyl phosphorodithioate) was studied in four banana fields for eight weeks in Martinique (French West Indies). Pluviometry and soil characteristics influenced the movement of cadusafos. Migration and dissipation of the compound varied in different soil types: the time necessary to observe 50% dissipation of the applied dose in the 0–25 cm layer varied from 9–10 days in sandy loam soils (volcanic regosol and andosol) to 18 days in kaolinite clay soil (ferrisol) and ∼ 30 days in montmorillonite clay soil (vertisol). Migration was also more rapid in sandy soils. Adsorption parameters ( K fa) were discussed using Freundlich equation and desorption parameters ( K 1, K 2 and Q adsn) were evaluated using a model with two compartments corresponding with two different energy levels. These parameters confirmed the respective propensity of each soil sample to retain the pesticide and could be correlated with some soil properties (sand or clay content, cation exchange capacity).