Changes in the sorption-desorption of fungicides over time in an amended sandy clay loam soil under laboratory conditions

摘要

Purpose The aim of this work was to study the temporal changes in the sorption-desorption of fungicides in a sandy clay loam soil amended with spent mushroom substrate (SMS) under controlled laboratory conditions and the influence that fungicides properties and soil characteristics have on these processes. Soil amendment with SMS is becoming a widespread management practice since it can effectively solve the problems of uncontrolled SMS accumulation and disposal and improve soil quality. However, when simultaneously applied with pesticides, SMS can significantly modify the environmental behaviour of these compounds. Materials and methods Sorption-desorption isotherms of metalaxyl, penconazole, pyrimethanil and iprovalicarb for unamended and amended vineyard soils from La Rioja (Spain) were obtained. Composted SMS (C-SMS) and fresh SMS (F-SMS) from cultivation of different mushrooms were used as amendments at 2 % and 10 % rates. Soil parameters (organic carbon (OC), dissolved organic carbon (DOC), humic acid (HA) and fulvic acid (FA)) and sorption (Kf, nf, Kd, Koc) and desorption (Kfd, nfd, H) parameters of fungicides were determined over 0, 6 and 12 months of soil incubation with SMS under controlled conditions. Results and discussion Addition of amendments to soil increased soil sorption capacity of fungicides. Kd values increased with the hydrophobic character of fungicides (metalaxyl