Edafología. Volumen 7-3. Septiembre 2000. pág 267-274.
Adsorption of two fungicides, penconazole and metalaxyl, with different hydrophobic character by 19 vineyard soils from the La Rioja region with low organic matter content has been studied. The adsorption isotherms were found to conform to the Freundlich adsorption equation. The Kf adsorption constant values for penconazole, compound more hydrophobic, range between 10.3 and 64.4 and they are higher than these of the compound less hydrophobic, metalaxyl (0.01-1.52). Simple correlations between adsorption constants and soil characteristics indicate that the organic matter is the only parameter influencing the adsorption of both compounds. The results indicate different adsorption of two fungicides by the soils studied. The affinity of penconazole by the organic matter is higher than that of metalaxyl. According to the retention by the soil will be higher and the vertical leaching will be more difficult than that of metalaxyl.
Key words: adsorption, fungicides, metalaxyl, penconazole, soils