ABSTRACT
This chapter reviews the current knowledge on pesticides fate when applied to organic soils. Pesticide retention, the process controlling the fate and persistence of pesticides in soils, depends on key pesticides properties such as polarity and hydrophobicity, and on soil organic matter quantity and quality. Generally, pesticide 152retention is higher in soils where the organic matter is in a more decomposed stage, although contradictory results are reported. Pesticide retention by organic soils can be irreversible and produce bound residues. The long-term fate and environmental importance of bound residues in organic soils is unknown. Some processes that decrease pesticide concentration in organic soils, such as plant uptake, degradation, erosion, and leaching, are discussed. The overall persistence of pesticides in surface horizons is higher in organic than in mineral soils. This persistence is usually related to pesticide retention by soil components and can result in soil accumulation of some pesticides with time. The pesticides applied to organic soils can affect biochemical processes and microbial activities. Generally, the results reported show that the effects do not persist for a long period of time.
