Genotoxicity of Agricultural Soils after one year of Conversion Period and under Conventional Agriculture

Agricultural soils are often contaminated with genotoxic chemicals. Hence, transition to sustainable agriculture requires a conversion period. We performed a comparative evaluation of the soil genotoxicity in a field after one year of conversion and in a field under conventional agriculture, not located close to sources of pollution. Soil samples were taken from 0-20 cm and 20-40 cm depth. Allium cepa-test system was used for the cytogenetic analysis. The higher mitotic index and lower frequency of chromosome aberrations in the samples from the field in conversion period compared with the field under conventional agriculture are indicative of a decrease of the soil genotoxicity. A slight increase in the frequency of aberrant cells and a substantial decrease in the mitotic index in 20-40 cm soil layer from both fields were observed. Regarding the field in conversion this might be due to the presence of agrochemicals used in the previous years, and indicates the necessity of longer conversion period. The results showed that Allium cepa-test might be was used for monitoring of genotoxic pollution of the soils without preliminary extraction of the chemicals they contain.