Factors affecting field-to-field variation in pesticide residue levels in Chinese cabbage and spinach

摘要

To find the effect of field-to-field variation in pesticide residue levels in Chinese cabbage and spinach, two residue datasets each were obtained from eight test fields in different years. Based on the obtained sixteen field datasets, the highest residue levels of five pesticides in Chinese cabbage and of three pesticides in spinach were 10.5 and 5.7 times higher than the lowest residue levels, respectively. The correlation of the pesticide residue levels in spinach samples between the data obtained in different years from the same six greenhouses was in good agreement (R~2=0.8138). In contrast, there was no clear correlation between the pesticide residue levels in Chinese cabbage samples, which were grown in open fields. This different tendency observed in the residue data may be because of the difference in growing conditions. In addition, each datum of the pesticide residue was negatively correlated with the sample weight.