Influence of PCNB on Enzyme Activities in Vegetable Greenhouse Soil

The influence of PCNB on activities of invertase, urease, neutral phosphatase and catalase in vegetable greenhouse soil was investigated. The results showed that the activity of invertase was influenced most markedly by PCNB of the experimental concentrations (10~150 μg·g-1). At 10 μg·g-1 of PCNB, the activity of invertase was stimulated during the beginning 15 days and was inhibited after 20 days, while at higher concentration (50,150 μg·g-1), it was inhibited all the time during the cultivating period (30 days), the more concentration of PCNB, the more strongly inhibition on invertase activity. The activity of urease was most strongly inhibited at 7th day by PCNB, but the effects were temporary and it could recover after 11 days, so the influencing process of PCNB displayed inhibition-stimulation-recover. There was no significant influence of PCNB on activities of neutral phosphatase and catalase, with a little change no higher than 10% of the activities of neutral phosphatase and catalase. Invertase was suggested to be the ecotoxicological index of PCNB in soils.