The Effects of Cu,Cd,Pb and Zn on the Activities of Urease,Protease and Peroxidase in Acid Cultivated Soil

The influence of Cu,Cd,Pb,Zn addition on the activities of urease,protease and peroxidase in an cultivated soil was studied by indoor incubation.The added dose is 50,100,200,400,600 mg·kg-1 for Cu,1,5,10,15,20 mg·kg-1 for Cd,100,300,500,800,1 200 mg·kg-1 for Pb,50,100,200,400,800 mg·kg-1 for Zn,respectively.The results showed that Cu,Cd,Pb and Zn mainly inhibited the activity of urease of which the inhibition effect decreased in the order of CuCdZn≥Pb.The inhibition of the four metals on the the activity of urease weakened during the final incubation period.The activity of protease was decreased dramatically in the early 17 days of incubation by adding the four metals and maintained the low activity afterwards.The four metals showed relatively weak inhibition effects on the activity of peroxidase except for Zn which markedly decreased the peroxidase activity in the early three days.The above results suggested that the activity of urease could be the indicator of soil Cu pollution,that of protease could be the indicator of Cu,Cd,Pb and Zn pollution of soil,and that of peroxidase could only indicate short-term Zn pollution of soil.