Abstract: This paper studied the effects of applying different concentration (0, 030, 0 60, and 090 mg·kg-1) tetracycline on the soil enzyme activities and rape quality. The results showed that soil urease activity after applied 030, 060, and 090 mg·kg-1 of tetracycline and soil su crase activity after applied 090 mg·kg-1 of tetracycline were inhibited in the whole cultivating period, while the soil sucrase activity after applied 030 and 060 mg·kg-1 of tetracycline showed a trend of activation-inh ibition-activation. Soil proteinase activity showed a trend of inhibition-acti vation, and the extent and duration of the inhibition and activation had signifi cant positive correlations with tetracycline concentration (r=0950** ). Soil catalase activity showed activation first and turned to irregular then. The action duration of tetracycline on the activities of soil urease, catalase, sucrase and proteinase were 7 weeks, 6〖KG-*2〗-〖KG-*7〗8 wee ks, 7 weeks, and 6〖KG-*2〗-〖KG-*7〗7 weeks, respectively. At harvest time, the soluble sugar contents in rape leaves after applying 030, 060, and 090 mg ·kg-1 of tetracycline decreased dramatically by 9199%, 8792%, 9012% , while the soluble protein content increased by 2647%, 2813%, and 2322%, respectively, compared to the control.

Key words: loess sandy soil, root, canopy layer, hydrodynamics mechanism, soil resistance to erosion.