Effects of Modifiers on Soil Enzyme Activity at Different Growth Stages of Rice Plants under Zinc and Chromium Stresses

To study the effects of modifiers on heavy metal accumulation of rice plants under zinc and chromium stresses, pot experiments were used to study the effects of modifiers (lime, superphosphate, wheat straw, rape straw and rabbits´ feces) on soil enzyme activity at different growth stages of rice plants. The results showed as follows: The improvement of soil enzyme activities by different modifiers were high concentration > low concentration > CK at different growth stages of rice plants. The best modifier on soil catalase activity was high concentration rabbits´ feces which were 30.25%, 31.1% and 26.8% higher than CK at different growth stages of rice plants. At the same time, the best modifier on the soil urease activity was high concentration rabbits´ feces which was 48.98%, 38.28% and 31.53% higher than CK. The best modifiers on soil amylase activity was high concentration of rabbits´ feces (tillering stage of rice plants) and wheat straw (booting and filling stages of rice plants), which were 51.43%, 50% and 58.33% higher than CK.