Researchers from the Chinese Academy of Sciences and partners conducted a
global meta-analysis examining the responses of soil enzymatic activity to
Bt crops. The results are published in the Science of the Total Environment.
The researchers initially quantified the responses of soil enzymatic
activity to Bt crop cultivations with or without Bt residues incorporation.
Then they explored how the responses of soil enzymatic activity varied
across Bt crops or in different growth periods, and revealed the relative
contributions on the responses.
Results showed that dehydrogenase and urease generally positively responded
to Bt crops. Dehydrogenase, which reflects the total metabolic activity of
viable soil microbes, when significantly increased, may result in a higher
rate of soil organic matter mineralization or the transformation of organic
nutrients and nutrients into inorganic forms. Urease, one of the enzymes
participating in nitrogen mineralization, when increased might lead to
boosting the nitrogen cycling. It was observed that significant responses
usually appeared under Bt cotton or in middle growth stages. It was also
reported that the enzymatic responses attributed more to Bt crop properties
than to soil properties.