田间条件下转Bt水稻种植及秸秆还田对土壤酶、呼吸和土壤微生物功能多样性的影响

With the development of transgenic crops, there is an increasing concern about the possible adverse effects of their vegetation and residues on soil environmental quality. To evaluate the effect of vegetation of transgenic Bt rice followed by return of rice straw on microbe-mediated functions in soil under field conditions, two Bt transgenic rice lines, Huachi B6 (Bt-HC) and TT51 (Bt-T), were adopted to assess the possible effect on soil enzyme (neutral phosphatase, urease, catalase, and invertase) activities, anaerobic respiration activity, and microbial utilization of carbon substrates. The results indicated that the vegetation of the two transgenic rice lines, Huachi B6 (Bt-HC) and TT51 (Bt-T), and addition of their straw have few adverse effect on soil enzymes and anaerobic respiration activity, compared to their parent and distant parent, although some transient or even significant differences were observed. The vegetation and straw amendment of Bt rice B6 (Bt-HC) and TT51 (Bt-T) did not appear to have harmful effect on the richness and evenness of soil microorganisms. The dominant population of soil microorganisms seemed to be more sensitive and altered temporarily by vegetation and straw amendment of Bt rice. This alteration is, however, smaller than that caused by vegetation and straw amendment of non-transgenic distant parental rice. No different pattern of impact duo to plant species was found between B6 (Bt-HC) and TT51 (Bt-T). It could be concluded from the results obtained in this study that vegetation of Bt rice and the return of its straw as fertilizer will not alter soil microbe-mediated functions.