[Effects of transgenic Bt rice on soil dissolved organic carbon and nitrogen contents and microbiological properties].

A two-year field experiment (2009 and 2010) was conducted to evaluate the effects of three transgenic Bt rice lines (KMD, HH1, and BtSY63) and their non-Bt lines (XSD, MH63, and SY63) on soil dissolved organic carbon (DOC) and nitrogen (DON) and microbiological properties. All the measured indices changed significantly with sampling time. Comparing with their corresponding non-Bt lines, the test transgenic Bt lines had little effects on the soil DOC, DON, and microbial biomass nitrogen (MBN). The transgenic Bt lines had significant effects on the soil microbial biomass carbon (MBC), basal respiration (BR), and microbial metabolic quotient (qCO2) in certain periods of time in the first year, but no effects in the second year. Among the soils planted with the three non-Bt rice lines, no difference was observed in the DOC, DON, and microbiological properties, whereas in the soil planted with BtSY63, the MBC and BR were significantly higher, but the qCO2 was significantly lower, as compared with those in the soils planted with KMD and HH1. In sum, two years' planting transgenic Bt rice had little effects on the soil DOC, DON, and microbiological properties, but the differences of soil microbiological properties induced by the planting of different transgenic Bt rice lines were larger than those induced by the planting of different non-Bt lines, implying that long term monitoring would help to reveal the effects of transgenic Bt rice on the structure and function of soil ecosystem.

[Effects of two years planting transgenic Bt rice (BtSY63) on soil nematode community].

A two-year field experiment was conducted to evaluate the effects of planting transgenic Bt rice (BtSY63) and its near-isogenic non-Bt rice (SY63) on the soil nematode abundance, trophic group composition, ecological indices, and community structure. With the planting of BtSY63 and SY63, the soil nematode abundance changed obviously with sampling time, but had no significant difference between planting BtSY63 and SY63. Only at specific sampling time, the percentage of omnivore-predators and the Shannon diversity index of nematode community under the planting of BtSY63 were significantly higher than those under the planting of SY63. The non-metric multidimensional scaling (nMDS) of nematode community revealed that no significant difference was observed in the nematode community composition between planting BtSY63 and SY63 across all sampling times. In conclusion, two years planting BtSY63 had no deleterious effects on the soil nematode community.