| In this paper,the effects of transgeninc maize planting on abundance dynamics and community composition of soil nematodes were studied through crushed-straw-return cultivation and livestock manure returning after feeding corn flour in phytase transgenic(cv.BVLA430101)and nontransgenic maize fields in combination with potted experiment.In this way,it was carried out to scientificly assess soil ecological risks of transgenic maize after planting from the view of community,and service for the evaluation of soil ecological safety of phytase transgenic maize..And it is further to clarify the soil environmental safety of transgenic crops.The main results of this paper are as follows:1.Effects of crushed-straw-return cultivation of the conventional maize on abundance dynamics and community composition of soil nematodes under field conditionIn this study,a field experiment was carried out to study the impacts of crused-straw-return cultivation in contrast to straw nonreturn on abundance dynamics,genera and structure of the soil nematodes community.The results indicated that:Compared with straw nonreturn,crused-straw-return cultivation decreased the percent of plant-parasites and fungivores,while obviously enhanced the percent of bacterivores and omnivores-predators,and with a significant increase in the percent of bacterivores.Moreover,the total number of nematodes was higher in the crused-straw-return cultivation field than that of straw nonreturnfield.In addition,significant increases in the abundance of bacterivores were found for the treatment of crused-straw-return cultivation in relative to straw nonreturn.It indicates that the crused-straw-return cultivation can enhance the abundance and genera diversity of the soil nematodes.On the other hand,it can improve the soil environment and make the soil ecosystem to be stable and healthy.2.Effects of crushed-straw-return cultivation of phytase transgenic maize on abundance dynamics and community composition of soil nematodes under field conditionThe results showed that the crushed-straw-return cultivation didn't markedly affect the total number of soil nematodes and the abundance dynamics of the four trophic groups of plant-parasites,bacterivores,fungivores and omnivores-predators,and It didn't markedly affect the percentage-composition dynamics of the four trophic groups of soil nematodes compared with the straw nonreturn cultivation in the fields of phytase transgenic maize.Mireover,the results indicated that the crushed-straw-return cultivation significantly enhanced the Richness index(S)and the Shannon-Wiener index(Hhic groups of soil nematodes compared with improve the soil environm Channel Ratio index(NCR),the Total Maturity index(e Shannon-Wiener index(Hhic groups of soil nematodesstraw nonreturn cultivation in the fields of phytase transgenic maize..The Community Evenness(J)and the Nematode Channel Ratio index(NCR)were not changed with the extension of crushed-straw returning time,but the J and NCR values of the crushed-straw-return cultivation were higher than those of the straw nonreturn cultivation.In summary,the crushed-straw-return cultivation of phytase transgenic maize didn't markedly affect community composition and structure of on the soil nematodes,and it can improve the soil environment and make the community structure more healthy.compared with the straw nonreturn cultivation,3.Effects of manure returning cultivation after livestock feeding corn flour of phytase transgenic maize and conventional maize on soil nematodes The results showed that:(1)For the same cultivation of livestock manure returning,the phytase transgenic maize planting significantly increased total nematodes' abundances and the abundance dynamics of four trophic groups of plant-parasites,bacterivores,fungivores,omnivores-predators cropped with the conventional maize planting.(2)In the condition of planting phytase transgenic maize,the manure returing after livestock feeding phytase transgenic corn flour in contrast to conventional corn flour significantly decreased the percentage-composition of soil bacterivores.In the condition of planting conventional maize,the manure returing after livestock feeding phytase transgenic corn flour in relative to conventional corn flour also obviously decreased the percentage-composition of plant-parasites,while enhanced the percentage-composition of bacterivores.By two-factor ANOVA It showed that the manure returing after livestock feeding corn flour of phytase transgenic and nontransgenic maize could significantly enhance the percentage-composition of plant-parasites and bacterivores by two-factor ANOVAs.(3)In condition of planting transgenic phytase maize,manure returing after livestock feeding phytase transgenic corn flour didn' t markedly affect the Shannon-Wiener index(H'),the Evenness index(J)and the Nematode Channel Ratio index(NCR);in condition of planting convenditional maize,manure returing after livestock feeding phytase transgenic corn flour significant increased the Richness index(S),but it didn't markedly affect the values of H',J and NCR.It showed that manure returing after livestock feeding corn flour of phytase transgenic and nontransgenic maize can significantly enhance the percentage-composition of plant-parasites and bacterivores,and significantly influence the richness index of soil nematodes' community.The rational manure returning cultivation could provide a rich source of carbon for soil microbes,and increase the richness of families and generas of soil nematodes' community.In summury,the curshed-straw-return cultivation,and manure returning after livestock feeding corn flour of phytase transgenic maize or nontransgenic maize both significantly increase the abundances of soil nematodes,and enhance the bacterivores' number while decrease the percentage-composition of plant-parasites.And it is presumed that the above cultivations don't markedly affectthe composition and structure of soil nematodes'community,and simultaneously can enhance the abundance and genera diversity of the soil nematodes,finally improve the soil environment and make the soil ecosystem to be much more stable and healthy. |
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