Changes in soil properties and bacterial community during flooding and drainage periods under different rice planting modes
To study the effects of different rice planting modes and water management on soil properties and microorganisms in paddy fields,long-term monitoring experiments including single cropping rice with and without fertilization and tobacco rice rotation were used to analyze the changes in soil physical and chemical properties and microbial community structure during flooding and drainage periods of rice growth.The results showed that soil organic matter and total nitrogen levels were increased by 32.88%-34.79% and 38.22%-44.39%,respectively,under the tobacco rice rotation mode compared to those under the single cropping rice mode.During the flooding period,total dissolved nitrogen in the paddy soils mainly comprised dissolved organic nitrogen,accounting for 56.06%-62.54% .During the drainage period,nitrate nitrogen was the main form,accounting for 62.34%-74.05% .The levels of dissolved organic nitrogen and ammonium nitrogen in paddy soil under the tobacco rice rotation mode significantly increased during flooding and drainage conditions,but the change in nitrate nitrogen content was not significant.Compared to the single cropping rice treatment,the tobacco rice rotation mode improved the Sobs,Shannon,and Ace indices of bacteria in the paddy fields.Acidobacterium and Xanthobacter were both dominant in the three rice planting modes.There were significant differences in Thermodesulfovibrionia and Syntrophorhabdus during flooded conditions among the three rice planting modes,and there were also significant differences in Nitrospira under drainage conditions.The absolute abundance of pomA under the tobacco rice rotation mode decreased by 18.45% to 18.54% than that under the single cropping rice treatment.In conclusion,there were significant differences in soil dissolved nitrogen composition and bacterial community structure between the flooding and draining stages.Compared with the single cropping mode,the rotation mode of tobacco rice could improve soil fertility and microbial community structure,increase the abundance of sulfate-reducing bacteria,and reduce the abundance of mcrA genes.
国家科技期刊平台
NSTL
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