Study On Soil Microbial Response Characteristics Of Soda Saline-sodic Soil Improved By Rice Cultivation In Northeast China

In the context of the global food crisis,saline-sodic soil as an important land reserve resource for food production,play an important role in ensuring national food security.Therefore,the remediation and utilization of saline-sodic soil has become an important issue to be solved urgently in agricultural development and environmental management.Remediation saline soils by planting rice is an important way to realize the efficient utilization of soda saline-sodic soil resources in Northeast China,which has the dual function of restoring regional ecology and developing economy.At present,most of the research on the remediation of saline soils by planting rice focus on the change of the physicochemical properties and soil enzyme activities,but the research on soil microorganism is not deep enough.As an important index of soil fertility,soil microorganism plays an important role in the improvement of saline-sodic soil.Thus,in this study,we use the soda saline-sodic soils which remediated with different years of rice cultivation(0 year,2 year,5 year,6 year,10 year,15 year and 20 year)and the different dosage of biochar application(0,33.75t/ha,67.50t/ha and 101.25t/ha)after 3 years under rice growing condition as experimental materials,to analyzed the changes of bacteria and fungi by high-throughput sequencing.The aims of this study were assess the response of soil microbiome to saline-sodic soil improvement under the background of rice cultivation and provide theoretical guidance for the improvement of saline-sodic soil.The results were showed as follows:1.Rice cultivation significantly increased the relative abundance of Firmicutes,Chloroflexi and Zygomycota in saline-sodic soil,while significantly decreased the relative abundance of Actinobacteria,Gemmatimonadetes and Acidobacteria.The rice root exudates and plant residues recruited more microorganisms and increased microbial richness and bacterial diversity.At the same time,the microbial community structure significantly changed after rice cultivation,and the microbial community structure of saline-sodic soil was significantly correlated with soil p H,EC,SOC,TP,AP and MN.2.Different years of rice cultivation affect the interaction relationship and variation characteristics between bacteria and fungi in saline-sodic soil.The remediation of saline soils by planting rice increased the interaction betweenmicroorganisms,and with the increase of rice cultivation years,the interaction intensity of soil microorganisms increased at first and then decreased.3.The composition and relative abundance of bacteria and fungi in saline-sodic soil changed after 3 years of applying different dosage of biochar under rice cultivation.The addition of biochar had no significant impact on the bacterial diversity,but the diversity of fungi showed a tendency to decrease.At the same time,different biochar application dosage changed the community structure of bacteria and fungi in saline-sodic soil,and the community structure of bacteria and fungi were significantly correlated with MN.4.The interaction between bacteria and fungi in saline-sodic soil were changed after 3 years of different dosage of biochar applying under rice cultivation.When the biochar dosage was 33.75t/ha,the interaction between bacteria and fungi were stronger and it was suitable for the improvement of soda saline-sodic soil.