| Xinjiang is China’s largest cotton-producing region.The environment of the cotton field has changed significantly because of continuous cropping and fertilizer application.Many studies have shown that soil characteristics are closely related to soil microorganisms,and microbiome big-data plays a decisive role in developing soil health evaluation indicators.However,the study of soil microbiome and soil health in the Xinjiang cotton field is still in infancy.The research on soil microbial diversity and community structure in the Xinjiang cotton field is insufficient,and there are few studies on the prediction of soil microbial community and function based on seasonal changes.There are insufficient soil microbial big-data,which cannot explain the interaction between environmental factors and microorganisms clearly.This study took the cotton field soil samples from southern,northern,and eastern Xinjiang by analyzing the cotton fields with different altitudes and soil texture in northern and southern Xinjiang,the soil physical and chemical properties,bacterial community composition,α and β diversity of cotton fields in Bale,Kuitun,Shihezi,Fukang and Hami regions of eastern Xinjiang were analyzed from west to east in the economic belt of Northern Slope of Tianshan Mountains.Establish a network model of soil bacteria co-occurrence in spring,summer,and autumn,and a random forest model.And do ecological function prediction and metabolic function prediction.On this basis,soil health classification and evaluation based on soil microbial biological integrity index were established.The main conclusions are as follows:1.Soil microbial community structure and diversity in XinjiangAccording to high-throughput sequencing was performed on 171 soil samples from the study area,the sequence of 12,530,035 high-quality bacteria was obtained,24 soil samples were selected from Kuitun,we had 4,593,695 high-quality soil fungi sequences.The bacteria diversity and the significant results were found at the gate level,Proteobacteriaa,Verrucomicrobia and Chloroflexi.Fungi diversity and major results were found at the gate level,Ascomycota,Basidiomycota,Zygomycota,Chytridiomycota.The results showed that Proteobacteria were the main bacteria,and Ascomycota were the main fungi in Xinjiang cotton field soil.In the economic belt on the Northern Slope of the Tianshan Mountains,there was a significant difference between eastern and southern Xinjiang in the dominant bacteria whose abundance was more than 1%: Proteobacteria,Bacteroidetes and Verrucomicrophyla were higher in Aksu in southern Xinjiang than in Bole,Kuitun,Shihezi,Changji and Hami in eastern Xinjiang.The Actinomycetes,Acidobacteria and Firmicutes in Aksu of southern Xinjiang were higher than those in Bole,Kuitun,Shihezi,Changji and Hami of eastern Xinjiang.The results of α diversity analysis showed that the species richness,pedigree diversity,and PD index of soil microbial species in Aksu of southern Xinjiang were higher than those in Bole,Kuitun,Shihezi,Changji,and Hami of eastern Xinjiang,indicating that the species richness in southern Xinjiang was relatively high.β diversity showed that PC1=55.42%,PC2=21.54%,and the community structure of northern,eastern,and southern Xinjiang were significantly separated,with a small portion of overlap.The bacterial community structure in the soil of the oasis cotton field and virgin Populus euphratica forest in Xinjiang was significantly different.There were no significant differences in soil fungal αand β diversity among cotton fields with different yields.The microbial community structure was more concentrated,and the bacterial community structure richness was higher in southern Xinjiang.These results provided a basis for better utilization of soil microorganisms in cotton fields and strong support for screening in-situ soil microorganisms.2.Seasonal changes had significant effects on the structure and function of soil microbial community in the cotton fieldSoil bacterial β diversity in cotton fields was affected by different seasons.The distance between spring and summer communities was close,and the distance between autumn and spring communities was significantly different.In autumn,the later the ripening of cotton fields in Xinjiang,the lower the Actinomycetes concentration.The abundance of Actinomycetes in Hami and Kuitun was 0.08-0.16,and the abundance of actinomycetes in Shihezi and Bole was 0.32-0.4.FAPROTAX predicted the ecological function of the soil bacterial community in the Xinjiang cotton field in spring,summer,and autumn.The predictable proportion was 31.45%,32.3%,and 15.3%,respectively.The nitrification was higher in northern Xinjiang than in southern Xinjiang and eastern Xinjiang,and the denitrification was higher in northern Xinjiang than in southern Xinjiang and lower than that of eastern Xinjiang.The metabolic intensity of PICRUSt2 in southern Xinjiang was higher than that of northern Xinjiang and higher than that of eastern Xinjiang.Network model and random forest model were used to confirm the influence degree of the season on soil microbial community energy of cotton field and predict the ecological function and metabolic function.Theoretical breakthroughs and more robust data and evidence were obtained,which laid a foundation for screening bacteria that promote the growth and development of cotton.3.Effects of environmental factors on microbial community structure in soilIt was found that the diversity and composition of soil bacterial community in a cotton field in Xinjiang depended more on soil chemical characteristics than on altitude or soil texture.The content of available nitrogen and available potassium had important effects on the diversity of soil bacterial communities.These findings will improve our ability to predict and manage soil microbial diversity during oasis development.4.Soil healthy evaluation system based on soil microbial integrity indexIn whole research areas,a total of 171 soil samples were selected to contribute to the M-IBI system.The M-IBI numbers were >2.17,1.71-2.17,1.14-1.71,0.57-1.14,and <0.57,respectively,which present the health,sub-health,common,poorness,and barrenness.About68% were healthy,25% were in sub-health,4% and less than 5% were in poor or barren status.5.Big-data platform and analysis process of soil microbial resources in Xinjiang cotton field based on the Hadoop＿8A random forest regression model was established to predict cotton yield and disease occurrence based on the data of dominant bacteria and α diversity,and the fitting result was more than 0.83.The platform has integrated about 1.7 GB of soil microbial data and 5-6 GB of multi-scale multi-environmental factor data so as to better grasp the soil microbial resources of Xinjiang cotton field,explore the ecological mechanism of soil microbiome driving soil health,and provide strong support for the establishment of microbial indicators in the evaluation of cotton field soil health. |
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