| Lack of arable land per capita and degradation of arable land are the stumbling blocks that hinder the development of modern agriculture in China.The area of saline land in China is about 100 million hectares,about 10% of the total global saline land area.Saline land is an important reserve arable land resource in China,with large area,wide distribution,various types,low soil quality,low crop yield and other characteristics,urgently need effective technology to improve it.Cultivation rice is one of the important ways to improve soda saline land,balancing the dual role of improving ecological environment and developing economy.Previous studies have mostly investigated the effect of rice cultivation on the improvement of saline soils in respect to the effect of different years of rice cultivation on soil physicochemical properties and enzyme activities,but lacked analysis related to soil microorganisms.Soil microorganisms are an important indicator of soil fertility and provide guidance for the improvement of saline lands.In this study,we examined the physicochemical properties of each saline soil sample by chemical methods and the microbial community diversity,community composition and distribution evolution of each saline soil sample by high-throughput sequencing technology in the same area of Baicheng City,Jilin Province,without rice cultivation and with five rice planting years from 1 to 5years.The relationship between the physicochemical properties of saline soils and bacterial and fungal communities was also quantified by redundancy analysis,with the aim of exploring the mechanisms involved in the evolution of the distribution of bacterial and fungal communities in saline soils affected by the years of rice cultivation,and providing guidance for the cultivation of rice to improve saline soils.The main findings of this study are as follows:(1)A total of 629 genera of 367 families in 147 orders of 54 phyla of bacteria and 331 genera in 213 families in 110 orders of 41 phyla of 14 fungi were found in uncultivated rice soils and different years of rice cultivation soil(1 year,2 years,3years,4 years and 5 years).The years of rice cultivation significantly affected the abundance and diversity of bacteria and fungi in saline soils.(2)The dominant bacterial phyla in the saline soil after the cultivated rice were Proteobacteria(14.30%-43.20%),Chloroflexi(12.29%-26.15%),Acidobacteria(7.19%-21.17%),Actinobacteria(3.40%-16.57%)and Gemmatimonadetes(2.46%-9.67%).The relative abundance of Proteobacteria first increased significantly and then remained stable;the relative abundance of Chloroflexi first decreased significantly and then increased;the relative abundance of Acidobacteria,Actinobacteria and Gemmatimonadetes gradually decreased with the number of years of rice cultivation.The dominant bacterial genera were Thiobacillus(0.11%-12.90%),Gillisia(0.01%-4.43%),Anaerolinea(0.59%-3.74%),Sulfuricurvum(0.0%-3.7%),and Aqueous(0.08%-2.6%).The relative abundance of all the above dominant genera increased with increasing years of rice cultivation.(3)The dominant fungal phyla in saline soils after the cultivated rice were Ascomycota(22.08%-72.89%),Mortierellomycota(0.81%-44.58%),Basidiomycota(1.40%-19.01%),Rozellomycota(0.18%-15.01%),Chytridiomycota(0.45%-7.62%)and Glomeromycota(0.57%-5.46%).The dominant genera were Mortierella(0.81%-44.57%),Chrysosporium(0.52%-44.07%),Fusarium(0.42%-6.42%)and Scutellinia(0.06%-2.90%),respectively.The relative abundance of Mortierella increased except for a decrease in the 4th year;the relative abundance of Chrysosporium increased sharply from 0.52% to 44.07% in the 2nd year;the relative abundance of Scutellinia increased after rice planting and then decreased.(4)In this study,soil physical and chemical properties are the main factors affecting the change of bacterial community structure,and p H is the key factor affecting the change of bacterial community structure in saline-alkali soil.The community structure of fungi is affected by many factors,and TOC is the key factor. |
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