| Waste of resources and environment problem resulted from a large amount of coal gangue in the process of coal mining have become one of the global environmental problems.Study on reclamation and ecological restoration of coal gangue accumulation areas at home and abroad mainly focuses on geomorphic remodeling,soil improvement and reconstruction,vegetation restoration,etc.Even from the perspective of soil hydrology,ecological restoration of mining areas is limited to the general comparison of soil property indexes.How to identify the original ecosystem structure and the mechanism of soil hydrological damage,and to explore the theory,direction and path of reclamation and ecological restoration in coal gangue accumulation areas have become the frontiers of international ecological hydrology and restoration ecology research.In addition,effects of soil reconstruction and ecological restoration under different vegetations on soil microbial community structure and interaction between vegetation and microbial community are getting more and more atttention,which has become one of the hot topics in ecological restoration.In this paper,based on the data from field experiment,through the study of soil physical and chemical properties,microbial diversity,and ionomic and metabolomic laws under different ecological reconstruction modes in gangue accumulation areas,we try to propose and interprete following question: the evolution law of soil hydrological properties under different ecological reconstruction modes,and the mechanism and driving factors of soil hydrological properties optimization under different ecological reconstruction modes.The main results are as follows:(1)Both soil compound ratio and grain size of coal gangue in newly constructed soil have effects on plant biomass.The plant height growth indexes of different reconstruction models satisfied Gaussian model.C1G3 treatment(coal gangue soil ratio of 1:9 W/W,coal gangue grain size of 5 ? 8mm)had the highest comprehensive evaluation value of 27.88 points.C3G3treatment(coal gangue soil compound ratio 5:5 W/W,coal gangue particle size 5-8 mm)had the lowest comprehensive evaluation value of 21.78 points.(2)Soil enzyme activity increased significantly among the different plant mulching patterns.The activity of acid phosphatase increased significantly with different plant mulching at different depths.The activity of sucrase in shallow soil was significantly higher than that in the control group with different plant cover types.For example,the herb area increased by63.5% in the middle layer,while the shrub area,poplar area and poplar tabulae pine mixed area increased by 77.5%,58.3%,and 67.9% in the shallow layer,respectively.The increase intensity of sucrase activity in shallow soil among different plants was also different,which was as follows: herb plot(2.68)> poplar(2.41)> shrub(2.12)> Pinus tabulaeformis(0.73)?Pinus tabulaeformis(0.72).Plant cover is an important factor affecting the distribution of soil elements.The element similarity of herb and shrub areas was high,and the element similarity of mixed area of pinus tabulaeformis,poplar and pinus tabulaeformis was high.The herb area and shrub area have more B,Na,Ba,K,V,Sr,Mo,U,Rb,Cr,Mn,As,Fe,Co,Cs,Cu,Ni,and Pb,while Mg,P,and Ca are relatively few;at the same time,the contents of S,Zn,Cd,Bi,and I elements in the deep soil of the mixed-planting area of poplar and tabulaeformis are higher than those of other elements.group was 2.12?4.52(log2FC)times more.The content of soil available elements in arbor area(mixed species of Pinus tabulaeformis,poplar and pinus tabulaeformis)was less than that in control area,herb area and shrub area,and the distribution characteristics of soil available elements were similar to that in total soil elements.Refactoring soil after vegetation restoration can effectively improve soil physical and chemical properties,soil element distribution and the total effective state,the soil enzyme activity and soil microbial community diversity,vegetation restoration to promote mining area's fragile ecological environment play an important role,as a result,the vegetation coverage is coal gangue accumulation zone soil hydrological properties optimization the first drive element.(3)There are significant differences in microbial abundance between different plant types and different depths of soil.The microbial abundance in the shallow and middle soils in the plant coverage area is significantly higher than that in the control area,and the microbial abundance in the deep soil varies with plant types,such as shrub areas and poplar areas.,poplar and tabulaeformis mixed area increased by 8.62%,11.06%,32.05%,respectively,while the herb area,tabular pine area decreased by 13.20% and 15.90%.There were significant differences in the proportion of Proteobacteria and Firmicutes at phylum level in soil with different depths of plant covered areas.Bacteroidetes and Firmicutes replaced Proteobacteria and Actinobacteria in the deep layer of poplar and Pinus tabulaeformis mixed area compared with other treatments.Thiobacillus was found to be abundant in the middle and deep soil of shrub areas.There were 81,107 and 120 different microbial strains in shallow,middle and deep vertical depths,respectively.There were 22 key node microorganisms(degree>10)in soil bacteria under different ecological reconstruction modes.The types of soil microbial interactions were different in each reconstruction mode and at different depths.(4)A total of 4995 positive ion pattern metabolites and 1371 negative ion pattern metabolites were identified in soil metabolites of different reconstruction patterns.Lipids and lipid molecules,organic oxygen compounds,organic acids and their derivatives,phenylpropanes and polyketides,lignans,neolignans and related compounds,and organic nitrogen compounds were the main metabolite classes.All types of plots showed that there were more differential metabolites in the shallow layer(168-258),and the number of differential metabolites in the middle and deep layers was roughly similar.Among the differential metabolites among the comparison groups,all of them were mainly up-regulated,superficial(Up:105?168,Down:57?168),middle(Up:65?78,Down:35?74),deep(Up:105?168,Down:57?168)Up: 58?107,Down: 20?42).5'-Butyrylphosphouridine,Sucrose,3-Oxo-3-ureidopropanoate in the shallow soil of the plant coverage area were all similar to those in the control group in the shallow soil.Significant changes compared to the.In addition,Isopalmitic acid,L-Valine,L-Histidinol,Methenamine,4-Ethylphenol,and 4-Ethylphenol were all significant differences among multiple comparison groups.(5)There are 22 key node microorganisms(degree>10)in soil bacteria under different ecological reconstruction modes.The interaction relationship between environmental factors and microorganisms in different ecological reconstruction models showed the law of shallow layer>deep layer>middle layer.There are also some differences in the environmental factors that play a major role in microbes in different reconstruction modes and depths of soil.Random forest analysis screened out the key environmental factors affecting the Shannon index of the microbial community,and the top six were Na,Cs,pH,Rb,Zn,and Cd.The interaction between soil microorganisms and metabolites in different ecological reconstruction models showed that the metabolites in the control area mainly had a more complex microbial metabolism network in the shallow layer,and the interaction relationship between the plant cover area in the middle and deep layers was stronger.And different types of soil microbial interactions at different depths.The interaction relationship between environmental factors and microorganisms in different ecological reconstruction models is as follows: shallow layer >deep layer > middle layer.Vegetation cover significantly increased soil microbial diversity and enhanced the abundance of soil microorganisms at different depths.The regulation of soil moisture by root exudates,plant litter,and cover vegetation of different plants significantly changed the distribution structure of soil microorganisms,enriched metabolic pathways and metabolite species,and accelerated the process of soil remediation in coal gangue mining areas. |
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