The self-weight of solid waste or machine-rolled compaction can induce or trigger contaminant migration in the landfill.Although the consolidation-induced hydraulic gradient driving solution transport has been extensi...The self-weight of solid waste or machine-rolled compaction can induce or trigger contaminant migration in the landfill.Although the consolidation-induced hydraulic gradient driving solution transport has been extensively investigated,little attention has been paid to ion migration caused by its concentration gradient variation.It is necessary to more precisely predict the multi-stage contaminant transports in deforming porous material.Based on the modified Cam-clay model,the proposed fluid-solid coupled model can simulate the elastoplastic deformation behavior of layered kaolinite and KBr solution transport/sorption,and its modeling results were validated by published laboratory data.The solid-fluid interactions were analyzed by comparing various transport manners of K^(+)and Br^(−)from excess pore pressure generation to dissipation.Results reveal that the consolidation process can accelerate KBr solute advection from the contaminated layer into the uncontaminated layer,and then affects the subsequent diffusion,mechanical dispersion and sorption for K^(+)and Br^(−).The simulations also indicate that consolidation-induced solute transport is time-dependent,and therefore the ion diffusion and mechanical dispersion should receive more attention.展开更多
Partitioning of soil organic matter for particulate organic carbon(POC)and mineral-associated organic carbon(MAOC)is essential to understand carbon(C)storage under climate change,given their distinct properties and re...Partitioning of soil organic matter for particulate organic carbon(POC)and mineral-associated organic carbon(MAOC)is essential to understand carbon(C)storage under climate change,given their distinct properties and response to warming.The mechanisms underlying warming-induced changes in C pools in black soils(Mollisols)remain unknown,owing to the stability of C pools and the complexity of their associated microbial communities.This study elucidates POC and MAOC contents and their microbial controls in black soils along a mean annual temperature(MAT)gradient from 0.6 to 7.3℃.The POC content(3.3-17 g kg^(−1))increased with MAT,while MAOC content(33-60 g kg^(−1))decreased,indicating accelerated C turnover with warming.Higher MAT shifted the bacterial communities from K-to r-strategies,aligning with increased POC content.The dominance of r-strategists facilitated rapid utilization and mineralization of organic compounds(e.g.,mainly with low C/N ratio),reducing MAOC and increasing POC through sustained plant residue inputs.This shift towards r-strategists also corresponded with increased abundance of saprotrophic fungi and stronger bacteria-saprotrophic fungi associations.Warming in colder regions may release available organic matter that saprotrophic fungi preferentially utilize over plant residues to minimize energy expenditure,decreasing POC decomposition.Our findings suggest that integrating microbial r-/K-strategies help to elucidate these mechanisms and simplify the interpretation of temperature effects on the dynamics of two main functional pools of soil organic matter.展开更多
Fertilizers are widely used to produce more food, inevitably altering the diversity and composition of soil organisms. The role of soil biodiversity in controlling multiple ecosystem services remains unclear, especial...Fertilizers are widely used to produce more food, inevitably altering the diversity and composition of soil organisms. The role of soil biodiversity in controlling multiple ecosystem services remains unclear, especially after decades of fertilization. Here, we assess the contribution of the soil functionalities of carbon(C), nitrogen(N), and phosphorus(P) cycling to crop production and explore how soil organisms control these functionalities in a 33-year field fertilization experiment. The long-term application of green manure or cow manure produced wheat yields equivalent to those obtained with chemical N, with the former providing higher soil functions and allowing the functionality of N cycling(especially soil N mineralization and biological N fixation) to control wheat production. The keystone phylotypes within the global network rather than the overall microbial community dominated the soil multifunctionality and functionality of C,N, and P cycling across the soil profile(0–100 cm). We further confirmed that these keystone phylotypes consisted of many metabolic pathways of nutrient cycling and essential microbes involved in organic C mineralization, N_(2)O release, and biological N fixation. The chemical N, green manure, and cow manure resulted in the highest abundances of amoB, nifH, and GH48 genes and Nitrosomonadaceae,Azospirillaceae, and Sphingomonadaceae within the keystone phylotypes, and these microbes were significantly and positively correlated with N_(2)O release, N fixation, and organic C mineralization, respectively. Moreover, our results demonstrated that organic fertilization increased the effects of the network size and keystone phylotypes on the subsoil functions by facilitating the migration of soil microorganisms across the soil profiles and green manure with the highest migration rates. This study highlights the importance of the functionality of N cycling in controlling crop production and keystone phylotypes in regulating soil functions, and provides selectable fertilization strategies for maintaining crop production and soil functions across soil profiles in agricultural ecosystems.展开更多
基金The financial support of the National Natural Science Foundation of China (Grant No. 41772154)Natural Science Foundation of Shandong Province (ZR2019MA009)Science and Technology Project of Qingdao West Coast New Area (2019-47)
文摘The self-weight of solid waste or machine-rolled compaction can induce or trigger contaminant migration in the landfill.Although the consolidation-induced hydraulic gradient driving solution transport has been extensively investigated,little attention has been paid to ion migration caused by its concentration gradient variation.It is necessary to more precisely predict the multi-stage contaminant transports in deforming porous material.Based on the modified Cam-clay model,the proposed fluid-solid coupled model can simulate the elastoplastic deformation behavior of layered kaolinite and KBr solution transport/sorption,and its modeling results were validated by published laboratory data.The solid-fluid interactions were analyzed by comparing various transport manners of K^(+)and Br^(−)from excess pore pressure generation to dissipation.Results reveal that the consolidation process can accelerate KBr solute advection from the contaminated layer into the uncontaminated layer,and then affects the subsequent diffusion,mechanical dispersion and sorption for K^(+)and Br^(−).The simulations also indicate that consolidation-induced solute transport is time-dependent,and therefore the ion diffusion and mechanical dispersion should receive more attention.
基金supported by the National Key Research and Development Program of China[Grant No.2022YFD1500202]Strategic Priority Research Program of the Chinese Academy of Sciences[Grant No.XDA28020202]+1 种基金China Postdoctoral Science Foundation[Grant No.2024M753332]the RUDN University Strategic Academic Leadership Program.
文摘Partitioning of soil organic matter for particulate organic carbon(POC)and mineral-associated organic carbon(MAOC)is essential to understand carbon(C)storage under climate change,given their distinct properties and response to warming.The mechanisms underlying warming-induced changes in C pools in black soils(Mollisols)remain unknown,owing to the stability of C pools and the complexity of their associated microbial communities.This study elucidates POC and MAOC contents and their microbial controls in black soils along a mean annual temperature(MAT)gradient from 0.6 to 7.3℃.The POC content(3.3-17 g kg^(−1))increased with MAT,while MAOC content(33-60 g kg^(−1))decreased,indicating accelerated C turnover with warming.Higher MAT shifted the bacterial communities from K-to r-strategies,aligning with increased POC content.The dominance of r-strategists facilitated rapid utilization and mineralization of organic compounds(e.g.,mainly with low C/N ratio),reducing MAOC and increasing POC through sustained plant residue inputs.This shift towards r-strategists also corresponded with increased abundance of saprotrophic fungi and stronger bacteria-saprotrophic fungi associations.Warming in colder regions may release available organic matter that saprotrophic fungi preferentially utilize over plant residues to minimize energy expenditure,decreasing POC decomposition.Our findings suggest that integrating microbial r-/K-strategies help to elucidate these mechanisms and simplify the interpretation of temperature effects on the dynamics of two main functional pools of soil organic matter.
基金supported by the National Key Research and Development Program of China(2021YFD1700200)the earmarked fund for CARS-Green manure(CARS-22)the Agricultural Science and Technology Innovation Program of CAAS。
文摘Fertilizers are widely used to produce more food, inevitably altering the diversity and composition of soil organisms. The role of soil biodiversity in controlling multiple ecosystem services remains unclear, especially after decades of fertilization. Here, we assess the contribution of the soil functionalities of carbon(C), nitrogen(N), and phosphorus(P) cycling to crop production and explore how soil organisms control these functionalities in a 33-year field fertilization experiment. The long-term application of green manure or cow manure produced wheat yields equivalent to those obtained with chemical N, with the former providing higher soil functions and allowing the functionality of N cycling(especially soil N mineralization and biological N fixation) to control wheat production. The keystone phylotypes within the global network rather than the overall microbial community dominated the soil multifunctionality and functionality of C,N, and P cycling across the soil profile(0–100 cm). We further confirmed that these keystone phylotypes consisted of many metabolic pathways of nutrient cycling and essential microbes involved in organic C mineralization, N_(2)O release, and biological N fixation. The chemical N, green manure, and cow manure resulted in the highest abundances of amoB, nifH, and GH48 genes and Nitrosomonadaceae,Azospirillaceae, and Sphingomonadaceae within the keystone phylotypes, and these microbes were significantly and positively correlated with N_(2)O release, N fixation, and organic C mineralization, respectively. Moreover, our results demonstrated that organic fertilization increased the effects of the network size and keystone phylotypes on the subsoil functions by facilitating the migration of soil microorganisms across the soil profiles and green manure with the highest migration rates. This study highlights the importance of the functionality of N cycling in controlling crop production and keystone phylotypes in regulating soil functions, and provides selectable fertilization strategies for maintaining crop production and soil functions across soil profiles in agricultural ecosystems.
