Biochar application is known to improve soil quality,enhance nutrient bioavailability,and increase carbon retention.However,its effects on ecoenzymatic activities and stoichiometric relationships in saline-alkali soil...Biochar application is known to improve soil quality,enhance nutrient bioavailability,and increase carbon retention.However,its effects on ecoenzymatic activities and stoichiometric relationships in saline-alkali soils remain poorly understood.This study examines how biochar amendments influence microbial stoichiometry,nutrient limitations,and carbon use efficiency in saline-alkali soils.We compared two types of biochar-acid-modified biochar(pH 2.3)and alkaline biochar(pH 8.8)-at application rates of 1%,2%,and 5%in soils planted with Medicago sativa L.Our results demonstrated that alkaline biochar increased enzymatic C:N stoichiometry at higher rates,while acid-modified biochar decreased it at lower rates.Both biochar types reduced enzymatic C:P and N:P stoichiometry;alkaline biochar shifted microbial metabolism from nitrogen to phosphorus limitation,while acid-modified biochar alleviated nitrogen limitation at rates of 2%and 5%.Furthermore,alkaline biochar at rates of 2%and 5%reduced microbial carbon limitation and enhanced carbon use efficiency,whereas acid-modified biochar did not.Microbial carbon use efficiency was consistently higher with alkaline biochar than with acid-modified biochar at equivalent application rates.These findings highlight that the impact of biochar on soil microbial processes depends on the biochar feedstock type,with differences in surface adsorption properties,nutrient supply,pH,and liming effects driving changes in soil properties,microbial community dynamics,and plant growth.Our study offers insights into optimizing nutrient cycling and carbon sequestration in saline-alkali soils,demonstrating the potential of biochar in sustainable soil management.展开更多
Soil functional microbial taxa and extracellular enzymes are involved in a variety of biogeochemical cycling processes.Although many studies have revealed the vertical change patterns of microbial communities along so...Soil functional microbial taxa and extracellular enzymes are involved in a variety of biogeochemical cycling processes.Although many studies have revealed the vertical change patterns of microbial communities along soil profile,the general understanding of the coupling changes in the functional gene abundances(FGAs)and extracellular enzyme activities(EEAs)in soil profiles is still limited,which hinders us from revealing soil ecosystem processes.Herein,we comparatively investigated the FGAs and EEAs in the diagnostic A,B,and C horizons of soil profiles obtained from two suborders of Isohumosols(Mollisols),Ustic and Udic Isohumosols,in Northeast China based on quantitative real-time polymerase chain reaction and standard fluorometric techniques,respectively.The distribution patterns of both FGAs and EEAs significantly distinguished by the two soil suborders and were also separated from A to C horizon.Additionally,the variations of EEAs and FGAs were greater in Udic Isohumosols compared to Ustic Isohumosols along soil profiles,and greater changes were observed in C horizon than in A horizon.Both FGAs and EEAs correspondently decreased along the soil profiles.However,when normalized by soil organic carbon,the specific EEAs significantly increased in deep soil horizons,suggesting that microorganisms will input more resources to the production of enzymes to ensure microbial nutrient requirements under resource scarcity.More importantly,we revealed that soil microbial nutrient demands were limited by carbon(C)and phosphorus(P),and the C and P limitations significantly increased along soil profiles with a greater C limitation observed in Ustic Isohumosols than in Udic Isohumosols.Overall,our findings provided solid evidence showing the links between FGAs,EEAs,and microbial nutrient limitations,which would be helpful for a better understanding of the ecosystem processes in soil profiles.展开更多
Microbes play an important role in the carbon cycle and nutrient flow of the soil ecosystem.However,the response of microbial activities to long-term warming over decades is poorly understood.To determine how warming ...Microbes play an important role in the carbon cycle and nutrient flow of the soil ecosystem.However,the response of microbial activities to long-term warming over decades is poorly understood.To determine how warming changes ecoenzyme activity and microbial nutrient limitation,we conducted a long-term,21 years,experiment,on the Qinghai–Tibet Plateau.We selected typical grass-and shrub-covered plots,used fiberglass open-top chambers(OTCs)to raise the temperature,conducted soil sampling at different depths,studied the response of nutrient-acquiring enzyme activity and stoichiometry,and conducted vector analysis of stoichiometry.Our results showed that long-term warming did not have a notable effect on the activity of nutrient-acquiring enzymes or enzymatic stoichiometry.However,Spearman correlation analysis indicated a significant and positive correlation between ecoenzyme activity and the available nutrients and microbial biomass in soil.Vector analysis of stoichiometry showed phosphorus limitation for all soil microbes at different depths,regardless of whether the soil experienced warming.These changes in enzymatic stoichiometry and vector analysis suggested that microbial nutrient limitation was not alleviated substantially by long-term warming,and warming did not considerably affect the stratification of microbial nutrient limitation.Our research has also shown that long-term warming does not significantly change soil ecoenzyme activity and original microbial nutrient limitation at different soil depths within the OTUsʼimpact range.These results could help improve understanding of microbial thermal acclimation and response to future long-term global warming.展开更多
基金by the National Natural Science Foundation of China(42101057&32171580)Science and Technology Plan of Gansu Province(24JRRA412)+1 种基金Fundamental Research Funds for the Central Universities of China(lzujbky-2021-ey03)the Open Project of State Key Laboratory of Plateau Ecology and Agriculture,Qinghai University(2024-KF-04).
文摘Biochar application is known to improve soil quality,enhance nutrient bioavailability,and increase carbon retention.However,its effects on ecoenzymatic activities and stoichiometric relationships in saline-alkali soils remain poorly understood.This study examines how biochar amendments influence microbial stoichiometry,nutrient limitations,and carbon use efficiency in saline-alkali soils.We compared two types of biochar-acid-modified biochar(pH 2.3)and alkaline biochar(pH 8.8)-at application rates of 1%,2%,and 5%in soils planted with Medicago sativa L.Our results demonstrated that alkaline biochar increased enzymatic C:N stoichiometry at higher rates,while acid-modified biochar decreased it at lower rates.Both biochar types reduced enzymatic C:P and N:P stoichiometry;alkaline biochar shifted microbial metabolism from nitrogen to phosphorus limitation,while acid-modified biochar alleviated nitrogen limitation at rates of 2%and 5%.Furthermore,alkaline biochar at rates of 2%and 5%reduced microbial carbon limitation and enhanced carbon use efficiency,whereas acid-modified biochar did not.Microbial carbon use efficiency was consistently higher with alkaline biochar than with acid-modified biochar at equivalent application rates.These findings highlight that the impact of biochar on soil microbial processes depends on the biochar feedstock type,with differences in surface adsorption properties,nutrient supply,pH,and liming effects driving changes in soil properties,microbial community dynamics,and plant growth.Our study offers insights into optimizing nutrient cycling and carbon sequestration in saline-alkali soils,demonstrating the potential of biochar in sustainable soil management.
基金supported by the National Natural Science Foundation of China(No.41977202)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA28020201)the Provincial Natural Science Foundation of Heilongjiang,China(No.ZD2022D001)。
文摘Soil functional microbial taxa and extracellular enzymes are involved in a variety of biogeochemical cycling processes.Although many studies have revealed the vertical change patterns of microbial communities along soil profile,the general understanding of the coupling changes in the functional gene abundances(FGAs)and extracellular enzyme activities(EEAs)in soil profiles is still limited,which hinders us from revealing soil ecosystem processes.Herein,we comparatively investigated the FGAs and EEAs in the diagnostic A,B,and C horizons of soil profiles obtained from two suborders of Isohumosols(Mollisols),Ustic and Udic Isohumosols,in Northeast China based on quantitative real-time polymerase chain reaction and standard fluorometric techniques,respectively.The distribution patterns of both FGAs and EEAs significantly distinguished by the two soil suborders and were also separated from A to C horizon.Additionally,the variations of EEAs and FGAs were greater in Udic Isohumosols compared to Ustic Isohumosols along soil profiles,and greater changes were observed in C horizon than in A horizon.Both FGAs and EEAs correspondently decreased along the soil profiles.However,when normalized by soil organic carbon,the specific EEAs significantly increased in deep soil horizons,suggesting that microorganisms will input more resources to the production of enzymes to ensure microbial nutrient requirements under resource scarcity.More importantly,we revealed that soil microbial nutrient demands were limited by carbon(C)and phosphorus(P),and the C and P limitations significantly increased along soil profiles with a greater C limitation observed in Ustic Isohumosols than in Udic Isohumosols.Overall,our findings provided solid evidence showing the links between FGAs,EEAs,and microbial nutrient limitations,which would be helpful for a better understanding of the ecosystem processes in soil profiles.
基金supported financially by the National Natural Science Foundation of China(31672475)Qinghai Provincial Key Laboratory of Restoration Ecology in Cold Regions,North-west Institute of Plateau Biology(2020-KF-04)Qinghai Innovation Platform Construction Project(2021-ZJ-Y010).
文摘Microbes play an important role in the carbon cycle and nutrient flow of the soil ecosystem.However,the response of microbial activities to long-term warming over decades is poorly understood.To determine how warming changes ecoenzyme activity and microbial nutrient limitation,we conducted a long-term,21 years,experiment,on the Qinghai–Tibet Plateau.We selected typical grass-and shrub-covered plots,used fiberglass open-top chambers(OTCs)to raise the temperature,conducted soil sampling at different depths,studied the response of nutrient-acquiring enzyme activity and stoichiometry,and conducted vector analysis of stoichiometry.Our results showed that long-term warming did not have a notable effect on the activity of nutrient-acquiring enzymes or enzymatic stoichiometry.However,Spearman correlation analysis indicated a significant and positive correlation between ecoenzyme activity and the available nutrients and microbial biomass in soil.Vector analysis of stoichiometry showed phosphorus limitation for all soil microbes at different depths,regardless of whether the soil experienced warming.These changes in enzymatic stoichiometry and vector analysis suggested that microbial nutrient limitation was not alleviated substantially by long-term warming,and warming did not considerably affect the stratification of microbial nutrient limitation.Our research has also shown that long-term warming does not significantly change soil ecoenzyme activity and original microbial nutrient limitation at different soil depths within the OTUsʼimpact range.These results could help improve understanding of microbial thermal acclimation and response to future long-term global warming.
