Water-saving irrigation strategies can successfully alleviate methane emissions from rice fields,but significantly stimulate nitrous oxide(N_(2)O)emissions because of variations in soil oxygen level and redox potentia...Water-saving irrigation strategies can successfully alleviate methane emissions from rice fields,but significantly stimulate nitrous oxide(N_(2)O)emissions because of variations in soil oxygen level and redox potential.However,the relationship linking soil N_(2)O emissions to nitrogen functional genes during various fertilization treatments in water-saving paddy fields has rarely been investigated.Furthermore,the mitigation potential of organic fertilizer substitution on N_(2)O emissions and the microbial mechanism in rice fields must be further elucidated.Our study examined how soil N_(2)O emissions were affected by related functional microorganisms(ammonia-oxidizing archaea(AOA),ammonia-oxidizing bacteria(AOB),nirS,nirK and nosZ)to various fertilization treatments in a rice field in southeast China over two years.In this study,three fertilization regimes were applied to rice cultivation:a no nitrogen(N)(Control),an inorganic N(Ni),and an inorganic N with partial N substitution with organic manure(N_(i)+N_(o)).Over two rice-growing seasons,cumulative N_(2)O emissions averaged 0.47,4.62 and 4.08 kg ha^(−1)for the Control,Ni and N_(i)+N_(o)treatments,respectively.In comparison to the Ni treatment,the N_(i)+N_(o)fertilization regime considerably reduced soil N_(2)O emissions by 11.6%while maintaining rice yield,with a lower N_(2)O emission factor(EF)from fertilizer N of 0.95%.Nitrogen fertilization considerably raised the AOB,nirS,nirK and nosZ gene abundances,in comparison to the Control treatment.Moreover,the substitution of organic manure for inorganic N fertilizer significantly decreased AOB and nirS gene abundances and increased nosZ gene abundance.The AOB responded to N fertilization more sensitively than the AOA.Total N_(2)O emissions significantly correlated positively with AOB and nirS gene abundances while having a negative correlation with nosZ gene abundance and the nosZ/nirS ratio across N-fertilized plots.In summary,we conclude that organic manure substitution for inorganic N fertilizer decreased soil N_(2)O emissions primarily by changing the soil NO_(3)^(−)-N,pH and DOC levels,thus inhibiting the activities of ammonia oxidation in nitrification and nitrite reduction in denitrification,and strengthening N_(2)O reduction in denitrification from water-saving rice paddies.展开更多
The terrestrial carbon(C) cycle plays an important role in global climate change, but the vegetation and environmental drivers of C fluxes are poorly understood. We established a global dataset with 1194 available dat...The terrestrial carbon(C) cycle plays an important role in global climate change, but the vegetation and environmental drivers of C fluxes are poorly understood. We established a global dataset with 1194 available data across site-years including gross primary productivity(GPP), ecosystem respiration(ER), net ecosystem productivity(NEP), and relevant environmental factors to investigate the variability in GPP, ER and NEP, as well as their covariability with climate and vegetation drivers.The results indicated that both GPP and ER increased exponentially with the increase in mean annual temperature(MAT)for all biomes. Besides MAT, annual precipitation(AP) had a strong correlation with GPP(or ER) for non-wetland biomes.Maximum leaf area index(LAI) was an important factor determining C fluxes for all biomes. The variations in both GPP and ER were also associated with variations in vegetation characteristics. The model including MAT, AP and LAI explained 53%of the annual GPP variations and 48% of the annual ER variations across all biomes. The model based on MAT and LAI explained 91% of the annual GPP variations and 92.9% of the annual ER variations for the wetland sites. The effects of LAI on GPP, ER or NEP highlighted that canopy-level measurement is critical for accurately estimating ecosystem–atmosphere exchange of carbon dioxide. The present study suggests a significance of the combined effects of climate and vegetation(e.g.,LAI) drivers on C fluxes and shows that climate and LAI might influence C flux components differently in different climate regions.展开更多
Elevated levels of atmospheric CO_(2)(eCO_(2))promote rice growth and increase methane(CH_(4))emissions from rice paddies,because increased input of plant photosynthate to soil stimulates methanogenic archae.However,t...Elevated levels of atmospheric CO_(2)(eCO_(2))promote rice growth and increase methane(CH_(4))emissions from rice paddies,because increased input of plant photosynthate to soil stimulates methanogenic archae.However,temporal trends in the effects of eCO_(2)on rice growth and CH_(4)emissions are still unclear.To investigate changes in the effects of eCO_(2)over time,we conducted a two-season pot experiment in a walk-in growth chamber.Positive effects of eCO_(2)on rice leaf photosynthetic rate,biomass,and grain yield were similar between growing seasons.However,the effects of eCO_(2)on CH_(4) emissions decreased over time.Elevated CO_(2)increased CH_(4)emissions by 48%-101%in the first growing season,but only by 28%-30%in the second growing season.We also identified the microbial process underlying the acclimation of CH4 emissions to atmospheric CO_(2)enrichment:eCO_(2)stimulated the abundance of methanotrophs more strongly in soils that had been previously exposed to eCO_(2)than in soils that had not been.These results emphasize the need for long-term eCO_(2)experiments for accurate predictions of terrestrial feedbacks.展开更多
Bio-organic fertilizers enriched with plant growth-promoting microbes(PGPMs)have been widely used in crop fields to promote plant growth and maintain soil microbiome functions.However,their potential effects on N_(2)O...Bio-organic fertilizers enriched with plant growth-promoting microbes(PGPMs)have been widely used in crop fields to promote plant growth and maintain soil microbiome functions.However,their potential effects on N_(2)O emissions are of increasing concern.In this study,an in situ measurement experiment was conducted to investigate the effect of organic fertilizer containing Trichoderma guizhouense(a plant growth-promoting fungus)on soil N_(2)O emissions from a greenhouse vegetable field.The following four treatments were used:no fertilizer(control),chemical fertilizer(NPK),organic fertilizer derived from cattle manure(O),and organic fertilizer containing T.guizhouense(O+T,referring to bio-organic fertilizer).The abundances of soil N cycling-related functional genes(amoA)from ammonium-oxidizing bacteria(AOB)and archaea(AOA),as well as nirS,nirK,and nosZ,were simultaneously determined using quantitative PCR(qPCR).Compared to the NPK plot,seasonal total N_(2)O emissions decreased by 11.7%and 18.7%in the O and O+T plots,respectively,which was attributed to lower NH_(4)^(+)-N content and AOB amoA abundance in the O and O+T plots.The nosZ abundance was significantly greater in the O+T plot,whilst the AOB amoA abundance was significantly lower in the O+T plot than in the O plot.Relative to the organic fertilizer,bio-organic fertilizer application tended to decrease N_(2)O emissions by 7.9%and enhanced vegetable yield,resulting in a significant decrease in yield-scaled N_(2)O emissions.Overall,the results of this study suggested that,compared to organic and chemical fertilizers,bio-organic fertilizers containing PGPMs could benefit crop yield and mitigate N_(2)O emissions in vegetable fields.展开更多
Aims Abiotic stresses may interact with each other to determine impacts on plants so that their combined impact is less than or more than additive.Increasing UV-B radiation and surface ozone(O3)are two major component...Aims Abiotic stresses may interact with each other to determine impacts on plants so that their combined impact is less than or more than additive.Increasing UV-B radiation and surface ozone(O3)are two major components of global change that may have such interactive impacts.Moreover,invasive and native populations of plants may respond differently to stresses as they can vary in primary and secondary metabolism.Methods Here,we conducted a factorial field experiment with open-top chambers assigned to an ozone treatment(ambient,100 ppb,or 150 ppb)and UV-B treatment(ambient or increased 20%).We grew seedlings of native and invasive populations of Triadica sebifera in these chambers for one growing season.Important Findings Invasive plants grew faster than native plants in ambient UV-B but they did not differ significantly in elevated UV-B.Litter production of invasive plants was especially sensitive to UV-B in a way that increased with UV-B for native plants but decreased for invasive plants which may be important for nutrient cycling.In ambient UV-B,total mass decreased as ozone increased.Total mass was lower with elevated UV-B but there was no additional impact of increasing ozone.Leaf area did not decrease with UV-B so SLA and LAR were lowest at ambient ozone levels.These results suggest that the effects of ozone will depend on UV-B conditions perhaps due to changes in foliar traits.The traits that allow invasive populations of plants to be successful invaders may make them especially sensitive to UV-B which may reduce their success in future climatic conditions.展开更多
Biochar has gained significant attention in agricultural and environmental research over the last two decades.This comprehensive review evaluates the effects of biochar on soil organic carbon(SOC),emission of non-CO_(...Biochar has gained significant attention in agricultural and environmental research over the last two decades.This comprehensive review evaluates the effects of biochar on soil organic carbon(SOC),emission of non-CO_(2) greenhouse gases,and crop yield,including related mechanisms and major influencing factors.The impacts of biochar on SOC,methane and nitrous oxide emissions,and crop yield are controlled by biochar and soil properties and management practices.High-temperature biochar produced from lignin-rich feedstocks may decrease methane and nitrous oxide emissions in acidic soils and strengthen long-term carbon sequestration due to its stable aromatic structure.In contrast,low-temperature biochar from manure may increase crop yield in low-fertility soils.Applying biochar to farmlands in China can increase SOC content by 1.9 Pg C and reduce methane and nitrous oxide emissions by 25 and 20 Mt CO_(2)-eq year^(−1),respectively,while increasing crop yields by 19%.Despite the increasing evidence of the positive effects of biochar,future research needs to explore the potential factors that could weaken or hinder its capacity to address climate change and secure crop production.We conclude that biochar is not a universal solution for global cropland;however,targeted applications in fields,landscapes,or regional scales,especially in low fertility and sandy soils,could realize the benefits of biochar as a climate-smart measure.展开更多
Applying biochar amendment and manure in tea plantation ecosystems can diminish soil acidification and degradation.However,the impact of these practices on soil respiration and associated mechanisms remains unclear.In...Applying biochar amendment and manure in tea plantation ecosystems can diminish soil acidification and degradation.However,the impact of these practices on soil respiration and associated mechanisms remains unclear.In this study,we combined a two-year field experiment and laboratory analyses based on soil properties,functional genes,and microbial co-occurrence networks to explore the determinants of soil respiration intensity in a subtropical tea plantation with biochar amendment and manure application.The results showed that the effect of biochar amendment on soil respiration was unconspicuous.Although biochar amendment increased bacterial richness and Shannon index,biochar amendment did not alter the abundance of species associated with C-cycling functional genes.Besides directly adding recalcitrant C to the soil,biochar also indirectly enhanced C sequestration by weakly increasing soil carbon dioxide(CO_(2))emissions.However,replacing mineral fertilizer with manure significantly stimulated soil respiration in the tea plantation,resulting in a 36%increase in CO_(2) emissions over two years.The increase in CO_(2) emissions under the manure treatment was mainly attributed to the increased soil labile C pool,the activity of hydrolytic enzymes(e.g.,cellobiohydrolase and acetylglucosaminidase),and the relative abundance of functional genes associated with the C-cycle.This may also be related to the application of manure that increased the abundance of Gemmatimonadetes and altered ecological clusters in bacterial co-occurrence networks.Our correlation network analysis suggested that Gemmatimonadetes might be the potential hosts for C-cycling genes due to their strong positive correlation with the abundance of C-cycling genes.Overall,these findings provide new insights into soil respiration under biochar amendment and manure application in tea plantations and broaden the options for carbon sequestration in soils.展开更多
The aim of this experiment was to determine the impacts of climate change on soil profile concentrations and diffusion effluxes of methane in a rice-wheat annual rotation ecosystem in Southeastern China. We initiated ...The aim of this experiment was to determine the impacts of climate change on soil profile concentrations and diffusion effluxes of methane in a rice-wheat annual rotation ecosystem in Southeastern China. We initiated a field experiment with four treatments：ambient conditions（CKs）, CO2 concentration elevated to - 500 μmol/mol（FACE）,temperature elevated by ca. 2°C（T） and combined elevation of CO2 concentration and temperature（FACE ＋ T）. A multilevel sampling probe was designed to collect the soil gas at four different depths, namely, 7 cm, 15 cm, 30 cm and 50 cm. Methane concentrations were higher during the rice season and decreased with depth, while lower during the wheat season and increased with depth. Compared to CK, mean methane concentration was increased by 42%, 57% and 71% under the FACE, FACE ＋ T and T treatments, respectively, at the 7 cm depth during the rice season（p 〈 0.05）. Mean methane diffusion effluxes to the 7 cm depth were positive in the rice season and negative in the wheat season, resulting in the paddy field being a source and weak sink, respectively. Moreover, mean methane diffusion effluxes in the rice season were 0.94, 1.19 and 1.42 mg C/（m^2·hr） in the FACE,FACE ＋ T and T treatments, respectively, being clearly higher than that in the CK. The results indicated that elevated atmospheric CO2 concentration and temperature could significantly increase soil profile methane concentrations and their effluxes from a rice-wheat field annual rotation ecosystem（p 〈 0.05）.展开更多
Aims Elevated ozone and CO_(2) can differentially affect the performance of plant species.Variation among native,exotic and invader spe-cies in their growth and defense responses to CO_(2) and ozone may shape CO_(2) a...Aims Elevated ozone and CO_(2) can differentially affect the performance of plant species.Variation among native,exotic and invader spe-cies in their growth and defense responses to CO_(2) and ozone may shape CO_(2) and ozone effects on invasions,perhaps in part also due to variation between native and invasive populations of invaders.Methods We manipulated ozone(control or 100 ppb)and CO_(2)(ambient or 800 ppm)in a factorial greenhouse experiment in replicated cham-bers.We investigated growth and defense(tannins)of seedlings of Triadica sebifera from invasive(USA)and native(China)populations and pairs of US and China tree species within three genera(Celtis,Liquidambar and Platanus).Important Findings Overall,ozone reduced growth in ambient CO_(2) but elevated CO_(2) limited this effect.T.sebifera plants from invasive populations had higher growth than those from native populations in control con-ditions or the combination of elevated CO_(2) and ozone in which invasive populations had greater increases in growth.Their perfor-mances were similar in elevated CO_(2) because native populations were more responsive and their performances were similar with elevated ozone because invasive populations were more suscep-tible.Compared to other species,T.sebifera had high growth rates but low levels of tannin production that were insensitive to vari-ation in CO_(2) or ozone.Both China and US Platanus plants reduced tannins with increased CO_(2) and/or ozone and US Liquidambar plants increased tannins with the combination of elevated CO_(2) and ozone.The growth results suggest that intraspecific variation in T.sebifera will reduce the effects of CO_(2) or ozone alone on inva-sions but increase their combined effects.The tannin results suggest that defense responses to CO_(2) and ozone will be variable across native and exotic species.The effects of CO_(2) and ozone on growth and defense of native and exotic species indicate that the benefit or harm to species from these global change drivers is an idiosyncratic combination of species origin and genus.展开更多
Nitrogen fertilizer application has accelerated the agricultural soil N cycle while ensuring food security.Gaseous reactive N emissions from orchards,vegetables and tea plantations(OVT)are less understood than those f...Nitrogen fertilizer application has accelerated the agricultural soil N cycle while ensuring food security.Gaseous reactive N emissions from orchards,vegetables and tea plantations(OVT)are less understood than those from cereal crops.This paper presents a compilation of data on soil ammonia,nitrous oxide,and nitric oxide emissions from 1454 OVT systems at 184 unique experimental locations worldwide aiming to investigate their emission characteristics,emission factors(EF),and contribution to total farmland emissions.NH_(3)and N_(2)O emissions from orchards and N_(2)O and NO emissions from vegetable production were significantly higher in China than in the rest of the world,regardless of fertilizer application,while N_(2)O emissions from tea plantations were lower than for vegetables.The EF of NH_(3)for vegetables was close to the global mean value with urea application but significantly higher than that of orchards.The EF of N_(2)O in orchards and vegetables was comparable to the global median value,while in tea plantations,the value was 2.3 times higher than the global median value.Current estimates suggest that direct emissions of NH_(3),N_(2)O,and NO from OVT systems are equivalent to approximately a quarter,two thirds and a half of the total farmland in China,respectively.Future research needs to strengthen observational field studies in establishing standard sampling methods for gaseous N emissions and implementing knowledge-based management measures to help achieve the green development of agriculture.展开更多
基金supported by the National Key Research and Development Program of China(2022YFD2300300)the National Natural Science Foundation of China(41907072)+1 种基金the Scientific Research Foundation of Zhejiang A&F University,China(2022LFR003)the Jiangsu Agriculture Science and Technology Innovation Fund,China(CX(21)3007).
文摘Water-saving irrigation strategies can successfully alleviate methane emissions from rice fields,but significantly stimulate nitrous oxide(N_(2)O)emissions because of variations in soil oxygen level and redox potential.However,the relationship linking soil N_(2)O emissions to nitrogen functional genes during various fertilization treatments in water-saving paddy fields has rarely been investigated.Furthermore,the mitigation potential of organic fertilizer substitution on N_(2)O emissions and the microbial mechanism in rice fields must be further elucidated.Our study examined how soil N_(2)O emissions were affected by related functional microorganisms(ammonia-oxidizing archaea(AOA),ammonia-oxidizing bacteria(AOB),nirS,nirK and nosZ)to various fertilization treatments in a rice field in southeast China over two years.In this study,three fertilization regimes were applied to rice cultivation:a no nitrogen(N)(Control),an inorganic N(Ni),and an inorganic N with partial N substitution with organic manure(N_(i)+N_(o)).Over two rice-growing seasons,cumulative N_(2)O emissions averaged 0.47,4.62 and 4.08 kg ha^(−1)for the Control,Ni and N_(i)+N_(o)treatments,respectively.In comparison to the Ni treatment,the N_(i)+N_(o)fertilization regime considerably reduced soil N_(2)O emissions by 11.6%while maintaining rice yield,with a lower N_(2)O emission factor(EF)from fertilizer N of 0.95%.Nitrogen fertilization considerably raised the AOB,nirS,nirK and nosZ gene abundances,in comparison to the Control treatment.Moreover,the substitution of organic manure for inorganic N fertilizer significantly decreased AOB and nirS gene abundances and increased nosZ gene abundance.The AOB responded to N fertilization more sensitively than the AOA.Total N_(2)O emissions significantly correlated positively with AOB and nirS gene abundances while having a negative correlation with nosZ gene abundance and the nosZ/nirS ratio across N-fertilized plots.In summary,we conclude that organic manure substitution for inorganic N fertilizer decreased soil N_(2)O emissions primarily by changing the soil NO_(3)^(−)-N,pH and DOC levels,thus inhibiting the activities of ammonia oxidation in nitrification and nitrite reduction in denitrification,and strengthening N_(2)O reduction in denitrification from water-saving rice paddies.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 41775151, 41530533 and 41775152)
文摘The terrestrial carbon(C) cycle plays an important role in global climate change, but the vegetation and environmental drivers of C fluxes are poorly understood. We established a global dataset with 1194 available data across site-years including gross primary productivity(GPP), ecosystem respiration(ER), net ecosystem productivity(NEP), and relevant environmental factors to investigate the variability in GPP, ER and NEP, as well as their covariability with climate and vegetation drivers.The results indicated that both GPP and ER increased exponentially with the increase in mean annual temperature(MAT)for all biomes. Besides MAT, annual precipitation(AP) had a strong correlation with GPP(or ER) for non-wetland biomes.Maximum leaf area index(LAI) was an important factor determining C fluxes for all biomes. The variations in both GPP and ER were also associated with variations in vegetation characteristics. The model including MAT, AP and LAI explained 53%of the annual GPP variations and 48% of the annual ER variations across all biomes. The model based on MAT and LAI explained 91% of the annual GPP variations and 92.9% of the annual ER variations for the wetland sites. The effects of LAI on GPP, ER or NEP highlighted that canopy-level measurement is critical for accurately estimating ecosystem–atmosphere exchange of carbon dioxide. The present study suggests a significance of the combined effects of climate and vegetation(e.g.,LAI) drivers on C fluxes and shows that climate and LAI might influence C flux components differently in different climate regions.
基金supported by the National Key Research and Development Program of China(2017YFD0300104,2016YFD0300903,2015BAC02B02)the National Natural Science Foundation of China(32022061)+3 种基金the Special Fund for Agroscientific Research in the Public Interest(201503118,201503122)the Agricultural Science and Technology Innovation Program of CAAS(Y2016PT12,Y2016XT01)the Modern Agricultural Development of Jiangsu Province(2019-SJ-039-07)the GEF Project of Climate Smart Staple Crop Production in China(P144531)。
文摘Elevated levels of atmospheric CO_(2)(eCO_(2))promote rice growth and increase methane(CH_(4))emissions from rice paddies,because increased input of plant photosynthate to soil stimulates methanogenic archae.However,temporal trends in the effects of eCO_(2)on rice growth and CH_(4)emissions are still unclear.To investigate changes in the effects of eCO_(2)over time,we conducted a two-season pot experiment in a walk-in growth chamber.Positive effects of eCO_(2)on rice leaf photosynthetic rate,biomass,and grain yield were similar between growing seasons.However,the effects of eCO_(2)on CH_(4) emissions decreased over time.Elevated CO_(2)increased CH_(4)emissions by 48%-101%in the first growing season,but only by 28%-30%in the second growing season.We also identified the microbial process underlying the acclimation of CH4 emissions to atmospheric CO_(2)enrichment:eCO_(2)stimulated the abundance of methanotrophs more strongly in soils that had been previously exposed to eCO_(2)than in soils that had not been.These results emphasize the need for long-term eCO_(2)experiments for accurate predictions of terrestrial feedbacks.
基金supported by the National Key Research and Development Project of China(No.2017YFD0800200)the National Natural Science Foundation of China(Nos.41877093 and 41771323)+1 种基金the Fundamental Research Funds for the Central Universities of China(No.KYZ201621)the Ministry of Education 111 Project of China(No.B12009)。
文摘Bio-organic fertilizers enriched with plant growth-promoting microbes(PGPMs)have been widely used in crop fields to promote plant growth and maintain soil microbiome functions.However,their potential effects on N_(2)O emissions are of increasing concern.In this study,an in situ measurement experiment was conducted to investigate the effect of organic fertilizer containing Trichoderma guizhouense(a plant growth-promoting fungus)on soil N_(2)O emissions from a greenhouse vegetable field.The following four treatments were used:no fertilizer(control),chemical fertilizer(NPK),organic fertilizer derived from cattle manure(O),and organic fertilizer containing T.guizhouense(O+T,referring to bio-organic fertilizer).The abundances of soil N cycling-related functional genes(amoA)from ammonium-oxidizing bacteria(AOB)and archaea(AOA),as well as nirS,nirK,and nosZ,were simultaneously determined using quantitative PCR(qPCR).Compared to the NPK plot,seasonal total N_(2)O emissions decreased by 11.7%and 18.7%in the O and O+T plots,respectively,which was attributed to lower NH_(4)^(+)-N content and AOB amoA abundance in the O and O+T plots.The nosZ abundance was significantly greater in the O+T plot,whilst the AOB amoA abundance was significantly lower in the O+T plot than in the O plot.Relative to the organic fertilizer,bio-organic fertilizer application tended to decrease N_(2)O emissions by 7.9%and enhanced vegetable yield,resulting in a significant decrease in yield-scaled N_(2)O emissions.Overall,the results of this study suggested that,compared to organic and chemical fertilizers,bio-organic fertilizers containing PGPMs could benefit crop yield and mitigate N_(2)O emissions in vegetable fields.
基金National Natural Science Foundation of China(NSFC 41225003)the Ministry of Education 111 project(B12009)+2 种基金Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)China Scholarship CouncilUS-NSF(DEB 0820560).
文摘Aims Abiotic stresses may interact with each other to determine impacts on plants so that their combined impact is less than or more than additive.Increasing UV-B radiation and surface ozone(O3)are two major components of global change that may have such interactive impacts.Moreover,invasive and native populations of plants may respond differently to stresses as they can vary in primary and secondary metabolism.Methods Here,we conducted a factorial field experiment with open-top chambers assigned to an ozone treatment(ambient,100 ppb,or 150 ppb)and UV-B treatment(ambient or increased 20%).We grew seedlings of native and invasive populations of Triadica sebifera in these chambers for one growing season.Important Findings Invasive plants grew faster than native plants in ambient UV-B but they did not differ significantly in elevated UV-B.Litter production of invasive plants was especially sensitive to UV-B in a way that increased with UV-B for native plants but decreased for invasive plants which may be important for nutrient cycling.In ambient UV-B,total mass decreased as ozone increased.Total mass was lower with elevated UV-B but there was no additional impact of increasing ozone.Leaf area did not decrease with UV-B so SLA and LAR were lowest at ambient ozone levels.These results suggest that the effects of ozone will depend on UV-B conditions perhaps due to changes in foliar traits.The traits that allow invasive populations of plants to be successful invaders may make them especially sensitive to UV-B which may reduce their success in future climatic conditions.
基金National Key Research and Development Program of China(2022YFD2300300)Fundamental Research Funds for the Central Universities(XUEKEN2023036,XUEKEN2023034)+3 种基金National Natural Science Foundation of China(42007072,42177285)Jiangsu Provincial Special Project for Carbon Peak Carbon Neutrality Science and Technology Innovation(BE2022423,BE2022308)Startup Foundation for Introducing Talent of Nanjing Agricultural University(030/804028)YK thanks for the support of the Strategic Academic Leadership Program“Priority 2030”of the Kazan Federal University and the RUDN University Strategic Academic Leadership Program.
文摘Biochar has gained significant attention in agricultural and environmental research over the last two decades.This comprehensive review evaluates the effects of biochar on soil organic carbon(SOC),emission of non-CO_(2) greenhouse gases,and crop yield,including related mechanisms and major influencing factors.The impacts of biochar on SOC,methane and nitrous oxide emissions,and crop yield are controlled by biochar and soil properties and management practices.High-temperature biochar produced from lignin-rich feedstocks may decrease methane and nitrous oxide emissions in acidic soils and strengthen long-term carbon sequestration due to its stable aromatic structure.In contrast,low-temperature biochar from manure may increase crop yield in low-fertility soils.Applying biochar to farmlands in China can increase SOC content by 1.9 Pg C and reduce methane and nitrous oxide emissions by 25 and 20 Mt CO_(2)-eq year^(−1),respectively,while increasing crop yields by 19%.Despite the increasing evidence of the positive effects of biochar,future research needs to explore the potential factors that could weaken or hinder its capacity to address climate change and secure crop production.We conclude that biochar is not a universal solution for global cropland;however,targeted applications in fields,landscapes,or regional scales,especially in low fertility and sandy soils,could realize the benefits of biochar as a climate-smart measure.
基金Jiangsu Funding Program for Excellent Postdoctoral Talent(2022ZB324)China Postdoctoral Science Foundation(2023M731725)+2 种基金National Natural Science Foundation of China(42177285,42007072)Jiangsu Provincial Special Project for Carbon Peak Carbon Neutrality Science and Technology Innovation(BE2022423,BE2022308)Startup Foundation for Introducing Talent of Nanjing Agricultural University(030/804028).
文摘Applying biochar amendment and manure in tea plantation ecosystems can diminish soil acidification and degradation.However,the impact of these practices on soil respiration and associated mechanisms remains unclear.In this study,we combined a two-year field experiment and laboratory analyses based on soil properties,functional genes,and microbial co-occurrence networks to explore the determinants of soil respiration intensity in a subtropical tea plantation with biochar amendment and manure application.The results showed that the effect of biochar amendment on soil respiration was unconspicuous.Although biochar amendment increased bacterial richness and Shannon index,biochar amendment did not alter the abundance of species associated with C-cycling functional genes.Besides directly adding recalcitrant C to the soil,biochar also indirectly enhanced C sequestration by weakly increasing soil carbon dioxide(CO_(2))emissions.However,replacing mineral fertilizer with manure significantly stimulated soil respiration in the tea plantation,resulting in a 36%increase in CO_(2) emissions over two years.The increase in CO_(2) emissions under the manure treatment was mainly attributed to the increased soil labile C pool,the activity of hydrolytic enzymes(e.g.,cellobiohydrolase and acetylglucosaminidase),and the relative abundance of functional genes associated with the C-cycle.This may also be related to the application of manure that increased the abundance of Gemmatimonadetes and altered ecological clusters in bacterial co-occurrence networks.Our correlation network analysis suggested that Gemmatimonadetes might be the potential hosts for C-cycling genes due to their strong positive correlation with the abundance of C-cycling genes.Overall,these findings provide new insights into soil respiration under biochar amendment and manure application in tea plantations and broaden the options for carbon sequestration in soils.
基金supported by and the Fundamental Research Funds for the National Science Foundation of China (No. 41171238)the Ministry of Science and Technology (No. 2013BAD11B01)+1 种基金the Central Universities (No. KYTZ201404)the Nonprofit Research Foundation for Agriculture (No. 200903003)
文摘The aim of this experiment was to determine the impacts of climate change on soil profile concentrations and diffusion effluxes of methane in a rice-wheat annual rotation ecosystem in Southeastern China. We initiated a field experiment with four treatments：ambient conditions（CKs）, CO2 concentration elevated to - 500 μmol/mol（FACE）,temperature elevated by ca. 2°C（T） and combined elevation of CO2 concentration and temperature（FACE ＋ T）. A multilevel sampling probe was designed to collect the soil gas at four different depths, namely, 7 cm, 15 cm, 30 cm and 50 cm. Methane concentrations were higher during the rice season and decreased with depth, while lower during the wheat season and increased with depth. Compared to CK, mean methane concentration was increased by 42%, 57% and 71% under the FACE, FACE ＋ T and T treatments, respectively, at the 7 cm depth during the rice season（p 〈 0.05）. Mean methane diffusion effluxes to the 7 cm depth were positive in the rice season and negative in the wheat season, resulting in the paddy field being a source and weak sink, respectively. Moreover, mean methane diffusion effluxes in the rice season were 0.94, 1.19 and 1.42 mg C/（m^2·hr） in the FACE,FACE ＋ T and T treatments, respectively, being clearly higher than that in the CK. The results indicated that elevated atmospheric CO2 concentration and temperature could significantly increase soil profile methane concentrations and their effluxes from a rice-wheat field annual rotation ecosystem（p 〈 0.05）.
基金The Ministry of Education 111 project(B12009)China Scholarship CouncilUS-NSF(DEB 0820560).
文摘Aims Elevated ozone and CO_(2) can differentially affect the performance of plant species.Variation among native,exotic and invader spe-cies in their growth and defense responses to CO_(2) and ozone may shape CO_(2) and ozone effects on invasions,perhaps in part also due to variation between native and invasive populations of invaders.Methods We manipulated ozone(control or 100 ppb)and CO_(2)(ambient or 800 ppm)in a factorial greenhouse experiment in replicated cham-bers.We investigated growth and defense(tannins)of seedlings of Triadica sebifera from invasive(USA)and native(China)populations and pairs of US and China tree species within three genera(Celtis,Liquidambar and Platanus).Important Findings Overall,ozone reduced growth in ambient CO_(2) but elevated CO_(2) limited this effect.T.sebifera plants from invasive populations had higher growth than those from native populations in control con-ditions or the combination of elevated CO_(2) and ozone in which invasive populations had greater increases in growth.Their perfor-mances were similar in elevated CO_(2) because native populations were more responsive and their performances were similar with elevated ozone because invasive populations were more suscep-tible.Compared to other species,T.sebifera had high growth rates but low levels of tannin production that were insensitive to vari-ation in CO_(2) or ozone.Both China and US Platanus plants reduced tannins with increased CO_(2) and/or ozone and US Liquidambar plants increased tannins with the combination of elevated CO_(2) and ozone.The growth results suggest that intraspecific variation in T.sebifera will reduce the effects of CO_(2) or ozone alone on inva-sions but increase their combined effects.The tannin results suggest that defense responses to CO_(2) and ozone will be variable across native and exotic species.The effects of CO_(2) and ozone on growth and defense of native and exotic species indicate that the benefit or harm to species from these global change drivers is an idiosyncratic combination of species origin and genus.
基金financially supported by the Jiangsu Provincial Special Project for Carbon Peak Carbon Neutrality Science and Technology Innovation(BE2022423,BE2022308)the National Natural Science Foundation of China(42177285,42007072)the Startup Foundation for Introducing Talent of Nanjing Agricultural University(030/804028)。
文摘Nitrogen fertilizer application has accelerated the agricultural soil N cycle while ensuring food security.Gaseous reactive N emissions from orchards,vegetables and tea plantations(OVT)are less understood than those from cereal crops.This paper presents a compilation of data on soil ammonia,nitrous oxide,and nitric oxide emissions from 1454 OVT systems at 184 unique experimental locations worldwide aiming to investigate their emission characteristics,emission factors(EF),and contribution to total farmland emissions.NH_(3)and N_(2)O emissions from orchards and N_(2)O and NO emissions from vegetable production were significantly higher in China than in the rest of the world,regardless of fertilizer application,while N_(2)O emissions from tea plantations were lower than for vegetables.The EF of NH_(3)for vegetables was close to the global mean value with urea application but significantly higher than that of orchards.The EF of N_(2)O in orchards and vegetables was comparable to the global median value,while in tea plantations,the value was 2.3 times higher than the global median value.Current estimates suggest that direct emissions of NH_(3),N_(2)O,and NO from OVT systems are equivalent to approximately a quarter,two thirds and a half of the total farmland in China,respectively.Future research needs to strengthen observational field studies in establishing standard sampling methods for gaseous N emissions and implementing knowledge-based management measures to help achieve the green development of agriculture.
