Nitrogen(N)loss is a major limiting factor affecting agricultural productivity in saline-alkali soils,with ammonia(NH_(3))volatilization and N leaching being the main sources of N loss.In this study,the dynamics of NH...Nitrogen(N)loss is a major limiting factor affecting agricultural productivity in saline-alkali soils,with ammonia(NH_(3))volatilization and N leaching being the main sources of N loss.In this study,the dynamics of NH_(3)volatilization were measured using the open static chamber method(sponge sampling),alongside the distribution of^(15)N and NO_(3)^(-)-N concentrations in layers,in a 30-cm soil column experiment with vermicompost addition after incorporation of^(15)N-labeled urea in the upper layer(0-10 cm)of a saline-alkali soil.Destructive sampling was conducted on days 20 and 60 of the column experiment to investigate the influencing factors of NH_(3)volatilization and^(15)N/NO_(3)^(-)retention,respectively.The results showed that the addition of vermicompost to saline-alkali soil decreased cumulative NH_(3)volatilization by 45.1%,decreased the^(15)N concentration in the bottom layer(20-30 cm)by 17.1%,and increased the^(15)N concentration in the upper soil by 48.7%.Vermicompost regulated the abundances of amoA,amoC,and nxrA genes,which can decrease NH_(3)volatilization by converting substrate NH_(4)^(+)to NO_(3)^(-).Additionally,Ca^(2+)adsorption is enhanced(increased by 6.2%)by increasing soil cation exchange capacity(increased by 20.6%),thus replacing the adsorption of Na^(+)(decreased by 13.8%)and decreasing the desorption of NH_(4)^(+).Vermicompost enhanced the adsorption of NO_(3)^(-)by increasing Ca^(2+)and Mg^(2+)and decreasing Cl-by 30.4%in the upper soil.This study concluded that vermicompost addition can inhibit N loss by reducing NH_(3)volatilization and improving^(15)N/NO_(3)^(-)retention in saline-alkali soils.展开更多
The response of N_(2)O emissions to nitrogen(N)addition is usually positive,but its response to phosphorus(P)addition varies,and the underlying mechanisms for the changes in N_(2)O emissions remain unclear.We conducte...The response of N_(2)O emissions to nitrogen(N)addition is usually positive,but its response to phosphorus(P)addition varies,and the underlying mechanisms for the changes in N_(2)O emissions remain unclear.We conducted field studies to examine the response of N_(2)O emissions to N and P addition over two years in three typical alpine grasslands,alpine meadow(AM),alpine steppe(AS),and alpine cultivated grassland(CG)on the Qinghai-Tibet Plateau(QTP).Our results showed consistent increases in N_(2)O emissions under N addition alone or with P addition,and insignificant change in N_(2)O emissions under P addition alone in all three grasslands.N addition increased N_(2)O emissions directly in AM,by lowering soil pH in AS,and by lowering abundance of denitrification genes in CG.N and P co-addition increased N_(2)O emissions in AM and AS but only showed an interactive effect in AM.P addition enhanced the increase in N_(2)O emissions caused by N addition mainly by promoting plant growth in AM.Overall,our results illustrate that short-term P addition cannot alleviate the stimulation of N_(2)O emissions by N deposition in alpine grassland ecosystems,and may even further stimulate N_(2)O emissions.展开更多
The availability of nitrogen(N)is crucial for both the productivity of terrestrial and aquatic ecosystems globally.However,the overuse of artificial fertilizers and the energy required to fix nitrogen have pushed the ...The availability of nitrogen(N)is crucial for both the productivity of terrestrial and aquatic ecosystems globally.However,the overuse of artificial fertilizers and the energy required to fix nitrogen have pushed the global nitrogen cycle(N-cycle)past its safe operating limits,leading to severe nitrogen pollution and the production of significant amounts of greenhouse gas nitrous oxide(N2O).The anaerobic ammonium oxidation(anammox)mechanism can counteract the release of ammonium and N2O in many oxygenlimited situations,assisting in the restoration of the homeostasis of the Earth’s N biogeochemistry.In this work,we looked into the characteristics of the anammox hotspots’distribution across various types of ecosystems worldwide.Anammox hotspots are present at diverse oxic-anoxic interfaces in terrestrial systems,and they are most prevalent at the oxic-anoxic transition zone in aquatic ecosystems.Based on the discovery of an anammox hotspot capable of oxidizing ammonium anoxically into N2 without N2O by-product,we then designed an innovative concept and technical routes of nature-based anammox hotspot geoengineering for climate change,biodiversity loss,and efficient utilization of water resources.After 15 years of actual use,anammox hotspot geoengineering has proven to be effective in ensuring clean drinking water,regulating the climate,fostering plant and animal diversity,and enhancing longterm environmental quality.The sustainable biogeoengineering of anammox could be a workable natural remedy to resolve the conflicts between environmental pollution and food security connected to N management.展开更多
Population growth and growing demand for livestock products produce large amounts of manure,which can be harnessed to maintain soil sustainability and crop productivity.However,the impacts of excessive manure applicat...Population growth and growing demand for livestock products produce large amounts of manure,which can be harnessed to maintain soil sustainability and crop productivity.However,the impacts of excessive manure application on crop yields,nitrogen(N)-cycling processes and microorganisms remain unknown.Here,we explored the effects of 20-year of excessive rates(18 and 27 Mg ha^(–1)yr^(–1))of pig manure application on peanut crop yields,soil nutrient contents,N-cycling processes and the abundance of N-cycling microorganisms in an acidic Ultisol in summer and winter,compared with none and a regular rate(9 Mg ha^(–1)yr^(–1))of pig manure application.Long-term excessive pig manure application,especially at the high-rate,significantly increased soil nutrient contents,the abundance of N-cycling functional genes,potential nitrification and denitrification activity,while it had a weaker effect on peanut yield and plant biomass.Compared with manure application,seasonality had a much weaker effect on N-cycling gene abundance.Random forest analysis showed that available phosphorus(AP)content was the primary predictor for N-cycling gene abundance,with significant and positive associations with all tested N-cycling genes.Our study clearly illustrated that excessive manure application would increase N-cycling gene abundance and potential N loss with relatively weak promotion of crop yields,providing significant implications for sustainable agriculture in the acidic Ultisols.展开更多
During the process of landslide, its dynamic mechanism is important to understand and predict these kinds of natural hazard. In this paper, a new method, based on concepts of complex networks, has been proposed to inv...During the process of landslide, its dynamic mechanism is important to understand and predict these kinds of natural hazard. In this paper, a new method, based on concepts of complex networks, has been proposed to investigate the evolution of contact networks in mesoscale during the sliding process of slope. A slope model was established using the discrete element method (DEM), and influences of inter-particle frictional coefficients with four different values on?dynamic landslides were studied. Both macroscopic analysis on slope?landslide?and mesoanalysis on structure evolution of contact networks, including the?average degree, clustering coefficient?and N-cycle, were done during the process?of landslide. The analysis results demonstrate that: 1) with increasing inter-particle?frictional coefficients, the displacement of slope decreases and the stable angle of slope post-failure increases, which is smaller than the peak internal frictional angle;2) the average degree decreases with the increase of inter-particle frictional coefficient. When the displacement at the toe of the slope is smaller,?the average degree there changes more greatly with increasing inter-particle?frictional coefficient;3) during the initial stage of landslide, the clustering coefficient?reduces sharply, which may leads to easily slide of slope. As the landslide?going?on, however, the clustering coefficient?increases denoting increasing stability?with?increasing inter-particle frictional coefficients. When the inter-particle?frictional coefficient is smaller than 0.3, its variation can affect the clustering coefficient?and stable inclination of slope post-failure greatly;and 4) the number of?3-cycle increases, but 4-cycle and 5-cycle decrease with increasing inter-particle frictional coefficients.展开更多
Agriculture has increased the release of reactive nitrogen to the environment due to crops’low nitrogen-use efficiency(NUE)after the application of nitrogen-fertilisers.Practices like the use of stabilized-fertiliser...Agriculture has increased the release of reactive nitrogen to the environment due to crops’low nitrogen-use efficiency(NUE)after the application of nitrogen-fertilisers.Practices like the use of stabilized-fertilisers with nitrification inhibitors such as DMPP(3,4-dimethylpyrazole phosphate)have been adopted to reduce nitrogen losses.Otherwise,cover crops can be used in crop-rotation-strategies to reduce soil nitrogen pollution and benefit the following culture.Sorghum(Sorghum bicolor)could be a good candidate as it is drought tolerant and its culture can reduce nitrogen losses derived from nitrification because it exudates biological nitrification inhibitors(BNIs).This work aimed to evaluate the effect of fallow-wheat and sorghum cover crop-wheat rotations on N_(2)O emissions and the grain yield of winter wheat crop.In addition,the suitability of DMPP addition was also analyzed.The use of sorghum as a cover crop might not be a suitable option to mitigate nitrogen losses in the subsequent crop.Although sorghum–wheat rotation was able to reduce 22%the abundance of amoA,it presented an increment of 77%in cumulative N_(2)O emissions compared to fallow–wheat rotation,which was probably related to a greater abundance of heterotrophic-denitrification genes.On the other hand,the application of DMPP avoided the growth of ammonia-oxidizing bacteria and maintained the N_(2)O emissions at the levels of unfertilized-soils in both rotations.As a conclusion,the use of DMPP would be recommendable regardless of the rotation since it maintains NH_(4)^(+)in the soil for longer and mitigates the impact of the crop residues on nitrogen soil dynamics.展开更多
The soil nitrogen cycle is primarily driven by microbial communities and provides reactive nitrogen for all organisms.With the increasing impact of human activities and climate change,biogeographical explicit patterns...The soil nitrogen cycle is primarily driven by microbial communities and provides reactive nitrogen for all organisms.With the increasing impact of human activities and climate change,biogeographical explicit patterns of soil microbial nitrogen-cycling genes and their associations with nitrogen fluxes are still unknown at the global scale.By conducting a global analysis of 1198 soil metagenomic samples,we verified that agricultural land displayed lower microbial richness and diversity values than did the other habitats.We generated a global map of the genetic potential of N cycle processes in soil and revealed that denitrification and dissimilatory nitrate reduction processes are greater in agricultural centers than in non-agricultural areas and are mainly driven by the mean annual temperature and nitrogen fertilizer application.Soil nitrous oxide(N2O)emissions are greater in agricultural land than in other habitats and are mainly driven by nitrogen fertilizer application,which is consistent with the genetic potential of N2O synthesis.Our study improves the theoretical framework for predicting global soil nitrogen cycling potential under complex variables and highlights the influence weight of human activities and climate factors.We strongly emphasize the importance of rationally applying nitrogen fertilizers to balance agricultural production,ecological health and climate change.展开更多
基金supported by the National Key R&D Program of China(No.2021YFD1900901)the National Natural Science Foundation of China(No.32271711).
文摘Nitrogen(N)loss is a major limiting factor affecting agricultural productivity in saline-alkali soils,with ammonia(NH_(3))volatilization and N leaching being the main sources of N loss.In this study,the dynamics of NH_(3)volatilization were measured using the open static chamber method(sponge sampling),alongside the distribution of^(15)N and NO_(3)^(-)-N concentrations in layers,in a 30-cm soil column experiment with vermicompost addition after incorporation of^(15)N-labeled urea in the upper layer(0-10 cm)of a saline-alkali soil.Destructive sampling was conducted on days 20 and 60 of the column experiment to investigate the influencing factors of NH_(3)volatilization and^(15)N/NO_(3)^(-)retention,respectively.The results showed that the addition of vermicompost to saline-alkali soil decreased cumulative NH_(3)volatilization by 45.1%,decreased the^(15)N concentration in the bottom layer(20-30 cm)by 17.1%,and increased the^(15)N concentration in the upper soil by 48.7%.Vermicompost regulated the abundances of amoA,amoC,and nxrA genes,which can decrease NH_(3)volatilization by converting substrate NH_(4)^(+)to NO_(3)^(-).Additionally,Ca^(2+)adsorption is enhanced(increased by 6.2%)by increasing soil cation exchange capacity(increased by 20.6%),thus replacing the adsorption of Na^(+)(decreased by 13.8%)and decreasing the desorption of NH_(4)^(+).Vermicompost enhanced the adsorption of NO_(3)^(-)by increasing Ca^(2+)and Mg^(2+)and decreasing Cl-by 30.4%in the upper soil.This study concluded that vermicompost addition can inhibit N loss by reducing NH_(3)volatilization and improving^(15)N/NO_(3)^(-)retention in saline-alkali soils.
基金funded by the National Key R&D Program of China(2021YFE0112400 and 2023YFF1304303)the National Natural Science Foundation of China(32361143870 and 32101315)。
文摘The response of N_(2)O emissions to nitrogen(N)addition is usually positive,but its response to phosphorus(P)addition varies,and the underlying mechanisms for the changes in N_(2)O emissions remain unclear.We conducted field studies to examine the response of N_(2)O emissions to N and P addition over two years in three typical alpine grasslands,alpine meadow(AM),alpine steppe(AS),and alpine cultivated grassland(CG)on the Qinghai-Tibet Plateau(QTP).Our results showed consistent increases in N_(2)O emissions under N addition alone or with P addition,and insignificant change in N_(2)O emissions under P addition alone in all three grasslands.N addition increased N_(2)O emissions directly in AM,by lowering soil pH in AS,and by lowering abundance of denitrification genes in CG.N and P co-addition increased N_(2)O emissions in AM and AS but only showed an interactive effect in AM.P addition enhanced the increase in N_(2)O emissions caused by N addition mainly by promoting plant growth in AM.Overall,our results illustrate that short-term P addition cannot alleviate the stimulation of N_(2)O emissions by N deposition in alpine grassland ecosystems,and may even further stimulate N_(2)O emissions.
基金supported by the National Natural Science Foundation of China(91851204 and 42021005)the Special project of eco-environmental technology for peak carbon dioxide emissions and carbon neutrality(RCEES-TDZ-2021-20).
文摘The availability of nitrogen(N)is crucial for both the productivity of terrestrial and aquatic ecosystems globally.However,the overuse of artificial fertilizers and the energy required to fix nitrogen have pushed the global nitrogen cycle(N-cycle)past its safe operating limits,leading to severe nitrogen pollution and the production of significant amounts of greenhouse gas nitrous oxide(N2O).The anaerobic ammonium oxidation(anammox)mechanism can counteract the release of ammonium and N2O in many oxygenlimited situations,assisting in the restoration of the homeostasis of the Earth’s N biogeochemistry.In this work,we looked into the characteristics of the anammox hotspots’distribution across various types of ecosystems worldwide.Anammox hotspots are present at diverse oxic-anoxic interfaces in terrestrial systems,and they are most prevalent at the oxic-anoxic transition zone in aquatic ecosystems.Based on the discovery of an anammox hotspot capable of oxidizing ammonium anoxically into N2 without N2O by-product,we then designed an innovative concept and technical routes of nature-based anammox hotspot geoengineering for climate change,biodiversity loss,and efficient utilization of water resources.After 15 years of actual use,anammox hotspot geoengineering has proven to be effective in ensuring clean drinking water,regulating the climate,fostering plant and animal diversity,and enhancing longterm environmental quality.The sustainable biogeoengineering of anammox could be a workable natural remedy to resolve the conflicts between environmental pollution and food security connected to N management.
基金supported by the National Natural Science Foundation of China(41930756 and 42077041)。
文摘Population growth and growing demand for livestock products produce large amounts of manure,which can be harnessed to maintain soil sustainability and crop productivity.However,the impacts of excessive manure application on crop yields,nitrogen(N)-cycling processes and microorganisms remain unknown.Here,we explored the effects of 20-year of excessive rates(18 and 27 Mg ha^(–1)yr^(–1))of pig manure application on peanut crop yields,soil nutrient contents,N-cycling processes and the abundance of N-cycling microorganisms in an acidic Ultisol in summer and winter,compared with none and a regular rate(9 Mg ha^(–1)yr^(–1))of pig manure application.Long-term excessive pig manure application,especially at the high-rate,significantly increased soil nutrient contents,the abundance of N-cycling functional genes,potential nitrification and denitrification activity,while it had a weaker effect on peanut yield and plant biomass.Compared with manure application,seasonality had a much weaker effect on N-cycling gene abundance.Random forest analysis showed that available phosphorus(AP)content was the primary predictor for N-cycling gene abundance,with significant and positive associations with all tested N-cycling genes.Our study clearly illustrated that excessive manure application would increase N-cycling gene abundance and potential N loss with relatively weak promotion of crop yields,providing significant implications for sustainable agriculture in the acidic Ultisols.
文摘During the process of landslide, its dynamic mechanism is important to understand and predict these kinds of natural hazard. In this paper, a new method, based on concepts of complex networks, has been proposed to investigate the evolution of contact networks in mesoscale during the sliding process of slope. A slope model was established using the discrete element method (DEM), and influences of inter-particle frictional coefficients with four different values on?dynamic landslides were studied. Both macroscopic analysis on slope?landslide?and mesoanalysis on structure evolution of contact networks, including the?average degree, clustering coefficient?and N-cycle, were done during the process?of landslide. The analysis results demonstrate that: 1) with increasing inter-particle?frictional coefficients, the displacement of slope decreases and the stable angle of slope post-failure increases, which is smaller than the peak internal frictional angle;2) the average degree decreases with the increase of inter-particle frictional coefficient. When the displacement at the toe of the slope is smaller,?the average degree there changes more greatly with increasing inter-particle?frictional coefficient;3) during the initial stage of landslide, the clustering coefficient?reduces sharply, which may leads to easily slide of slope. As the landslide?going?on, however, the clustering coefficient?increases denoting increasing stability?with?increasing inter-particle frictional coefficients. When the inter-particle?frictional coefficient is smaller than 0.3, its variation can affect the clustering coefficient?and stable inclination of slope post-failure greatly;and 4) the number of?3-cycle increases, but 4-cycle and 5-cycle decrease with increasing inter-particle frictional coefficients.
基金supported by the Spanish Government(RTI2018-094623-B-C21 and C22 MCIU/AEI/FEDER,UE)the Basque Government(IT-932-16).Dr.Adrian Bozal-Leorri held a grant from the Basque Government(PRE-2020-2-0142)Dr.Mario Corrochano-Monsalve held a grant from the Ministry of Economy and Business of the Spanish Government(BES-2016-076725).
文摘Agriculture has increased the release of reactive nitrogen to the environment due to crops’low nitrogen-use efficiency(NUE)after the application of nitrogen-fertilisers.Practices like the use of stabilized-fertilisers with nitrification inhibitors such as DMPP(3,4-dimethylpyrazole phosphate)have been adopted to reduce nitrogen losses.Otherwise,cover crops can be used in crop-rotation-strategies to reduce soil nitrogen pollution and benefit the following culture.Sorghum(Sorghum bicolor)could be a good candidate as it is drought tolerant and its culture can reduce nitrogen losses derived from nitrification because it exudates biological nitrification inhibitors(BNIs).This work aimed to evaluate the effect of fallow-wheat and sorghum cover crop-wheat rotations on N_(2)O emissions and the grain yield of winter wheat crop.In addition,the suitability of DMPP addition was also analyzed.The use of sorghum as a cover crop might not be a suitable option to mitigate nitrogen losses in the subsequent crop.Although sorghum–wheat rotation was able to reduce 22%the abundance of amoA,it presented an increment of 77%in cumulative N_(2)O emissions compared to fallow–wheat rotation,which was probably related to a greater abundance of heterotrophic-denitrification genes.On the other hand,the application of DMPP avoided the growth of ammonia-oxidizing bacteria and maintained the N_(2)O emissions at the levels of unfertilized-soils in both rotations.As a conclusion,the use of DMPP would be recommendable regardless of the rotation since it maintains NH_(4)^(+)in the soil for longer and mitigates the impact of the crop residues on nitrogen soil dynamics.
基金supported by the National Natural Science Foundation of China(Grant Nos.42377107,22376187 and 42307158).
文摘The soil nitrogen cycle is primarily driven by microbial communities and provides reactive nitrogen for all organisms.With the increasing impact of human activities and climate change,biogeographical explicit patterns of soil microbial nitrogen-cycling genes and their associations with nitrogen fluxes are still unknown at the global scale.By conducting a global analysis of 1198 soil metagenomic samples,we verified that agricultural land displayed lower microbial richness and diversity values than did the other habitats.We generated a global map of the genetic potential of N cycle processes in soil and revealed that denitrification and dissimilatory nitrate reduction processes are greater in agricultural centers than in non-agricultural areas and are mainly driven by the mean annual temperature and nitrogen fertilizer application.Soil nitrous oxide(N2O)emissions are greater in agricultural land than in other habitats and are mainly driven by nitrogen fertilizer application,which is consistent with the genetic potential of N2O synthesis.Our study improves the theoretical framework for predicting global soil nitrogen cycling potential under complex variables and highlights the influence weight of human activities and climate factors.We strongly emphasize the importance of rationally applying nitrogen fertilizers to balance agricultural production,ecological health and climate change.
