Wetland ecosystems have become one of the long-term solutions for mitigating global climate change due to their strong carbon sequestration potential.However,the key carbon cycle processes in wetland ecosystems still ...Wetland ecosystems have become one of the long-term solutions for mitigating global climate change due to their strong carbon sequestration potential.However,the key carbon cycle processes in wetland ecosystems still lack a systematic summary.In the context of wetland protection and restoration,there is still a lack of consensus on the technical pathways to realize carbon sink multiplication in wetland ecosystems.In this paper,the key processes of carbon cycle,such as photosynthetic carbon uptake,microbial carbon decomposition and carbon deposition and burial,are sorted out and summarized in four major wetland types,namely,swamp and peat wetlands,river and riparian wetlands,lake and lakeshore wetlands,and estuarine and coastal wetlands.Based on the key processes of carbon cycle,three technological pathways for carbon sink multiplication are proposed,including,vegetation carbon sequestration and sink enhancement technology,soil carbon emission reduction technology and carbon deposition and burial technology.The key technologies under each pathway are further refined.And the carbon sink effects of the carbon sink technologies in different wetland types are qualitatively described.Also,wetland protection and restoration methods in corresponding regions are given in the light of the regional characteristics of wetlands in China.This will provide a scientific basis for the strategy of doubling the carbon sinks of China′s wetland ecosystems.展开更多
Since the 1980s,the widespread use of N fertilizer has not only resulted in a strong increase in agricultural productivity but also caused a number of environmental problems,induced by excess reactive N emissions.A ra...Since the 1980s,the widespread use of N fertilizer has not only resulted in a strong increase in agricultural productivity but also caused a number of environmental problems,induced by excess reactive N emissions.A range of approaches to improve N management for increased agricultural production together with reduced environmental impacts has been proposed.The 4R principles(right product,right amount,right time and right place)for N fertilizer application have been essential for improving crop productivity and N use efficiency while reducing N losses.For example,site-specific N management(as part of 4R practice)reduced N fertilizer use by 32%and increased yield by 5%in China.However,it has not been enough to overcome the challenge of producing more food with reduced impact on the environment and health.This paper proposes a new framework of food-chainnitrogen-management(FCNM).This involves good N management including the recycling of organic manures,optimized crop and animal production and improved human diets,with the aim of maximizing resource use efficiency and minimizing environmental emissions.FCNM could meet future challenges for food demand,resource sustainability and environmental safety,key issues for green agricultural transformation in China and other countries.展开更多
Grasslands are globally-important ecosystems providing critical ecosystem services.The species composition and characteristics of grasslands vary considerably across the planet with a wide variety of different grassla...Grasslands are globally-important ecosystems providing critical ecosystem services.The species composition and characteristics of grasslands vary considerably across the planet with a wide variety of different grasslands found.However,in many regions grasslands have been impacted by atmospheric nitrogen deposition originating from anthropogenic activities with effects on productivity,species composition and diversity widely reported.Impacts vary across grassland habitats but many show declines in species richness and increases in biomass production related to soil eutrophication and acidification.At a continental level,there is considerable variation in the research effort that has been put into understanding the impacts of nitrogen deposition.In Europe,North America and parts of Asia,although there are unanswered research questions,there is a good understanding of N deposition impacts in most grassland habitats.This is not the case in other regions with large knowledge gaps in some parts of the world.This paper reviews the impacts of N deposition on grasslands around the world,highlighting recent advances and areas where research is still needed.展开更多
●We studied the effect of nitrogen and biochar on CO_(2) emission from SOC and SIC.●Nitrogen increased SIC-derived CO_(2) by 41%but decreased SOC-derived CO_(2) by 20%.●Biochar reduced total soil-derived CO_(2) by ...●We studied the effect of nitrogen and biochar on CO_(2) emission from SOC and SIC.●Nitrogen increased SIC-derived CO_(2) by 41%but decreased SOC-derived CO_(2) by 20%.●Biochar reduced total soil-derived CO_(2) by neutralizing nitrogen-induced acidity.●We proposed a method for 3-or 4-source partitioning CO_(2) emission from calcareous soils.Biochar addition generally increases the alkalinity regeneration to resist soil acidification driven by nitrogen(N)fertilization.Calcareous soils contain soil organic carbon(SOC)and inorganic C(SIC).Owing to technical limitations in three-source partitioning CO_(2),how biochar addition affects SOC-and SIC-derived CO_(2) emission has not been clarified yet.Therefore,we conducted a 70-day incubation experiment of ammonium-N and maize-straw-derived biochar additions to investigate the N plus biochar impacts on SOC-and SIC-derived CO_(2) emission.Over the 70-day incubation,we found that the N-only addition increased the SIC-derived CO_(2) emission by approximately 41%compared with the control,but decreased the SOC-derived CO_(2) emission by approximately 20%.This suggests that the distinct responses of SIC-and SOC-derived CO_(2) emission to N-only addition come from N-induced acidification and preferential substrate(N)utilization of soil microorganisms,respectively.Compared with N-only addition,N plus biochar addition decreased the SIC-derived CO_(2) emission by 17%−20%during the first 20 days of incubation,but increased it by 54%during the next 50 days.This result suggested that biochar addition reduced the SIC-derived CO_(2) emission likely due to the alkalization capacity of biochar exceeding the acidification capacity of ammonium-N in the short term,but it may increase the SIC-derived CO_(2) emission induced by the weak acidity produced from biochar mineralization in the long term.This study is helpful to improve the quantification of CO_(2) emission from calcareous soils.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.31988102)。
文摘Wetland ecosystems have become one of the long-term solutions for mitigating global climate change due to their strong carbon sequestration potential.However,the key carbon cycle processes in wetland ecosystems still lack a systematic summary.In the context of wetland protection and restoration,there is still a lack of consensus on the technical pathways to realize carbon sink multiplication in wetland ecosystems.In this paper,the key processes of carbon cycle,such as photosynthetic carbon uptake,microbial carbon decomposition and carbon deposition and burial,are sorted out and summarized in four major wetland types,namely,swamp and peat wetlands,river and riparian wetlands,lake and lakeshore wetlands,and estuarine and coastal wetlands.Based on the key processes of carbon cycle,three technological pathways for carbon sink multiplication are proposed,including,vegetation carbon sequestration and sink enhancement technology,soil carbon emission reduction technology and carbon deposition and burial technology.The key technologies under each pathway are further refined.And the carbon sink effects of the carbon sink technologies in different wetland types are qualitatively described.Also,wetland protection and restoration methods in corresponding regions are given in the light of the regional characteristics of wetlands in China.This will provide a scientific basis for the strategy of doubling the carbon sinks of China′s wetland ecosystems.
基金supported by the National Natural Science Foundation of China (41425007)the National Key R&D Project of China (2018YFC0213302)+3 种基金the UK-China Virtual Joint Centre for Improved Nitrogen AgronomyDeutsche Forschungsgemeinschaft (German Research Foundation)Sino-German International Research Training Group AMAIZE-P (328017493/GRK 2366)the High-level Team Project of China Agricultural University。
文摘Since the 1980s,the widespread use of N fertilizer has not only resulted in a strong increase in agricultural productivity but also caused a number of environmental problems,induced by excess reactive N emissions.A range of approaches to improve N management for increased agricultural production together with reduced environmental impacts has been proposed.The 4R principles(right product,right amount,right time and right place)for N fertilizer application have been essential for improving crop productivity and N use efficiency while reducing N losses.For example,site-specific N management(as part of 4R practice)reduced N fertilizer use by 32%and increased yield by 5%in China.However,it has not been enough to overcome the challenge of producing more food with reduced impact on the environment and health.This paper proposes a new framework of food-chainnitrogen-management(FCNM).This involves good N management including the recycling of organic manures,optimized crop and animal production and improved human diets,with the aim of maximizing resource use efficiency and minimizing environmental emissions.FCNM could meet future challenges for food demand,resource sustainability and environmental safety,key issues for green agricultural transformation in China and other countries.
文摘Grasslands are globally-important ecosystems providing critical ecosystem services.The species composition and characteristics of grasslands vary considerably across the planet with a wide variety of different grasslands found.However,in many regions grasslands have been impacted by atmospheric nitrogen deposition originating from anthropogenic activities with effects on productivity,species composition and diversity widely reported.Impacts vary across grassland habitats but many show declines in species richness and increases in biomass production related to soil eutrophication and acidification.At a continental level,there is considerable variation in the research effort that has been put into understanding the impacts of nitrogen deposition.In Europe,North America and parts of Asia,although there are unanswered research questions,there is a good understanding of N deposition impacts in most grassland habitats.This is not the case in other regions with large knowledge gaps in some parts of the world.This paper reviews the impacts of N deposition on grasslands around the world,highlighting recent advances and areas where research is still needed.
基金supported by the National Natural Science Foundation of China(32072518 and 42141006)the Natural Science Foundation of Shandong Province(ZR2020QD042).
文摘●We studied the effect of nitrogen and biochar on CO_(2) emission from SOC and SIC.●Nitrogen increased SIC-derived CO_(2) by 41%but decreased SOC-derived CO_(2) by 20%.●Biochar reduced total soil-derived CO_(2) by neutralizing nitrogen-induced acidity.●We proposed a method for 3-or 4-source partitioning CO_(2) emission from calcareous soils.Biochar addition generally increases the alkalinity regeneration to resist soil acidification driven by nitrogen(N)fertilization.Calcareous soils contain soil organic carbon(SOC)and inorganic C(SIC).Owing to technical limitations in three-source partitioning CO_(2),how biochar addition affects SOC-and SIC-derived CO_(2) emission has not been clarified yet.Therefore,we conducted a 70-day incubation experiment of ammonium-N and maize-straw-derived biochar additions to investigate the N plus biochar impacts on SOC-and SIC-derived CO_(2) emission.Over the 70-day incubation,we found that the N-only addition increased the SIC-derived CO_(2) emission by approximately 41%compared with the control,but decreased the SOC-derived CO_(2) emission by approximately 20%.This suggests that the distinct responses of SIC-and SOC-derived CO_(2) emission to N-only addition come from N-induced acidification and preferential substrate(N)utilization of soil microorganisms,respectively.Compared with N-only addition,N plus biochar addition decreased the SIC-derived CO_(2) emission by 17%−20%during the first 20 days of incubation,but increased it by 54%during the next 50 days.This result suggested that biochar addition reduced the SIC-derived CO_(2) emission likely due to the alkalization capacity of biochar exceeding the acidification capacity of ammonium-N in the short term,but it may increase the SIC-derived CO_(2) emission induced by the weak acidity produced from biochar mineralization in the long term.This study is helpful to improve the quantification of CO_(2) emission from calcareous soils.
