【目的】明确不同土地利用方式土壤氧化亚氮(N_(2)O)排放系数的差异并评估区域N_(2)O排放,为评估南方红壤丘陵区N_(2)O排放清单提供基础数据和参考依据。【方法】选择南方红壤丘陵区4种常见的土地利用方式(油茶林、旱地农田、稻田和松...【目的】明确不同土地利用方式土壤氧化亚氮(N_(2)O)排放系数的差异并评估区域N_(2)O排放,为评估南方红壤丘陵区N_(2)O排放清单提供基础数据和参考依据。【方法】选择南方红壤丘陵区4种常见的土地利用方式(油茶林、旱地农田、稻田和松林),通过分析土壤不施肥与施氮肥时N_(2)O排放速率和排放量的差异,计算排放系数,并用^(15)N同位素标记方法探究硝化作用和反硝化作用对土壤排放N_(2)O的相对贡献。【结果】不同土地利用方式土壤理化性质差异明显,稻田全氮含量最高(2.22 g/kg),显著高于其他3种土地利用方式土壤(P<0.05,下同)。土壤不施肥时,N_(2)O排放速率在0~227.80μg/(kg·h),施氮量为200 kg N/ha时,N_(2)O排放速率在0~4213.27μg/(kg·h)。4种土地利用方式的土壤N_(2)O排放系数均随土壤孔隙含水量(WPFS)增加而增加,WPFS为75%时,稻田、旱地农田、油茶林和松林土壤N_(2)O排放系数分别为2.47%、0.39%、2.31%和0.91%。4种土地利用方式土壤N_(2)O排放系数主要受全氮含量影响,N_(2)O累积排放量均与潜在反硝化潜势呈显著正相关,除稻田外,其他3种土地利用方式土壤N_(2)O累积排放量也与潜在硝化势呈显著正相关,以NO_(3)^(-)-N为底物的反硝化作用对N_(2)O排放的相对贡献平均大于90.00%,远高于硝化作用。【结论】南方红壤丘陵区土壤以NO_(3)^(-)-N为底物的反硝化作用主导N_(2)O排放,施用氨基氮肥可能有效减少氮肥N_(2)O排放损失,为国家执行碳中和政策提供理论依据。展开更多
In order to numerically simulate daily nitrous oxide （N2O） emission from a rice-winter wheat rotation cropping system, a process-based site model was developed （referred to as IAP-N-GAS） to track the movement and ...In order to numerically simulate daily nitrous oxide （N2O） emission from a rice-winter wheat rotation cropping system, a process-based site model was developed （referred to as IAP-N-GAS） to track the movement and transformation of several forms of nitrogen in the agro-eeosystem, which is affected by climate, soil, crop growth and management practices. The simulation of daily N2O fluxes, along with key daily environmental variables, was validated with three-year observations conducted in East China. The validation demonstrated that the model simulated well daily solar radiation, soil temperature and moisture, and also captured the dynamics and magnitude of accumulated rice aboveground biomass and mineral nitrogen in the soil. The simulated daily N2O emissions over all three years investigated were generally in good agreement with field observations. Particularly well simulated were the peak N2O emissions induced by fertilizations, rainfall events or mid-season drainages. The model simulation also represented closely the inter-annuM variation in N2O emission. These validations imply that the model has the capability to capture the general characteristics of N2O emission from a typical rice-wheat rotation agro-ecosystem. Sensitivity analyses revealed that the simulated N2O emission is most sensitive to the fertilizer application rate and the soil organic matter content, but it is much less sensitive to variations in soil pH and texture, temperature, precipitation and crop residue incorporation rate under local conditions.展开更多
Soil samples were taken from depth of 0-12cm in the virgin broad- leaved/Korean pine mixed forest in Changbai Mountain in April, 2000. 20 μL·L-1 and 200 μL·L-1 CH4 and N2O concentration were supplied for a...Soil samples were taken from depth of 0-12cm in the virgin broad- leaved/Korean pine mixed forest in Changbai Mountain in April, 2000. 20 μL·L-1 and 200 μL·L-1 CH4 and N2O concentration were supplied for analysis. Laboratory study on CH4 oxidation and N2O emission in forest soil showed that fresh soil sample could oxidize atmospheric methane and product N2O. Air-dried soil sample could not oxidize atmospheric methane, but could produCt N2O. However, it could oxidize the supplied methane quickly when its concentration was higher than 20 μL·L-1. The oxidation rate of methane was increased with its initial concentration. An addition of water to dry soil caused large pulse of N2O emissions within 2 hours. There were curvilinear correlations between N2O emission and temperature (r2=0.706, p <0.05), and between N2O emission andtwater content (r2=0.2968. p <0.05). These suggested temperature and water content were important factors controlling N2O emission. The correlation between CH4 oxidization and temperature was also found while CH4 was supplied 200 μL·L-1 (r2 =0.3573, p<0.05). Temperature was an important f8Ctor controlling CH4 oxidation. However, when 20 μL·L-1 CH4 was supplied, there was no correlation among CH4 oxidization, N2O emission, temperature and water content.展开更多
It has been previously argued that application of organic residues added in soils has a great impact on soil quality, grain productivity as well as greenhouse gas emissions. Substitution of chemical fertilizers has be...It has been previously argued that application of organic residues added in soils has a great impact on soil quality, grain productivity as well as greenhouse gas emissions. Substitution of chemical fertilizers has become a common practice in agricultural systems which consequently affect the greenhouse gas emissions from agricultural fields. To observe the effects of organic manures and crop residues amendments, five fertilizer treatments including conventional inorganic nitrogen fertilizer—NPK, cow manure, rice straw, poultry manure and sugarcane bagasse were applied in the field for two consecutive pre-monsoon rice seasons. Addition of rice straw, poultry manure and sugarcane bagasse decreased the cumulative N2O emissions by 14% and 31%, and by 1% and 7% and 5% and 3% in 2012 and 2013 respectively when compared with conventional fertilizer treatment (NPK) in both the seasons. Yield differences were not significant (p > 0.005) amongst the treatments, however, a slight increase was observed due to rice straw amendment over control. Soil organic carbon decreased by 11% - 17% under the application of organic residues which might have contributed to lower N2O emissions from the plots. Results of carbon equivalent emission (CEE) and carbon efficiency ratio (CER) indicated that incorporation of rice straw during pre-monsoon rice season had the potential to reduce the N2O emissions and yield scaled emissions of rice production at lower level than the conventional farmers’ practice of using chemical fertilizers (NPK).展开更多
We report the study on the complete three-body Coulomb explosion(CE)of N_(2)O^(q+)(q=5,6)induced by 56-keV/u Ne8+ion collision with N2O gaseous molecule.Six CE channels for N_(2)O^(5+)and seven for N_(2)O^(6+)are iden...We report the study on the complete three-body Coulomb explosion(CE)of N_(2)O^(q+)(q=5,6)induced by 56-keV/u Ne8+ion collision with N2O gaseous molecule.Six CE channels for N_(2)O^(5+)and seven for N_(2)O^(6+)are identified by measuring three ionic fragments and the charge-changed projectile in quadruple coincidence.Correspondingly the kinetic energy release(KER)and momentum correlation angle(MCA)distributions of three ionic fragments for each of the CE channels are also deduced.Numerical computation is presented to reconstruct the geometric structure of N_(2)O^(q+0prior to dissociation based on the measured KER and MCA.The N–N and N–O bond lengths and the N–N–O bond angles of N_(2)O^(q+)for each of the channels are determined.展开更多
文摘【目的】明确不同土地利用方式土壤氧化亚氮(N_(2)O)排放系数的差异并评估区域N_(2)O排放,为评估南方红壤丘陵区N_(2)O排放清单提供基础数据和参考依据。【方法】选择南方红壤丘陵区4种常见的土地利用方式(油茶林、旱地农田、稻田和松林),通过分析土壤不施肥与施氮肥时N_(2)O排放速率和排放量的差异,计算排放系数,并用^(15)N同位素标记方法探究硝化作用和反硝化作用对土壤排放N_(2)O的相对贡献。【结果】不同土地利用方式土壤理化性质差异明显,稻田全氮含量最高(2.22 g/kg),显著高于其他3种土地利用方式土壤(P<0.05,下同)。土壤不施肥时,N_(2)O排放速率在0~227.80μg/(kg·h),施氮量为200 kg N/ha时,N_(2)O排放速率在0~4213.27μg/(kg·h)。4种土地利用方式的土壤N_(2)O排放系数均随土壤孔隙含水量(WPFS)增加而增加,WPFS为75%时,稻田、旱地农田、油茶林和松林土壤N_(2)O排放系数分别为2.47%、0.39%、2.31%和0.91%。4种土地利用方式土壤N_(2)O排放系数主要受全氮含量影响,N_(2)O累积排放量均与潜在反硝化潜势呈显著正相关,除稻田外,其他3种土地利用方式土壤N_(2)O累积排放量也与潜在硝化势呈显著正相关,以NO_(3)^(-)-N为底物的反硝化作用对N_(2)O排放的相对贡献平均大于90.00%,远高于硝化作用。【结论】南方红壤丘陵区土壤以NO_(3)^(-)-N为底物的反硝化作用主导N_(2)O排放,施用氨基氮肥可能有效减少氮肥N_(2)O排放损失,为国家执行碳中和政策提供理论依据。
基金supported by the Chinese Academy of Sciences (KZCX2-YW-204, KSCX3-SW-440, KZCX1-SW-01)the National Natural Science Foundation of China (40425010, 40331014)+1 种基金the European Union (NitroEurope IP 017841)the Helmholtz Society via the Sino-German Joint Laboratory project ENTRANCE
文摘In order to numerically simulate daily nitrous oxide （N2O） emission from a rice-winter wheat rotation cropping system, a process-based site model was developed （referred to as IAP-N-GAS） to track the movement and transformation of several forms of nitrogen in the agro-eeosystem, which is affected by climate, soil, crop growth and management practices. The simulation of daily N2O fluxes, along with key daily environmental variables, was validated with three-year observations conducted in East China. The validation demonstrated that the model simulated well daily solar radiation, soil temperature and moisture, and also captured the dynamics and magnitude of accumulated rice aboveground biomass and mineral nitrogen in the soil. The simulated daily N2O emissions over all three years investigated were generally in good agreement with field observations. Particularly well simulated were the peak N2O emissions induced by fertilizations, rainfall events or mid-season drainages. The model simulation also represented closely the inter-annuM variation in N2O emission. These validations imply that the model has the capability to capture the general characteristics of N2O emission from a typical rice-wheat rotation agro-ecosystem. Sensitivity analyses revealed that the simulated N2O emission is most sensitive to the fertilizer application rate and the soil organic matter content, but it is much less sensitive to variations in soil pH and texture, temperature, precipitation and crop residue incorporation rate under local conditions.
文摘Soil samples were taken from depth of 0-12cm in the virgin broad- leaved/Korean pine mixed forest in Changbai Mountain in April, 2000. 20 μL·L-1 and 200 μL·L-1 CH4 and N2O concentration were supplied for analysis. Laboratory study on CH4 oxidation and N2O emission in forest soil showed that fresh soil sample could oxidize atmospheric methane and product N2O. Air-dried soil sample could not oxidize atmospheric methane, but could produCt N2O. However, it could oxidize the supplied methane quickly when its concentration was higher than 20 μL·L-1. The oxidation rate of methane was increased with its initial concentration. An addition of water to dry soil caused large pulse of N2O emissions within 2 hours. There were curvilinear correlations between N2O emission and temperature (r2=0.706, p <0.05), and between N2O emission andtwater content (r2=0.2968. p <0.05). These suggested temperature and water content were important factors controlling N2O emission. The correlation between CH4 oxidization and temperature was also found while CH4 was supplied 200 μL·L-1 (r2 =0.3573, p<0.05). Temperature was an important f8Ctor controlling CH4 oxidation. However, when 20 μL·L-1 CH4 was supplied, there was no correlation among CH4 oxidization, N2O emission, temperature and water content.
文摘It has been previously argued that application of organic residues added in soils has a great impact on soil quality, grain productivity as well as greenhouse gas emissions. Substitution of chemical fertilizers has become a common practice in agricultural systems which consequently affect the greenhouse gas emissions from agricultural fields. To observe the effects of organic manures and crop residues amendments, five fertilizer treatments including conventional inorganic nitrogen fertilizer—NPK, cow manure, rice straw, poultry manure and sugarcane bagasse were applied in the field for two consecutive pre-monsoon rice seasons. Addition of rice straw, poultry manure and sugarcane bagasse decreased the cumulative N2O emissions by 14% and 31%, and by 1% and 7% and 5% and 3% in 2012 and 2013 respectively when compared with conventional fertilizer treatment (NPK) in both the seasons. Yield differences were not significant (p > 0.005) amongst the treatments, however, a slight increase was observed due to rice straw amendment over control. Soil organic carbon decreased by 11% - 17% under the application of organic residues which might have contributed to lower N2O emissions from the plots. Results of carbon equivalent emission (CEE) and carbon efficiency ratio (CER) indicated that incorporation of rice straw during pre-monsoon rice season had the potential to reduce the N2O emissions and yield scaled emissions of rice production at lower level than the conventional farmers’ practice of using chemical fertilizers (NPK).
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2017YFA0402300 and 2017YFA0303501)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB34000000)。
文摘We report the study on the complete three-body Coulomb explosion(CE)of N_(2)O^(q+)(q=5,6)induced by 56-keV/u Ne8+ion collision with N2O gaseous molecule.Six CE channels for N_(2)O^(5+)and seven for N_(2)O^(6+)are identified by measuring three ionic fragments and the charge-changed projectile in quadruple coincidence.Correspondingly the kinetic energy release(KER)and momentum correlation angle(MCA)distributions of three ionic fragments for each of the CE channels are also deduced.Numerical computation is presented to reconstruct the geometric structure of N_(2)O^(q+0prior to dissociation based on the measured KER and MCA.The N–N and N–O bond lengths and the N–N–O bond angles of N_(2)O^(q+)for each of the channels are determined.
