This paper describes data of nitrous oxides (NO) emissions from open-field and greenhouse systems... more This paper describes data of nitrous oxides (NO) emissions from open-field and greenhouse systems in Chinese vegetable production. The data also describes the potential soil and management factors to identify the effective measures to mitigate NO emissions. The data were collected from 21 peer-reviewed papers, covering 153 NO emission field measurements as affected by fertilizer nitrogen (N) management. This data were subjected to meta-analysis for a comprehensive assessment on NO emission and applied N based emission factor in Chinese vegetable production.
Fall application of anhydrous ammonia in Manitoba is common but its impact on nitrous oxide (NO) ... more Fall application of anhydrous ammonia in Manitoba is common but its impact on nitrous oxide (NO) emissions is not well known. A 2-yr study compared application before freeze-up in late fall to spring pre-plant application of anhydrous ammonia on nitrous oxide (NO) emissions from a clay soil in the Red River Valley, Manitoba. Spring wheat ( L.) and corn ( L.) were grown on two 4-ha fields in 2011 and 2012, respectively. Field-scale flux of NO was measured using a flux-gradient micrometeorological approach. Late fall treatment did not induce NO emissions soon after application or in winter likely because soil was frozen. Application time did alter the temporal pattern of emissions with late fall and spring pre-plant applications significantly increasing median daily NO flux at spring thaw and early crop growing season, respectively. The majority of emissions occurred in early growing season resulting in cumulative emissions for the crop year being numerically 33% less for late fall than spring pre-plant application. Poor yield in the first year with late fall treatment occurred because of weed and volunteer growth with delayed planting. Results show late fall application of anhydrous ammonia before freeze-up increased NO emissions at thaw and decreased emissions for the early growing season compared to spring pre-plant application. However, improved nitrogen availability of late fall application to crops the following year is required when planting is delayed because of excessive moisture in spring.
The solid behavior in a turbulent fluidized bed was studied by combination of experimental measur... more The solid behavior in a turbulent fluidized bed was studied by combination of experimental measurements and computational fluid dynamics (CFD) simulations. Solid fractions were measured by optical fiber probe under three different superficial gas velocities and three different static bed heights at different axial levels. The experimental results showed that the lateral distribution of solid fraction is core-annulus and the operating conditions can influence the shape of the axial bed void profiles. In the CFD simulations, an Eulerian–Eulerian two-fluid model that incorporates the kinetic theory of granular flow was used to describe the gas–solid two-phase flow in a turbulent fluidized bed. A modified drag model was proposed using a scaling factor to reduce the universal drag laws, which accounts for the effect of particle clustering. The drag model can predict the coexisting regions, the bottom dense, bubbling region and the dilute, dispersed flow region observed in experiments. No significant difference was observed between results after application of laminar and turbulence model. The simulated axial bed void and radial solid fraction fit well with experimental data. The transient local solid fraction and the particle velocity were also investigated.The solid behavior in a turbulent fluidized bed was studied by combination of experimental measurements and computational fluid dynamics (CFD) simulations. A modified drag model was proposed using a scaling factor to reduce the universal drag laws, which accounts for the effect of particle clustering.► Solid behavior in a turbulent fluidized bed was investigated. ► Solid fractions were measured by an optical fiber probe. ► Effects of superficial gas velocities and static bed heights are investigated. ► A modified drag model was proposed accounting for the effect of particle clustering.
... Xiaopeng Gao, Chunqin Zou,* Lijun Wang, and Fusuo Zhang Key Laboratory of PlantSoil Interact... more ... Xiaopeng Gao, Chunqin Zou,* Lijun Wang, and Fusuo Zhang Key Laboratory of PlantSoil Interactions, MOE, Key Laboratory of Plant Nutrition, MOA, Department of Plant Nutrition, China Agricultural University, Beijing, PR China ABSTRACT ...
DNDC performed well in capturing the impact of cropping intensity on nitrous oxide emissions at t... more DNDC performed well in capturing the impact of cropping intensity on nitrous oxide emissions at two locations in eastern (humid) and western (sub-humid) Canada. The model also was able to discern the proportional seasonal contribution of N2O towards the annual flux for both locations. Differences in the magnitude of measured N2O emissions between replicate plots highlighted the challenges in validating process-based models for specific treatment effects. The cascade water model framework included in DNDC performed well in regulating biomass production and N2O emissions from nitrification, however, challenges exist in accurately simulating N2O emissions from the denitrification process when measured soil water content was at or above field capacity for extended durations. Spring burst emission events in most cases were captured by DNDC however the timing and magnitude of emissions were sometimes inaccurate at the Elora site. A more robust mechanism describing thermal insulation of sn...
ABSTRACT Information regarding the greenhouse gas (GHG) emissions resulting from the application ... more ABSTRACT Information regarding the greenhouse gas (GHG) emissions resulting from the application of pig slurry to forage in western Canada is limited. This study examined the effects of addition of pig slurry and soil water content with landscape position on nitrous oxide (N2O) and methane (CH4) emissions from forage legumes [sainfoin (Onobrychis viciifolia) and alfalfa (Medicago sativa)] on a sandy loam soil in Brandon, Manitoba, over two growing seasons. Pig slurry was surface applied with a rolling aerator-type tine at a rate of 35 000 L ha(-1) and 38 000 L ha(-1), providing 62-15-50 and 205-45-86, actual N-P-K kg ha(-1), in 2006 and 2007, respectively. Emissions were measured on and between surface bands of the slurry applied to soil. Soil concentrations of NH4+ -N and NO3- -N, moisture, and temperature were also monitored. In both years, slurry application increased growing season cumulative N2O emissions. Net increase in cumulative N2O-N emissions with slurry treatment ranged from 0.04 to 0.05% of total N ha(-1)Z applied in 2006 but from 0.7 to 0.9% in 2007. The coherence of rapidly increasing N2O emissions following slurry application with decreasing soil NH4+ and increasing NO3- concentration, in combination with the fact that emissions continued even when soil NH4+ concentrations were undetectable, suggest nitrification and denitrification were sources of N2O. Emissions of CH4 were generally slightly negative and unaffected by addition of slurry. Higher soil water content at lower landscape position did not affect emissions of CH4 but did increase those of N2O in 2007. The current study was conducted at one field location. Examination of slurry additions to additional sites is required for reliable estimation of N2O emissions from slurry applied to perennial legume forages in prairie Canada.
Zinc (Zn) deficiency is a widely occurring constraint for rice production and for human nutrition... more Zinc (Zn) deficiency is a widely occurring constraint for rice production and for human nutrition. Scarcity of water is leading to a shift from flooded to aerobic rice production, which can have an impact on Zn deficiency in rice. Zinc bioavailability is a function of both soil and plant factors that can be altered by water management, particularly in relation
This paper describes data of nitrous oxides (NO) emissions from open-field and greenhouse systems... more This paper describes data of nitrous oxides (NO) emissions from open-field and greenhouse systems in Chinese vegetable production. The data also describes the potential soil and management factors to identify the effective measures to mitigate NO emissions. The data were collected from 21 peer-reviewed papers, covering 153 NO emission field measurements as affected by fertilizer nitrogen (N) management. This data were subjected to meta-analysis for a comprehensive assessment on NO emission and applied N based emission factor in Chinese vegetable production.
Fall application of anhydrous ammonia in Manitoba is common but its impact on nitrous oxide (NO) ... more Fall application of anhydrous ammonia in Manitoba is common but its impact on nitrous oxide (NO) emissions is not well known. A 2-yr study compared application before freeze-up in late fall to spring pre-plant application of anhydrous ammonia on nitrous oxide (NO) emissions from a clay soil in the Red River Valley, Manitoba. Spring wheat ( L.) and corn ( L.) were grown on two 4-ha fields in 2011 and 2012, respectively. Field-scale flux of NO was measured using a flux-gradient micrometeorological approach. Late fall treatment did not induce NO emissions soon after application or in winter likely because soil was frozen. Application time did alter the temporal pattern of emissions with late fall and spring pre-plant applications significantly increasing median daily NO flux at spring thaw and early crop growing season, respectively. The majority of emissions occurred in early growing season resulting in cumulative emissions for the crop year being numerically 33% less for late fall than spring pre-plant application. Poor yield in the first year with late fall treatment occurred because of weed and volunteer growth with delayed planting. Results show late fall application of anhydrous ammonia before freeze-up increased NO emissions at thaw and decreased emissions for the early growing season compared to spring pre-plant application. However, improved nitrogen availability of late fall application to crops the following year is required when planting is delayed because of excessive moisture in spring.
The solid behavior in a turbulent fluidized bed was studied by combination of experimental measur... more The solid behavior in a turbulent fluidized bed was studied by combination of experimental measurements and computational fluid dynamics (CFD) simulations. Solid fractions were measured by optical fiber probe under three different superficial gas velocities and three different static bed heights at different axial levels. The experimental results showed that the lateral distribution of solid fraction is core-annulus and the operating conditions can influence the shape of the axial bed void profiles. In the CFD simulations, an Eulerian–Eulerian two-fluid model that incorporates the kinetic theory of granular flow was used to describe the gas–solid two-phase flow in a turbulent fluidized bed. A modified drag model was proposed using a scaling factor to reduce the universal drag laws, which accounts for the effect of particle clustering. The drag model can predict the coexisting regions, the bottom dense, bubbling region and the dilute, dispersed flow region observed in experiments. No significant difference was observed between results after application of laminar and turbulence model. The simulated axial bed void and radial solid fraction fit well with experimental data. The transient local solid fraction and the particle velocity were also investigated.The solid behavior in a turbulent fluidized bed was studied by combination of experimental measurements and computational fluid dynamics (CFD) simulations. A modified drag model was proposed using a scaling factor to reduce the universal drag laws, which accounts for the effect of particle clustering.► Solid behavior in a turbulent fluidized bed was investigated. ► Solid fractions were measured by an optical fiber probe. ► Effects of superficial gas velocities and static bed heights are investigated. ► A modified drag model was proposed accounting for the effect of particle clustering.
... Xiaopeng Gao, Chunqin Zou,* Lijun Wang, and Fusuo Zhang Key Laboratory of PlantSoil Interact... more ... Xiaopeng Gao, Chunqin Zou,* Lijun Wang, and Fusuo Zhang Key Laboratory of PlantSoil Interactions, MOE, Key Laboratory of Plant Nutrition, MOA, Department of Plant Nutrition, China Agricultural University, Beijing, PR China ABSTRACT ...
DNDC performed well in capturing the impact of cropping intensity on nitrous oxide emissions at t... more DNDC performed well in capturing the impact of cropping intensity on nitrous oxide emissions at two locations in eastern (humid) and western (sub-humid) Canada. The model also was able to discern the proportional seasonal contribution of N2O towards the annual flux for both locations. Differences in the magnitude of measured N2O emissions between replicate plots highlighted the challenges in validating process-based models for specific treatment effects. The cascade water model framework included in DNDC performed well in regulating biomass production and N2O emissions from nitrification, however, challenges exist in accurately simulating N2O emissions from the denitrification process when measured soil water content was at or above field capacity for extended durations. Spring burst emission events in most cases were captured by DNDC however the timing and magnitude of emissions were sometimes inaccurate at the Elora site. A more robust mechanism describing thermal insulation of sn...
ABSTRACT Information regarding the greenhouse gas (GHG) emissions resulting from the application ... more ABSTRACT Information regarding the greenhouse gas (GHG) emissions resulting from the application of pig slurry to forage in western Canada is limited. This study examined the effects of addition of pig slurry and soil water content with landscape position on nitrous oxide (N2O) and methane (CH4) emissions from forage legumes [sainfoin (Onobrychis viciifolia) and alfalfa (Medicago sativa)] on a sandy loam soil in Brandon, Manitoba, over two growing seasons. Pig slurry was surface applied with a rolling aerator-type tine at a rate of 35 000 L ha(-1) and 38 000 L ha(-1), providing 62-15-50 and 205-45-86, actual N-P-K kg ha(-1), in 2006 and 2007, respectively. Emissions were measured on and between surface bands of the slurry applied to soil. Soil concentrations of NH4+ -N and NO3- -N, moisture, and temperature were also monitored. In both years, slurry application increased growing season cumulative N2O emissions. Net increase in cumulative N2O-N emissions with slurry treatment ranged from 0.04 to 0.05% of total N ha(-1)Z applied in 2006 but from 0.7 to 0.9% in 2007. The coherence of rapidly increasing N2O emissions following slurry application with decreasing soil NH4+ and increasing NO3- concentration, in combination with the fact that emissions continued even when soil NH4+ concentrations were undetectable, suggest nitrification and denitrification were sources of N2O. Emissions of CH4 were generally slightly negative and unaffected by addition of slurry. Higher soil water content at lower landscape position did not affect emissions of CH4 but did increase those of N2O in 2007. The current study was conducted at one field location. Examination of slurry additions to additional sites is required for reliable estimation of N2O emissions from slurry applied to perennial legume forages in prairie Canada.
Zinc (Zn) deficiency is a widely occurring constraint for rice production and for human nutrition... more Zinc (Zn) deficiency is a widely occurring constraint for rice production and for human nutrition. Scarcity of water is leading to a shift from flooded to aerobic rice production, which can have an impact on Zn deficiency in rice. Zinc bioavailability is a function of both soil and plant factors that can be altered by water management, particularly in relation
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