Xiaopeng Gao - Academia.edu (original) (raw)
BMP Fact Sheets by Xiaopeng Gao
Consider 4Rs (rate, source, placement, timing) practices to optimize crop N use Select lowest... more Consider 4Rs (rate, source, placement, timing) practices to optimize crop N use Select lowest rate of N to optimize yield based on other 3 Rs Consider residual soil nitrate, mineralization, yield goal and N loss potential of field in determining N rate Use split applications of urea or fertigation rather than single application of urea Use controlled-release urea (ESN) instead of granular urea Use stabilized granular urea or nitrification inhibitors Band granular urea and ESN rather than broadcast incorporation Avoid excess moisture conditions after application of N fertilizer
Papers by Xiaopeng Gao
Data in brief, 2018
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.
Journal of Environment Quality, 2016
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 Proceedings of the International Plant Nutrition Colloquium Xvi, Apr 7, 2009
Powder Technology, Sep 1, 2012
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.
Plant and Soil, 2007
Plant Zn uptake from low Zn soils can be increased by Zn-mobilizing chemical rhizosphere processe... more Plant Zn uptake from low Zn soils can be increased by Zn-mobilizing chemical rhizosphere processes. We studied whether inoculation with arbuscular mycorrhizal fungi (AMF) can be an additional or an alternative strategy. We determined the effect of AMF inoculation on growth performance and Zn uptake by rice genotypes varying in Zn uptake when nonmycorrhizal. A pot experiment was conducted with six aerobic rice genotypes inoculated with Glomus mosseae or G. etunicatum or without AMF on a low Zn soil. Plant growth, Zn uptake and mycorrhizal responsiveness were determined. AMFinoculated plants produced more biomass and took up more Zn than nonmycorrhizal controls. Mycorrhizal inoculation, however, significantly increased Zn uptake only in genotypes that had a low Zn uptake in the nonmycorrhizal condition. We conclude that genotypes that are less efficient in Zn uptake when nonmycorrhizal are more responsive to AMF inoculation. We provide examples from literature allowing generalization of this conclusion on a trade off between mycorrhizal responsiveness and nutrient uptake efficiency.
Journal of Plant Nutrition, 2004
... 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 ...
Field studies were conducted since 2002 at five locations across the Canadian prairies to study t... more Field studies were conducted since 2002 at five locations across the Canadian prairies to study the long-term effects of P fertilizer application rate and Cd content on seed Cd concentration of durum wheat (Triticum turgidum L.) and flax (Linum usitatissimum L.). Cadmium concentration was higher in durum wheat than flax and varied with location. Cadmium concentration in the seed of both crops increased with application of P fertilizer even when the fertilizer contained only trace concentrations of Cd, indicating that P fertilization directly influenced Cd concentration of crops apart from the effect of Cd addition. Seed Cd concentration was higher when the fertilizer contained greater Cd concentrations, particularly when rate of fertilizer application was also high. Cadmium concentration in crops was directly proportional to the total amount of Cd applied over time, but the effect of fertilizer application varied with soil characteristics. Highest availability of Cd added in P fertilizer was on light-textured or acidic soil, while availability of applied Cd was lower on heavier-textured or higher pH soils. Therefore, soil characteristics that affect phytoavailability must be taken into account when assessing the risk of transfer of Cd into the food chain from P fertilization.
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...
Applied and Environmental Soil Science, 2012
Field experiments were conducted at two locations in Manitoba, Canada, to determine the effect of... more Field experiments were conducted at two locations in Manitoba, Canada, to determine the effect of crop rotation, phosphorus (P) fertilization and tillage on grain yield and grain concentrations of Cd and Zn in durum wheat (Triticum durum L.). Compared to conventional tillage (CT), reduced tillage (RT) management decreased grain Cd and increased grain yield and grain Zn in half of the site-years. The type of preceding crops of spring wheat-flax or canola-flax had little influence. Rate and timing of P application had little effect on grain Cd, but increasing P rate tended to decrease grain Zn. No interactive effect was detected among tested factors. Grain Zn was not related to grain Cd, but positively to other nutrients such as Fe, Mn, P, Ca, K, and Mg. Both grain Zn and Fe correlated positively with grain protein content, suggesting protein may represent a sink for micronutrients. The study suggested that the tillage management may have beneficial effects on both grain yield and quality. Phosphorus fertilizer can remain available for subsequent crops and high annual inputs in the crop sequence may decrease crop grain Zn. Understanding the environment is important in determining the impact of agricultural management on agronomic and nutrient traits.
Development and Uses of Biofortified Agricultural Products, 2008
Canadian Journal of Soil Science, 2014
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.
Development and Uses of Biofortified Agricultural Products, 2008
Agronomy for Sustainable Development, 2011
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
Consider 4Rs (rate, source, placement, timing) practices to optimize crop N use Select lowest... more Consider 4Rs (rate, source, placement, timing) practices to optimize crop N use Select lowest rate of N to optimize yield based on other 3 Rs Consider residual soil nitrate, mineralization, yield goal and N loss potential of field in determining N rate Use split applications of urea or fertigation rather than single application of urea Use controlled-release urea (ESN) instead of granular urea Use stabilized granular urea or nitrification inhibitors Band granular urea and ESN rather than broadcast incorporation Avoid excess moisture conditions after application of N fertilizer
Data in brief, 2018
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.
Journal of Environment Quality, 2016
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 Proceedings of the International Plant Nutrition Colloquium Xvi, Apr 7, 2009
Powder Technology, Sep 1, 2012
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.
Plant and Soil, 2007
Plant Zn uptake from low Zn soils can be increased by Zn-mobilizing chemical rhizosphere processe... more Plant Zn uptake from low Zn soils can be increased by Zn-mobilizing chemical rhizosphere processes. We studied whether inoculation with arbuscular mycorrhizal fungi (AMF) can be an additional or an alternative strategy. We determined the effect of AMF inoculation on growth performance and Zn uptake by rice genotypes varying in Zn uptake when nonmycorrhizal. A pot experiment was conducted with six aerobic rice genotypes inoculated with Glomus mosseae or G. etunicatum or without AMF on a low Zn soil. Plant growth, Zn uptake and mycorrhizal responsiveness were determined. AMFinoculated plants produced more biomass and took up more Zn than nonmycorrhizal controls. Mycorrhizal inoculation, however, significantly increased Zn uptake only in genotypes that had a low Zn uptake in the nonmycorrhizal condition. We conclude that genotypes that are less efficient in Zn uptake when nonmycorrhizal are more responsive to AMF inoculation. We provide examples from literature allowing generalization of this conclusion on a trade off between mycorrhizal responsiveness and nutrient uptake efficiency.
Journal of Plant Nutrition, 2004
... 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 ...
Field studies were conducted since 2002 at five locations across the Canadian prairies to study t... more Field studies were conducted since 2002 at five locations across the Canadian prairies to study the long-term effects of P fertilizer application rate and Cd content on seed Cd concentration of durum wheat (Triticum turgidum L.) and flax (Linum usitatissimum L.). Cadmium concentration was higher in durum wheat than flax and varied with location. Cadmium concentration in the seed of both crops increased with application of P fertilizer even when the fertilizer contained only trace concentrations of Cd, indicating that P fertilization directly influenced Cd concentration of crops apart from the effect of Cd addition. Seed Cd concentration was higher when the fertilizer contained greater Cd concentrations, particularly when rate of fertilizer application was also high. Cadmium concentration in crops was directly proportional to the total amount of Cd applied over time, but the effect of fertilizer application varied with soil characteristics. Highest availability of Cd added in P fertilizer was on light-textured or acidic soil, while availability of applied Cd was lower on heavier-textured or higher pH soils. Therefore, soil characteristics that affect phytoavailability must be taken into account when assessing the risk of transfer of Cd into the food chain from P fertilization.
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...
Applied and Environmental Soil Science, 2012
Field experiments were conducted at two locations in Manitoba, Canada, to determine the effect of... more Field experiments were conducted at two locations in Manitoba, Canada, to determine the effect of crop rotation, phosphorus (P) fertilization and tillage on grain yield and grain concentrations of Cd and Zn in durum wheat (Triticum durum L.). Compared to conventional tillage (CT), reduced tillage (RT) management decreased grain Cd and increased grain yield and grain Zn in half of the site-years. The type of preceding crops of spring wheat-flax or canola-flax had little influence. Rate and timing of P application had little effect on grain Cd, but increasing P rate tended to decrease grain Zn. No interactive effect was detected among tested factors. Grain Zn was not related to grain Cd, but positively to other nutrients such as Fe, Mn, P, Ca, K, and Mg. Both grain Zn and Fe correlated positively with grain protein content, suggesting protein may represent a sink for micronutrients. The study suggested that the tillage management may have beneficial effects on both grain yield and quality. Phosphorus fertilizer can remain available for subsequent crops and high annual inputs in the crop sequence may decrease crop grain Zn. Understanding the environment is important in determining the impact of agricultural management on agronomic and nutrient traits.
Development and Uses of Biofortified Agricultural Products, 2008
Canadian Journal of Soil Science, 2014
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.
Development and Uses of Biofortified Agricultural Products, 2008
Agronomy for Sustainable Development, 2011
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
Agronomy Journal, 2015
ABSTRACT The effects of band placement of enhanced efficiency fertilizers (EEF) on nitrous oxide ... more ABSTRACT The effects of band placement of enhanced efficiency fertilizers (EEF) on nitrous oxide (N2O) emissions are uncertain. Placement and EEF on N2O emissions from spring wheat (Triticum aestivum L.) at two locations in Manitoba, in 2011 and 2012 were examined. Treatments were a no N control and 80 kg N ha-1 at planting of ve combinations of placement and granular N source: Broadcast-incorporated urea (UreaI) and, subsurface side-banded urea (UreaS; each row side-banded), midrow-banded urea (UreaM; placement between every other set of rows), midrow-banded environmentally smart nitrogen (ESN, Agrium, Inc.) (ESNM), and midrow-banded SuperU (Koch Industries Inc.) (SuperUM). Planting in 2011 was delayed 40 d compared to 2012. Planting coincided with higher soil temperature and moisture resulting in threeto sevenfold more growing season N2O emissions (SN2O) in 2011 than 2012. In 2011, SuperUM and ESNM reduced ∑N2O, emission factor (EF) scaled by N-applied EF, and yield-scaled N2O emission intensity (EI) by 47, 67, and 55%, respectively, compared with UreaI. In 2011, increasing placement concentration of N in order broadcast-incorporation, side-banding, and midrow-banding tended to decrease ∑N2O, EF, and EI of granular urea, but not statistically significant. The ∑N2O and nitrate exposure (NE), were significantly correlated over the siteyears, indicating N availability from treatments in part determined emissions. Grain yield and crop N uptake were unaffected by sources and placement. These results suggest for early season wet and warm conditions, EEF N sources can reduce emissions compared with granular urea. Further studies are required to clarify placement effects on N2O emissions. © 2015 by the American Society of Agronomy, 5585 Guilford Road, Madison, WI 53711. All rights reserved.