Key Factors, Soil Nitrogen Processes, and Nitrite Accumulation Affecting Nitrous Oxide Emissions

Cai, Zejiang; Gao, Suduan; Hendratna, Aileen; Duan, Yinghua; Xu, Minggang; Hanson, Bradley D.

doi:10.2136/sssaj2016.03.0089

Cited by 31 publications

(25 citation statements)

References 42 publications

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“…Several studies have reported WFPS as the main regulating factor of soil N 2 O emissions (Dobbie and Smith, 2003; Alvarez et al, 2012; Cai et al, 2016). The observation that soil temperature was a significant factor when considering the whole year, but not when considering only the growing season, suggests that there might be a “threshold” effect of soil temperature as proposed by Cosentino et al, (2013).…”

Section: Discussionmentioning

confidence: 99%

Gross, Background, and Net Anthropogenic Soil Nitrous Oxide Emissions from Soybean, Corn, and Wheat Croplands

2019

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Agricultural soils are the largest single source of N2O emissions globally. However, soils left uncultivated would still release N2O. Distinguishing anthropogenic from natural emissions (i.e., background emissions) in crops is important if we want to assess the net effect of human activity. This study aimed to characterize N2O emissions from croplands and unmanaged grasslands to estimate the net anthropogenic emissions and to gain a better insight into their main drivers. We established a replicated manipulative field experiment in the Pampas Region of Argentina to quantify soil N2O emissions from corn (Zea mays L.), wheat (Triticum aestivum L.), and soybean [Glycine max (L.) Merr.] crops, and from adjacent unmanaged grassland plots for 1 yr. We also analyzed the main controls of N2O emissions and the correlation between the normalized difference vegetation index (NDVI) and N2O fluxes. Background emissions represented between 21 and 32% of total emissions from croplands, depending on crop type. No differences were detected in N2O emissions between total and background during winter and peak crop growing season. NDVI showed a significant correlation with N2O fluxes which was positive in grasslands and negative in growing season of soybean crops. Our results showed that N2O emissions from croplands were higher than background emissions, but also that background represented an important fraction of cropland emissions. Higher emissions in croplands occurred during pre‐seeding, after harvest, and after N fertilization in fertilized crops. In addition, our study informs about N2O emissions from crops and unmanaged systems in South America where field data are very scarce. Core Ideas We measured soil N2O emissions in South America where field data are very scarce. Nonanthropogenic fluxes represented 21 to 32% of crop N2O emissions. NDVI, a plant productivity index, improved seasonal estimation of N2O flux.

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Section: Discussionmentioning

confidence: 99%

Gross, Background, and Net Anthropogenic Soil Nitrous Oxide Emissions from Soybean, Corn, and Wheat Croplands

2019

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“…Many studies have observed the increased N 2 O emissions as soil moisture or WFPS increased Dobbie et al [5], Schindlbacher et al [7], Trost et al [6], and Pimentel et al [8]. This relationship was further examined under well controlled conditions by Cai et al [3] who found two distinctly different linear correlations between N 2 O emission and soil nitrite (a precursor for N 2 O) concentration with a much deeper slope for soil moisture above water holding capacity than that below. In the current study, significantly higher soil water content in DI than that from SDI in soil depth above 40 cm was determined ( Fig.…”

Section: Mitigation Of N 2 O Emission Through Irrigation and Fertimentioning

confidence: 95%

“…An integrated system (drip irrigation, reduced tillage, and fertigation) has shown to significantly reduce N 2 O emissions by >70% in comparison with the conventional (furrow irrigation and sidedress fertilizer injection) [10]. Under DI, fertilizer types also affect surface emissions of N 2 O in an almond orchard, which were estimated as: high frequency irrigation or HF with urea and ammonium nitrate (UAN) > standard (4× year -1 ) UAN > HF NO 3 - [22]. They also found that N 2 O production was highest at 10-15 cm depth and reduced below 20 cm depth, which agrees with our observations (Fig.…”

Section: Mitigation Of N 2 O Emission Through Irrigation and Fertimentioning

confidence: 99%

“…Nitrous oxide is produced primarily via microbial nitrification and denitrification processes. With increased soil water content, denitrification can become more significant and that led to much higher N 2 O emissions [2], [3]. A number of studies have shown that N 2 O emissions were related positively to irrigation or irrigation amount [4] and increased by increasing or higher water-filled pore space (WFPS) [5], Trost et al [6].…”

Section: Introductionmentioning

confidence: 99%

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Subsurface Drip Irrigation Reduced Nitrous Oxide Emissions in a Pomegranate Orchard

Gao¹,

Hendratna²,

Cai³

et al. 2019

IJESD

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Soil fertilization is one of the major sources for nitrous oxide (N 2 O) emissions and soil moisture is among the most important factors affecting its production. Thus, one of the important mitigation strategies in semiarid or arid regions is through irrigation and/or fertigation management. The objective of this research was to evaluate the effects of different drip irrigation methods and N application levels on N 2 O emissions. Nitrous oxide emission flux and N 2 O concentration in soil profile were measured in a pomegranate field for two growing seasons under two irrigation systems [subsurface drip irrigation (SDI) at ~0.5 m depth and traditional surface drip irrigation (DI)], and three N application rates (50%, 100%, and 150% of current practice rate). Both years' data showed that N 2 O emissions has a high and positive correlation with N fertilization events and application levels. Nitrous oxide emissions from DI at 100% and 150% N levels were over an order of magnitude higher compared to those from SDI based on the data of the first year. Data from the second year confirmed the first year's findings of high emissions from DI. A positive linear correlation between the N 2 O emission flux and N 2 O concentration in soil-gas phase was identified that supported emission data. This research demonstrated that although N fertilization is a major cause for N 2 O emissions, subsurface drip irrigation/fertigation can lead to a significant emission reduction in addition to other benefits, such as increased water and nutrient use efficiencies, and reduced weed pressure.Index Terms-Chemical nitrogen fertilizer, greenhouse gas emission, high-frequency drip irrigation.

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“…Parts et al (2013) detected several changes in silver birch absorptive root morphology as well as in the ectomycorrhizal colonization pattern, reflecting the adaptation mechanism of this tree species at elevated air humidity conditions. Studies have shown that increase in soil water content and temperature leads to increase in N 2 O emission and to higher soil respiration rates as a positive feedback response of increased microbial metabolism (Cai et al, 2016; Oertel et al, 2016). In case of increased air humidity both the soil properties and plant traits are changed but the knowledge about the impact of increased air humidity on soil microbial community structures and functioning at potentially affected regions is still missing.…”

Section: Introductionmentioning

confidence: 99%

Elevated Air Humidity Changes Soil Bacterial Community Structure in the Silver Birch Stand

et al. 2017

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Soil microbes play a fundamental role in forest ecosystems and respond rapidly to changes in the environment. Simultaneously with the temperature increase the climate change scenarios also predict an intensified hydrological cycle for the Baltic Sea runoff region. The aim of this study was to assess the effect of elevated air humidity on the top soil microbial community structure of a silver birch (Betula pendula Roth.) stand by using a free air humidity manipulation facility (FAHM). The bacterial community structures of bulk soil and birch rhizosphere were analyzed using high-throughput sequencing of bacteria-specific16S rRNA gene fragments and quantification of denitrification related genes. The increased air humidity altered both bulk soil and rhizosphere bacterial community structures, and changes in the bacterial communities initiated by elevated air humidity were related to modified soil abiotic and biotic variables. Network analysis revealed that variation in soil bacterial community structural units is explained by altered abiotic conditions such as increased pH value in bulk soil, while in rhizosphere the change in absorptive root morphology had a higher effect. Among root morphological traits, the absorptive root diameter was strongest related to the bacterial community structure. The changes in bacterial community structures under elevated air humidity are associated with shifts in C, N, and P turnover as well as mineral weathering processes in soil. Increased air humidity decreased the nir and nosZ gene abundance in the rhizosphere bacterial community. The potential contribution of the denitrification to the N2O emission was not affected by the elevated air humidity in birch stand soil. In addition, the study revealed a strong link between the bacterial community structure, abundance of denitrification related genes, and birch absorptive root morphology in the ecosystem system adaptation to elevated air humidity.

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Key Factors, Soil Nitrogen Processes, and Nitrite Accumulation Affecting Nitrous Oxide Emissions

Cited by 31 publications

References 42 publications

Gross, Background, and Net Anthropogenic Soil Nitrous Oxide Emissions from Soybean, Corn, and Wheat Croplands

Gross, Background, and Net Anthropogenic Soil Nitrous Oxide Emissions from Soybean, Corn, and Wheat Croplands

Subsurface Drip Irrigation Reduced Nitrous Oxide Emissions in a Pomegranate Orchard

Elevated Air Humidity Changes Soil Bacterial Community Structure in the Silver Birch Stand

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