Hotspots of soil N2O emission enhanced through water absorption by plant residue

Nature Geoscience, Год журнала: 2017, Номер 10(7), С. 496 - 500

Опубликована: Июнь 5, 2017

Язык: Английский

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Quantifying nitrous oxide production rates from nitrification and denitrification under various moisture conditions in agricultural soils: Laboratory study and literature synthesis

Frontiers in Microbiology, Год журнала: 2023, Номер 13

Опубликована: Янв. 12, 2023

Biogenic nitrous oxide (N2O) from nitrification and denitrification in agricultural soils is a major source of N2O the atmosphere, its flux changes significantly with soil moisture condition. However, quantitative relationship between production different pathways (i.e., vs. denitrification) content remains elusive, limiting our ability predicting future emissions under changing environment. This study quantified rates various conditions using laboratory incubation combined literature synthesis. 15N labeling approach was used to differentiate eight contents ranging 40 120% water-filled pore space (WFPS) study, while 80 groups data 17 studies across global were collected Results showed that as increased, first increased then decreased, peak occurring 95% WFPS. By contrast, dominant pathway switched 60 70% Furthermore, synthetic elucidated driver controlling relative contributions production, NH4 + NO3 - concentrations mainly determined each pathway. The treatments broad narrow gradient required capture comprehensive response rate change, essential for accurately emission climate change scenarios.

Язык: Английский

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Greenhouse gas emissions from natural ecosystems and agricultural lands in sub-Saharan Africa: synthesis of available data and suggestions for further research

Biogeosciences, Год журнала: 2016, Номер 13(16), С. 4789 - 4809

Опубликована: Авг. 29, 2016

Abstract. This paper summarizes currently available data on greenhouse gas (GHG) emissions from African natural ecosystems and agricultural lands. The are used to synthesize current understanding of the drivers change in GHG emissions, outline knowledge gaps, suggest future directions strategies for emission research. were collected 75 studies conducted 22 countries (n = 244) sub-Saharan Africa (SSA). Carbon dioxide (CO2) by far largest contributor global warming potential (GWP) SSA terrestrial systems. CO2 ranged 3.3 57.0 Mg ha−1 yr−1, methane (CH4) −4.8 3.5 kg yr−1 (−0.16 0.12 equivalent (eq.) yr−1), nitrous oxide (N2O) −0.1 13.7 (−0.03 4.1 eq. yr−1). Soil physical chemical properties, rewetting, vegetation type, forest management, land-use changes all found be important factors affecting soil In aquatic systems, was total ranging 5.7 232.0 followed −26.3 2741.9 CH4 (−0.89 93.2 yr−1) 0.2 N2O (0.06 1.0 Rates systems affected location, hydrological characteristics, water quality. croplands, also dominated CO2, 1.7 141.2 with −1.3 66.7 (−0.04 2.3 0.05 112.0 (0.015 33.4 (EFs) 0.01 %. Incorporation crop residues or manure inorganic fertilizers invariably resulted significant but results inconsistent as magnitude direction differed gas. vegetable gardens 73.3 132.0 53.4 177.6 (15.9 52.9 EFs 3 4 agroforestry 38.6 26.7 8.0 respectively. Improving fallow nitrogen (N)-fixing trees led increased compared conventional croplands. type quality plant residue is an control how affected. Throughout lands, slowly N inputs below 150 exponentially application rates up 300 yr−1. lowest yield-scaled reported between 100 ha−1. Overall, lands 56.9 ± 12.7 × 109 contributing 76.3 23.7 %, Additional measurements urgently required reduce uncertainty annual different land uses identify major mitigation options low-emission development. A common strategy addressing this gap may include identifying priorities acquisition, utilizing appropriate technologies, involving international networks collaboration.

Язык: Английский

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Machine learning improves predictions of agricultural nitrous oxide (N₂O) emissions from intensively managed cropping systems

Environmental Research Letters, Год журнала: 2020, Номер 16(2), С. 024004 - 024004

Опубликована: Дек. 12, 2020

The potent greenhouse gas nitrous oxide (N2O) is accumulating in the atmosphere at unprecedented rates largely due to agricultural intensification, and cultivated soils contribute ∼60% of flux. Empirical models N2O fluxes for intensively managed cropping systems are confounded by highly variable limited geographic coverage; process-based biogeochemical rarely able predict daily monthly emissions with >20% accuracy even site-specific calibration. Here we show promise machine learning (ML) significantly improve field-level flux predictions, especially when coupled a model simulate unmeasured soil parameters. We used sub-daily data from six years automated chambers installed continuous corn rotation site upper US Midwest (∼3000 observations), supplemented weekly biweekly manual chamber measurements (∼1100 fluxes), train an ML that explained 65%–89% variance very few input variables—soil moisture, days after fertilization, texture, air temperature, carbon, precipitation, nitrogen (N) fertilizer rate. When applied long-term test not model, 38% variation observed corn, 51% upon coupling predicted N availability. This represents two three times improvement over conventional substantially fewer requirements. approach offers better predictions thus more precise global effective mitigation interventions.

Язык: Английский

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Greenhouse gas fluxes over managed grasslands in Central Europe

Global Change Biology, Год журнала: 2018, Номер 24(5), С. 1843 - 1872

Опубликована: Фев. 5, 2018

Central European grasslands are characterized by a wide range of different management practices in close geographical proximity. Site-specific strategies strongly affect the biosphere-atmosphere exchange three greenhouse gases (GHG) carbon dioxide (CO2 ), nitrous oxide (N2 O), and methane (CH4 ). The evaluation environmental impacts at site level is challenging, because most situ measurements focus on quantification CO2 exchange, while long-term N2 O CH4 flux ecosystem scale remain scarce. Here, we synthesized , O, fluxes from 14 managed grassland sites, quantified eddy covariance or chamber techniques. We found that were average sink (-1,783 to -91 g m-2 year-1 but source (18-638 -eq. either (-9 488 net GHG balance (NGB) nine sites where all GHGs available was between -2,761 -58 with emissions offsetting concurrent uptake 21 ± 6% across sites. only positive NGB for one during restoration year ploughing. predictive power soil parameters generally low varied considerably within years. However, after site-specific data normalization, identified conditions indicated enhanced source/sink activity ("sweet spots") gave good prediction normalized overall application animal slurry increased emissions. O-N emission factor 1.8 0.5%, among years (0.1%-8.6%). Although led emissions, strength dominant component annual budget.

Язык: Английский

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The Effect of Land-Use Change on Soil CH4 and N2O Fluxes: A Global Meta-Analysis

Ecosystems, Год журнала: 2019, Номер 22(6), С. 1424 - 1443

Опубликована: Март 11, 2019

Язык: Английский

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Nitrous oxide emissions from agricultural soils challenge climate sustainability in the US Corn Belt

Proceedings of the National Academy of Sciences, Год журнала: 2021, Номер 118(46)

Опубликована: Ноя. 8, 2021

Agricultural landscapes are the largest source of anthropogenic nitrous oxide (N2O) emissions, but their specific sources and magnitudes remain contested. In US Corn Belt, a globally important N2O source, in-field soil emissions were reportedly too small to account for measured in regional atmosphere, disproportionately high from intermittent streams have been invoked explain discrepancy. We collected 3 y high-frequency (4-h) measurements across topographic gradient, including very poorly drained (intermittently flooded) depression adjacent upland soils. Mean annual this corn-soybean rotation (7.8 kg N2O-N ha-1⋅y-1) similar previous top-down estimate, regardless landscape position. Synthesizing other Belt studies, we found mean 5.6 ha-1⋅y-1 soils with drainage our transect (moderately well-drained drained), which collectively comprise 60% corn-soybean-cultivated contrast, strictly averaged only 2.3 Our results imply that moderately severely impaired values not representative broader Belt. On basis carbon dioxide equivalents, warming effect direct was twofold greater than optimistic gains achievable agricultural practice changes. Despite recent focus on sequestration, addressing wet may leverage achieving climate sustainability.

Язык: Английский

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Ensemble machine learning for modeling greenhouse gas emissions at different time scales from irrigated paddy fields

Field Crops Research, Год журнала: 2023, Номер 292, С. 108821 - 108821

Опубликована: Янв. 23, 2023

Язык: Английский

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Nitrification inhibitors can increase post-harvest nitrous oxide emissions in an intensive vegetable production system

Scientific Reports, Год журнала: 2017, Номер 7(1)

Опубликована: Март 7, 2017

Abstract To investigate the effect of nitrification inhibitors (NIs) 3,4-dimethylpyrazole phosphate (DMPP) and 3-methylpyrazole 1,2,4-triazole (3MP + TZ), on N 2 O emissions yield from a typical vegetable rotation in sub-tropical Australia we monitored soil fluxes continuously over an entire year using automated greenhouse gas measurement system. The temporal variation showed only low cropping phases, but significantly higher were observed post-harvest accounting for 50–70% annual emissions. NIs reduced by 20–60% phases; however, this mitigation was offset elevated treatments fallow period. Annual conventional fertiliser, DMPP treatment, 3MP TZ treatment 1.3, 1.1 1.6 (sem = 0.2) kg-N ha −1 , respectively. This study highlights that use systems can lead to storing profile is available microbes during decomposition residues. Hence has be treated carefully fertiliser rates need adjusted avoid oversupply phase.

Язык: Английский

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Long‐term nitrous oxide fluxes in annual and perennial agricultural and unmanaged ecosystems in the upper Midwest USA

Global Change Biology, Год журнала: 2016, Номер 22(11), С. 3594 - 3607

Опубликована: Авг. 11, 2016

Differences in soil nitrous oxide (N2 O) fluxes among ecosystems are often difficult to evaluate and predict due high spatial temporal variabilities few direct experimental comparisons. For 20 years, we measured N2 O 11 southwest Michigan USA: four annual grain crops (corn-soybean-wheat rotations) managed with conventional, no-till, reduced input, or biologically based/organic inputs; three perennial (alfalfa, poplar, conifers); unmanaged of different successional age including mature forest. Average emissions were higher from N-fixing cropping systems than nonleguminous low across ecosystems. Among full-rotation indistinguishable one another but rotation phase mattered. example, those cover fertilizer N emitted more during the corn soybean phases, wheat ~40% lower. Likewise, no-till did not differ conventional tillage over entire ~20% increased 30-80% phases. Greenhouse gas intensity for (flux per unit yield) was lowest soybeans produced under management, while other crop × management combinations intensities similar another. fertilized systems, ranged 0.30 1.33 kg O-N ha-1 yr-1 best predicted by IPCC Tier 1 ΔEF emission factor approaches. Annual cumulative explained NO3- pools (r2 = 0.72) so crops, where differences overrode simple correlations. Daily poorly any variables. Overall, long-term measurements reveal lower nonlegume vegetation and, conservatively overriding influence on fluxes.

Язык: Английский

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