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

2021 ◽  
Vol 118 (46) ◽  
pp. e2112108118
Author(s):  
Nathaniel C. Lawrence ◽  
Carlos G. Tenesaca ◽  
Andy VanLoocke ◽  
Steven J. Hall
Keyword(s):  
Nitrous Oxide ◽  
Soil Carbon ◽  
Agricultural Soils ◽  
Agricultural Landscapes ◽  
Nitrous Oxide Emissions ◽  
Corn Belt ◽  
Agricultural Practice ◽  
Mean Values ◽  
The Us ◽  
Soil Emissions

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

scholarly journals Nitrous oxide emissions are enhanced in a warmer and wetter world

2017 ◽  
Vol 114 (45) ◽  
pp. 12081-12085 ◽  
Author(s):  
Timothy J. Griffis ◽  
Zichong Chen ◽  
John M. Baker ◽  
Jeffrey D. Wood ◽  
Dylan B. Millet ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Interannual Variability ◽  
Radiative Forcing ◽  
Emission Factor ◽  
Stratospheric Ozone ◽  
Nitrous Oxide Emissions ◽  
Corn Belt ◽  
Emission Mitigation ◽  
The Us ◽  
Agricultural Regions

Nitrous oxide (N2O) has a global warming potential that is 300 times that of carbon dioxide on a 100-y timescale, and is of major importance for stratospheric ozone depletion. The climate sensitivity of N2O emissions is poorly known, which makes it difficult to project how changing fertilizer use and climate will impact radiative forcing and the ozone layer. Analysis of 6 y of hourly N2O mixing ratios from a very tall tower within the US Corn Belt—one of the most intensive agricultural regions of the world—combined with inverse modeling, shows large interannual variability in N2O emissions (316 Gg N2O-N⋅y−1to 585 Gg N2O-N⋅y−1). This implies that the regional emission factor is highly sensitive to climate. In the warmest year and spring (2012) of the observational period, the emission factor was 7.5%, nearly double that of previous reports. Indirect emissions associated with runoff and leaching dominated the interannual variability of total emissions. Under current trends in climate and anthropogenic N use, we project a strong positive feedback to warmer and wetter conditions and unabated growth of regional N2O emissions that will exceed 600 Gg N2O-N⋅y−1, on average, by 2050. This increasing emission trend in the US Corn Belt may represent a harbinger of intensifying N2O emissions from other agricultural regions. Such feedbacks will pose a major challenge to the Paris Agreement, which requires large N2O emission mitigation efforts to achieve its goals.

scholarly journals Use of Artificial Neural Networks in Predicting Direct Nitrous Oxide Emissions from Agricultural Soils

2013 ◽  
Vol 20 (2) ◽  
pp. 419-428 ◽  
Author(s):  
Alicja Kolasa-Więcek
Keyword(s):  
Neural Networks ◽  
Sensitivity Analysis ◽  
Nitrous Oxide ◽  
Artificial Neural Networks ◽  
Agricultural Soils ◽  
Organic Fertilizers ◽  
Nitrous Oxide Emissions ◽  
Multilayer Perceptrons ◽  
Soil Emissions ◽  
Artificial Neural

Abstract Agricultural greenhouse gases emissions are mainly produced in direct emissions from plant and animal production as well as those associated with land use changes. Agriculture is a major source of atmospheric nitrous oxide (N2O). N2O emissions from agricultural production has the source primarily in soil fertilized by mineral and organic fertilizers. In Poland, agricultural soils are responsible for 77.1% of emissions. Emissions associated with the animal manner farming amount 22.8%. Studies attempt to modeling and predicting of N2O emissions from Direct Soil Emissions in relation to the use of crops and livestock population. In the analysis an artificial neural networks were used. The best values showing the quality of neural regression model were obtained by multilayer perceptrons MLP. Based on the sensitivity analysis, attempts were taken to determine the extent of the contribution of each selected variables on the estimate of the direct emissions of N2O from agricultural soils. The sensitivity analysis of designed network on the structure MLP 9-4-1 shows that the amount of nitrogen fertilizer consumption has the biggest share in the shaping of N2O emissions from Direct Soil Emissions. The sensitivity analysis of network on the structure MLP 16-5-1 pointed to participate cattle and pigs as the most important in the formation of N2O emissions from Direct Soil Emissions. Among the crops in Poland, which may affect the release of N2O stands out rapeseed and rye. The study was conducted using the statistical package Statistica v. 10.0.

Soil nitrous oxide emissions from agricultural soils in Canada: Exploring relationships with soil, crop and climatic variables

2018 ◽  
Vol 254 ◽  
pp. 69-81 ◽  
Author(s):  
Philippe Rochette ◽  
Chang Liang ◽  
David Pelster ◽  
Onil Bergeron ◽  
Reynald Lemke ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Agricultural Soils ◽  
Climatic Variables ◽  
Nitrous Oxide Emissions

Reconciling the differences between top-down and bottom-up estimates of nitrous oxide emissions for the U.S. Corn Belt

2013 ◽  
Vol 27 (3) ◽  
pp. 746-754 ◽  
Author(s):  
T. J. Griffis ◽  
X. Lee ◽  
J. M. Baker ◽  
M. P. Russelle ◽  
X. Zhang ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Nitrous Oxide Emissions ◽  
Corn Belt ◽  
Top Down ◽  
Bottom Up ◽  
The U.S

The effects of spatial variability of nitrous oxide emissions from grazed pastures on the sampling distribution of chamber measurements

2015 ◽  
Vol 154 (2) ◽  
pp. 223-241 ◽  
Author(s):  
D. L. GILTRAP ◽  
A. J. R. GODFREY
Keyword(s):  
Nitrous Oxide ◽  
Spatial Variability ◽  
Agricultural Soils ◽  
Geometric Mean ◽  
Arithmetic Mean ◽  
Nitrous Oxide Emissions ◽  
Sample Mean ◽  
Grazed Pastures ◽  
Urine Patch ◽  
The Mean

SUMMARYChamber sampling is a common method for measuring nitrous oxide (N2O) emissions from agricultural soils. However, for grazed pastures, the patchy nature of urine deposition results in very high levels of spatial variability in N2O emissions. In the present study, the behaviour of the sample mean was examined by simulating a large number (9999) of random N2O chamber samples under different assumptions regarding the underlying N2O distribution. Using sample sizes of up to 100 chambers, the Central Limit Theorem did not apply. The distribution of the sample mean was always right-skewed with a standard deviation varying between 12·5 and 135% of the true mean. However, the arithmetic mean was an unbiased estimator and the mean of the sample mean distribution was close to the true mean of the simulated N2O distribution. The properties of the sample mean distribution (variance, skewness) were affected significantly by the assumed distribution of the emission factor, but not by distribution of the urine patch concentration. The geometric mean was also investigated as a potential alternative estimator. However, although its distribution had lower variance, it was also biased. Two methods for bias correcting the mean were investigated. These methods reduced the bias, but at the cost of increasing the variance. Neither of the bias-corrected estimators were consistently better than the arithmetic mean in terms of skewness and variance. To improve the estimation of N2O emissions from a grazed pasture using chambers, techniques need to be developed to identify urine patch and non-urine patch areas before sampling.

scholarly journals The use of agricultural soils as a source of nitrous oxide emission in selected communes of Poland

2017 ◽  
Vol 13 (1) ◽  
pp. 39-49
Author(s):  
Paweł Wiśniewski ◽  
Mariusz Kistowski
Keyword(s):  
Nitrous Oxide ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Agricultural Soils ◽  
Nitrous Oxide Emissions ◽  
Organic Soils ◽  
Low Carbon ◽  
Gas Emissions ◽  
Low Carbon Economy ◽  
Carbon Economy

Abstract Nitrous oxide (N2O) is one of the main greenhouse gases, with a nearly 300 times greater potential to produce a greenhouse effect than carbon dioxide (CO2). Almost 80% of the annual emissions of this gas in Poland come from agriculture, and its main source is the use of agricultural soils. The study attempted to estimate the N2O emission from agricultural soils and to indicate its share in the total greenhouse gas emissions in 48 Polish communes. For this purpose, a simplified solution has been proposed which can be successfully applied by local government areas in order to assess nitrous oxide emissions, as well as to monitor the impact of actions undertaken to limit them. The estimated emission was compared with the results of the baseline greenhouse gas inventory prepared for the needs of the low-carbon economy plans adopted by the studied self-governments. This allowed us to determine the share of N2O emissions from agricultural soils in the total greenhouse gas emissions of the studied communes. The annual N2O emissions from agricultural soils in the studied communes range from 1.21 Mg N2O-N to 93.28 Mg N2O-N, and the cultivation of organic soils is its main source. The use of mineral and natural fertilisers, as well as indirect emissions from nitrogen leaching into groundwater and surface waters, are also significant. The results confirm the need to include greenhouse gas emissions from the use of agricultural soils and other agricultural sources in low-carbon economy plans.

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