Atmosphere composition and N2O emissions in soils of contrasting textures fertilized with anhydrous ammonia

2004 ◽  
Vol 84 (3) ◽  
pp. 339-352 ◽  
Author(s):  
Philippe Rochette, Régis R. Simard ◽  
Noura Ziadi, Michel C. Nolin ◽  
Athyna N. Cambouris

Nitrous oxide production and emission in agricultural soils are often influenced by soil physical properties and mineral N content. An experiment was initiated on a commercial farm located in the St. Lawrence Lowlands to measure the effects of recommended (150 kg N ha-1) and excessive (250 kg N ha-1) rates of anhydrous ammonia on atmospheric composition (O2, CO2, CH4 and N2O) and N2O emissions in soils of contrasting textures (sandy loam, clay loam and clay) cropped to corn. N2O emissions and soil temperature, water content and atmospheric composition were measured from post-harvest tillage to the first snowfall during the first year (2000), and from spring thaw to mid-July during the following 2 yr. Episodes of high N2O concentrations and surface emissions coincided with periods of high soil water content shortly following rainfall events when soil O2 concentrations were lowest. The convergence of indicators of restricted soil aeration at the time of highest N2O production suggested that denitrification was a major contributor to N2O emissions even in soils receiving an NH4-based fertilizer. Soil texture had a significant influence on soil N2O concentration and emission rates on several sampling dates. However, the effect was relatively small and it was not consistent, likely because of complex interactions between soil physical properties and N2O production, consumption and diffusion processes. Nitrous oxide emissions during the study were not limited by soil N availability as indicated by similar fluxes at recommended and excessive rates of anhydrous ammonia. Finally, greater N2O emissions in 2001 than in 2002 stress the importance of multiyear studies to evaluate the effect of annual weather conditions on soil N2O dynamics. Key words: Greenhouse gasses, denitrification

Soil Research ◽  
2019 ◽  
Vol 57 (4) ◽  
pp. 342 ◽  
Author(s):  
G. D. Schwenke ◽  
B. M. Haigh

Delaying the accumulation of soil nitrate from urea applied at sowing should mitigate nitrous oxide (N2O) emissions without compromising optimum crop production. This delay may be achieved chemically using a nitrification inhibitor such as 3,4 dimethylpyrazole phosphate (DMPP), or physically by coating urea with a degradable polymer (PCU). In five field experiments across three summers, the impact of DMPP-coated urea applied at sowing on soil mineral nitrogen (N), N2O emissions and yields of grain sorghum or sunflower grown on sub-tropical Vertosols was assessed. At two experiments, DMPP effects on plant N uptake, soil N movement and total N loss were determined with 15N. One experiment included PCU and several blends: urea+DMPP-urea; urea+PCU; urea+DMPP-urea+PCU. Averaged across all experiments, DMPP reduced cumulative N2O emitted by 92% (range: 65–123%) and N2O emission factor (EF: percent of applied N emitted) by 88%. There was no statistical difference in N2O emitted between the 0N control and DMPP-urea. PCU reduced N2O emitted by 27% and EF by 34%. The urea+DMPP-urea blend also nullified urea-induced N2O, but urea+PCU increased N2O emissions and decreased grain yield due to a mismatch between soil N availability and plant N demand. DMPP arrested 15N movement in soil and reduced total 15N loss from 35% to 15% at one of the two 15N experiments. Applying DMPP-urea at sowing is an effective N strategy that nullifies urea-induced N2O emissions, maintains crop yield, and retains N in the soil–plant system. Negative impacts of the PCU+urea blend highlight the influence of growing season conditions on fertiliser N release.


2021 ◽  
Author(s):  
Arezoo Taghizadeh-Toosi ◽  
Baldur Janz ◽  
Rodrigo Labouriau ◽  
Jørgen E. Olesen ◽  
Klaus Butterbach-Bahl ◽  
...  

2008 ◽  
Vol 88 (2) ◽  
pp. 219-227 ◽  
Author(s):  
D L Burton ◽  
Xinhui Li ◽  
C A Grant

Fertilizer nitrogen use is estimated to be a significant source of nitrous oxide (N2O) emissions in western Canada. These estimates are based primarily on modeled data, as there are relatively few studies that provide direct measures of the magnitude of N2O emissions and the influence of N source on N2O emissions. This study examined the influence of nitrogen source (urea, coated urea, urea with urease inhibitor, and anhydrous ammonia), time of application (spring, fall) and method of application (broadcast, banded) on nitrous oxide emissions on two Black Chernozemic soils located near Winnipeg and Brandon Manitoba. The results of this 3-yr study demonstrated consistently that the rate of fertilizer-induced N2O emissions under Manitoba conditions was lower than the emissions estimated using Intergovernmental Panel on Climate Change (IPCC) coefficients. The Winnipeg site tended to have higher overall N2O emissions (1.7 kg N ha-1) and fertilizer-induced emissions (~0.8% of applied N) than did the Brandon site (0.5 kg N ha-1), representing ~0.2% of applied N. N2O emissions in the first year of the study were much higher than in subsequent years. Both the site and year effects likely reflected differences in annual precipitation. The N2O emissions associated with the use of anhydrous ammonia as a fertilizer source were no greater than emissions with urea. Fall application of nitrogen fertilizer tended to result in marginally greater N2O emissions than did spring application, but these differences were neither large nor consistent. Key words: Nitrogen fertilizer, nitrous oxide emissions, nitrate intensity, anhydrous ammonia, urea


Soil Research ◽  
2018 ◽  
Vol 56 (8) ◽  
pp. 810 ◽  
Author(s):  
Iris Vogeler ◽  
Rogerio Cichota

Despite the importance of soil physical properties on water infiltration and redistribution, little is known about the effect of variability in soil properties and its consequent effect on contaminant loss pathways. To investigate the effects of uncertainty and heterogeneity in measured soil physical parameters on the simulated movement of water and the prediction of nitrous oxide (N2O) emissions, we set up the Agricultural Production Systems sIMulator (APSIM) for different soil types in three different regions of New Zealand: the Te Kowhai silt loam and the Horotiu silt loam in the Waikato region, and the Templeton silt loam in the Canterbury region, and the Otokia silt loam and the Wingatui silt loam in the Otago region. For each of the soil types, various measured soil profile descriptions, as well as those from a national soils database (S-map) were used when available. In addition, three different soil water models in APSIM with different complexities (SWIM2, SWIM3, and SoilWat) were evaluated. Model outputs were compared with temporal soil water content measurements within the top 75mm at the various experimental sites. Results show that the profile description, as well as the soil water model used affected the prediction accuracy of soil water content. The smallest difference between soil profile descriptions was found for the Templeton soil series, where the model efficiency (NSE) was positive for all soil profile descriptions, and the RMSE ranged from 0.055 to 0.069m3/m3. The greatest difference was found for the Te Kowhai soil, where only one of the descriptions showed a positive NSE, and the other two profile descriptions overestimated measured topsoil water contents. Furthermore, it was shown that the soil profile description highly affects N2O emissions from urinary N deposited during animal grazing. However, the relative difference between the emissions was not always related to the accuracy of the measured soil water content, with soil organic carbon content also affecting emissions.


Soil Research ◽  
2012 ◽  
Vol 50 (2) ◽  
pp. 125 ◽  
Author(s):  
Tony J. van der Weerden ◽  
Francis M. Kelliher ◽  
Cecile A. M. de Klein

Nitrous oxide (N2O) emissions from agricultural soils have been estimated to comprise about two-thirds of the biosphere’s contribution of this potent greenhouse gas. In pasture systems grazed by farmed animals, where substrate is generally available, spatial variation in emissions, in addition to that cause by the patchiness of urine deposition, has been attributed to soil aeration, as governed by gas diffusion. However, this parameter is not readily measured, and the soil’s water-filled pore space (WFPS) has often been used as a proxy, despite gas diffusion in soils depending on the volumetric fractions of water and air. With changing water content, these fractions will reflect the soil’s pore size distribution. The aims of this study were: (i) to determine if the pore size distribution of two pastoral soils explains previously observed differences in N2O emissions under field conditions, and (ii) to assess the most appropriate soil water/gas diffusion metric for estimating N2O emissions. The N2O emissions were measured from intact cores of two soils (one classified as well drained and one as poorly drained) that had been sampled to a depth of 50 mm beneath grazed pasture. Nitrogen (N, 500 kg N/ha) was applied to soil cores as aqueous nitrate solution, and the cores were drained under controlled conditions at a constant temperature. The poorly drained soil had a larger proportion of macropores (23.5 v. 18.7% in the well-drained soil), resulting in more rapid drainage and increased pore continuity, thereby reducing the duration of anaerobicity, and leading to lower N2O emissions. Emissions were related to three soil water proxies including WFPS, volumetric water content (VWC), and matric potential (MP), and to relative diffusion (RD). All parameters showed highly significant relationships with N2O emissions (P < 0.001), with RD, WFPS, VWC, and MP accounting for 59, 72, 88, and 93% of the variability, respectively. As VWC is more readily determined than MP, the former is potentially more suitable for estimating N2O emission from different soils across a range of time and space scales under field conditions.


Soil Research ◽  
2018 ◽  
Vol 56 (7) ◽  
pp. 752
Author(s):  
Graeme Schwenke ◽  
Annabelle McPherson

Nitrogen (N) fertiliser inputs for irrigated cotton production are rapidly increasing to support ever-increasing yields, but much of the applied N may be lost as N gases, including nitrous oxide (N2O), via denitrification in medium–heavy clay soils. The addition of a nitrification inhibitor can reduce overall N loss and N2O emissions. Currently, nitrapyrin (2-chloro-6-trichloro methyl pyridine) is the only inhibitor used with anhydrous ammonia (AA), whereas 3,4-dimethyl pyrazole phosphate (DMPP) has potentially greater stability and longevity in soil, but is not compatible with AA. A newly-developed formulation based on DMPP, 3,4-dimethyl pyrazole tetra-methylene sulfone (DMPS), can be direct-injected with AA. We compared N2O emissions from DMPS- and nitrapyrin-treated AA from two Vertosols used for irrigated cotton. At Emerald (Queensland), both inhibitors reduced N2O emitted by 77% over 2 months. At Gunnedah (New South Wales), DMPS was active in the soil for 3 months, reducing N2O by 86%, whereas nitrapyrin activity lasted for 2 months and reduced N2O by 65%. Realising the potential for improved environmental benefits from directly injecting DMPS with AA requires an agronomic benefit justifying its additional cost to the farmer. Future research needs to investigate the potential for reduced N rates when using these inhibitors – without compromising high yields.


Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 469 ◽  
Author(s):  
Ryan Farquharson

Laboratory incubations were performed to estimate nitrification rates and the associated nitrous oxide (N2O) emissions under aerobic conditions on a range of soils from National Agricultural Nitrous Oxide Research Program field sites. Significant site-to-site variability in nitrification rates and associated N2O emissions was observed under standardised conditions, indicating the need for site-specific model parameterisation. Generally, nitrification rates and N2O emissions increased with higher water content, ammonium concentration and temperature, although there were exceptions. It is recommended that site-specific model parameterisation be informed by such data. Importantly, the ratio of N2O emitted to net nitrified N under aerobic conditions was small (<0.2% for the majority of measurements) but did vary from 0.03% to 1%. Some models now include variation in the proportion of nitrified N emitted as N2O as a function of water content; however, strong support for this was not found across all of our experiments, and the results demonstrate a potential role of pH and ammonium availability. Further research into fluctuating oxygen availability and the coupling of biotic and abiotic processes will be required to progress the process understanding of N2O emissions from nitrification.


Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 500 ◽  
Author(s):  
Nigel Swarts ◽  
Kelvin Montagu ◽  
Garth Oliver ◽  
Liam Southam-Rogers ◽  
Marcus Hardie ◽  
...  

Nitrous oxide (N2O) emissions contribute 6% of the global warming effect and are derived from the activity of soil-based microorganisms involved in nitrification and denitrification processes. There is a paucity of greenhouse gas emissions data for Australia’s horticulture industry. In this study we investigated N2O flux from two deciduous fruit tree crops, apples and cherries, in two predominant growing regions in eastern Australia, the Huon Valley in southern Tasmania (Lucaston – apples and Lower Longley – cherries), and high altitude northern New South Wales (Orange – apples and Young – cherries). Estimated from manual chamber measurements over a 12-month period, average daily emissions were very low ranging from 0.78gN2O-Nha–1day–1 in the apple orchard at Lucaston to 1.86gN2O-Nha–1day–1 in the cherry orchard in Lower Longley. Daily emissions were up to 50% higher in summer (maximum 5.27gN2O-Nha–1day–1 at Lower Longley) than winter (maximum 2.47gN2O-Nha–1day–1 at Young) across the four trial orchards. N2O emissions were ~40% greater in the inter-row than the tree line for each orchard. Daily flux rates were used as a loss estimate for annual emissions, which ranged from 298gN2O-Nha–1year–1 at Lucaston to 736gN2O-Nha–1year–1 at Lower Longley. Emissions were poorly correlated with soil temperature, volumetric water content, water filled porosity, gravimetric water content and matric potential – with inconsistent patterns between sites, within the tree line and inter-row and between seasons. Stepwise linear regression models for the Lucaston site accounted for less than 10% of the variance in N2O emissions, for which soil temperature was the strongest predictor. N2O emissions in deciduous tree crops were among the lowest recorded for Australian agriculture, most likely due to low rates of N fertiliser, cool temperate growing conditions and highly efficient drip irrigation systems. We recommend that optimising nutrient use efficiency with improved drainage and a reduction in soil compaction in the inter-row will facilitate further mitigation of N2O emissions.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Khadim Dawar ◽  
Shah Fahad ◽  
M. M. R. Jahangir ◽  
Iqbal Munir ◽  
Syed Sartaj Alam ◽  
...  

AbstractIn this study, we explored the role of biochar (BC) and/or urease inhibitor (UI) in mitigating ammonia (NH3) and nitrous oxide (N2O) discharge from urea fertilized wheat cultivated fields in Pakistan (34.01°N, 71.71°E). The experiment included five treatments [control, urea (150 kg N ha−1), BC (10 Mg ha−1), urea + BC and urea + BC + UI (1 L ton−1)], which were all repeated four times and were carried out in a randomized complete block design. Urea supplementation along with BC and BC + UI reduced soil NH3 emissions by 27% and 69%, respectively, compared to sole urea application. Nitrous oxide emissions from urea fertilized plots were also reduced by 24% and 53% applying BC and BC + UI, respectively, compared to urea alone. Application of BC with urea improved the grain yield, shoot biomass, and total N uptake of wheat by 13%, 24%, and 12%, respectively, compared to urea alone. Moreover, UI further promoted biomass and grain yield, and N assimilation in wheat by 38%, 22% and 27%, respectively, over sole urea application. In conclusion, application of BC and/or UI can mitigate NH3 and N2O emissions from urea fertilized soil, improve N use efficiency (NUE) and overall crop productivity.


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