Denitrification and nitrous oxide emissions from a Black Chernozemic soil during spring thaw in Alberta

1997 ◽  
Vol 77 (2) ◽  
pp. 153-160 ◽  
Author(s):  
M. Nyborg ◽  
J. W. Laidlaw ◽  
E. D. Solberg ◽  
S. S. Malhi

Previous field research in Alberta has suggested that denitrification occurs mostly when soil thaws in the spring, with associated soil water saturation. Our objective was to determine if denitrification and N2O emission in fact take place in cold, thawing soil in the field. Denitrification and N2O flux were measured in two springs and the intervening summer. Cylinders were placed in soil in November, 1988, and 57 kg N ha−1 of 15Nlabeled KNO3 was added. Soil 15N mass balance technique showed 23 kg N ha−1 of added-N was lost by 15 May 1989. Gas trappings were made (28 March to 29 April) and nearly all of the N2O emission (3.5 kg N2O-N ha−1) occurred during an 11-d period of thaw. The accumulated N2O flux from 20 June to 31 August was small (0.5 kg N2O-N ha−1, or less); during that time there were no rainfall events intense enough to produce water saturated soil. In 1990, 15N-labeled KNO3 (100 kg N ha−1) was applied on 26 March (outset of the thaw) and mass balance showed 32.7 kg N ha−1of added-N was lost by 7 May. A flux of 16.3 kg N2O-N ha−1 occurred largely in a 10-d period during and immediately after soil thaw. The N2O emitted from soil left a considerable fraction of the lost N unaccounted for. This unaccounted N was most likely lost as gaseous N other than N2O (e.g., N2). We conclude that large amounts of soil nitrate may be denitrified, with smaller amounts emitted as N2O, as the soil thaws and soon thereafter. Key words: Denitrification, frozen soil, thawing soil, nitrogen, nitrous oxide

1987 ◽  
Vol 67 (4) ◽  
pp. 825-834 ◽  
Author(s):  
M. S. AULAKH ◽  
D. A. RENNIE

The effects of wheat straw incorporation on denitrification, immobilization of N, and C mineralization were investigated at H2O contents of 60, 90 and 120% saturation. Incorporation of increasing levels of straw consistently increased the rate of denitrification for the first 4–8 d, followed by negligible N losses thereafter. In a total period of 96 d, the addition of 1.0% straw increased N losses from 2.5 to 10.1, and from 61.6 to 83.9 μg g−1 in the 60 and 120% water saturation treatments, respectively. The pattern of CO2-C evolved was practically identical to that of the denitrification rate for the initial period when sufficient [Formula: see text] was present. This study has confirmed that in flooded soils, high rates of denitrification will persist only when C is supplied by native or applied organic C sources, provided adequate [Formula: see text] is present. When [Formula: see text] was low, denitrification rates rapidly decreased, even with a sufficient supply of C. Immobilization of fertilizer N (50 μg N g−1 as K15NO3) was very rapid. Around 90% of the total immobilization of applied N occurred within 4 d. Incorporation of 1.0% straw increased the immobilization of fertilizer N from 8.4 to 42.8, and from 1.0 to 7.6% in the 60 and 120% water-saturated treatments, respectively. Remineralization of recently immobilized fertilizer N was observed after 32 d in the 60% saturation treatments only. Key words: Denitrification, wheat straw, mineralization of N


2019 ◽  
Vol 62 (5) ◽  
pp. 1173-1183
Author(s):  
David B. Parker ◽  
Kenneth D. Casey ◽  
Heidi M. Waldrip ◽  
Byeng R. Min ◽  
Bryan L. Woodbury ◽  
...  

Abstract. Nitrous oxide (N2O) is a greenhouse gas (GHG) with a global warming potential much greater than that of carbon dioxide (CO2). Nitrous oxide is emitted from the manure-covered pen surfaces of open-lot beef cattle feedyards, and more than six million beef cattle are fed in the Southern Great Plains. A field research project was conducted to determine the temporal and spatial variability of N2O emissions from the pen surfaces of a commercial feedyard before and after simulated rainfall. Two week-long monitoring cycles were conducted in April and August 2018 in the Texas Panhandle. Temporal variability was assessed using six continuous automated flux chambers per pen, and spatial variability was assessed using a portable chamber at up to 61 locations in a single pen. Diurnal fluxes varied 5-fold to 10-fold over a 24 h period. Flux varied seasonally, with arithmetic means of 0.56 mg N2O-N m-2 h-1 in April and 3.21 mg N2O-N m-2 h-1 in August. Fluxes measured spatially across the pen surface over a 2 h period at midday were lognormally distributed, with April geometric and arithmetic means of -0.81 and 0.80 mg N2O-N m-2 h-1, respectively, and August geometric and arithmetic means of 0.095 and 2.6 mg N2O-N m-2 h-1, respectively. Fluxes peaked shortly after simulated rainfall. Arithmetic mean N2O-N flux for the 2 d after rainfall increased over the background level by 4.6-fold in April and 1.7-fold in August. Manure properties measured at the time of flux measurement were poorly correlated with N2O emissions and were of little value for predicting N2O emissions, which confirmed that further work is warranted on the biochemistry of feedyard manure. The results of this field research will help refine models for predicting N2O emissions from open-lot beef cattle feedyards and help to develop effective mitigation methods to conserve feedyard N. Keywords: Beef cattle, Flux chamber, Greenhouse gas, Manure, Nitrous oxide, Rainfall.


1984 ◽  
Vol 64 (2) ◽  
pp. 187-194 ◽  
Author(s):  
L. L. GOODROAD ◽  
D. R. KEENEY

We, as well as others, have observed that nitrous oxide (N2O) fluxes increased markedly during soil thaw in early spring. This phenomenon was examined further by determining nitrous oxide concentrations in the soil profile and N2O fluxes from the soil surface during the winter-spring period and evaluating physical release and microbial production of N2O on thawing of frozen soil cores in the laboratory. In mid-winter, soil profile N2O concentrations were close to ambient and surface N2O fluxes were low. At thawing, high N2O concentrations (ranging from 1082 to 2066 mg∙m−3) were found at 10–30 cm in the soil profiles of a coniferous forest, and in manure- and straw-treated plots. Concurrently, N2O flux increased markedly and reached some of the highest values observed during the entire season. When thawing was complete, soil profile N2O concentrations and N2O flux declined. Soil cores were taken from frozen soil, warmed in the laboratory, and N2O release measured. Nitrous oxide was released on warming, and cores treated with CHCl3 had a slower release rate. The results indicate that some of the N2O flux occurring at thawing is due in part to physical release of N2O, and that additional N2O is likely produced by denitrification. Key words: Nitrous oxide, denitrification, frozen soils, nitrogen loss


2008 ◽  
Vol 88 (2) ◽  
pp. 133-143 ◽  
Author(s):  
K M Gillam ◽  
B J Zebarth ◽  
D L Burton

National inventories of N2O emissions from agricultural situations are being developed; however, the factors controlling such emissions may vary with soil and environmental conditions and management practices. This study determined the relative importance of soil aeration, as measured by water-filled pore space (WFPS), NO3− addition, C addition and C source on the amount and partitioning of gaseous N losses from denitrification from an arable soil in Atlantic Canada. Denitrification (N2O + N2) and N2O emissions were measured on repacked soil cores using acetylene inhibition.The N2O:(N2O + N2) ratio was frequently 0.7 or higher, indicating that most emissions occurred as N2O. N2O emissions and denitrification were negligible at a WFPS of 0.45 m3 m-3, and high at WFPS of 0.75 m3 m-3, regardless of NO3−or C addition treatments. At a WFPS of 0.60 m3 m-3, N2O emissions and denitrification were low and were increased by both NO3− and C addition treatments. Carbon source was investigated by amendment with glucose, red clover or barley straw. Based on the quantity of soil respiration per unit of C added in the amendment, C in the red clover and barley straw was estimated to be 48 and 28% as available as glucose C. When corrected for C availability, cumulative N2O emissions averaged 0.010, 0.011 and 0.002 mg N kg-1 soil, and cumulative denitrification averaged 0.014, 0.014 and 0.003 mg N kg-1 soil, for each 1.0 mg C kg-1 soil of available C added as glucose, red clover or barley straw, respectively. NO3− addition had no effect on denitrification, but increased N2O emissions, especially where C availability was high. The amount of denitrification was controlled primarily by soil O2 supply, as controlled by WFPS and C availability. The N2O:(N2O + N2) ratio was generally high in cases where the supply of O2 or NO3− was sufficient to meet the demand for terminal electron acceptors. Key words: Denitrification, nitrous oxide, glucose, red clover, barley straw, carbon availability, terminal electron acceptor, aeration


2011 ◽  
Vol 37 (9) ◽  
pp. 1666-1675
Author(s):  
Hai-Ming TANG ◽  
Xiao-Ping XIAO ◽  
Wen-Guang TANG ◽  
Guang-Li YANG

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.


Eos ◽  
2008 ◽  
Vol 89 (51) ◽  
pp. 529 ◽  
Author(s):  
Stephen J. Del Grosso ◽  
Tom Wirth ◽  
Stephen M. Ogle ◽  
William J. Parton

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