Assessing the impacts of tillage, cover crops, nitrification, and urease inhibitors on nitrous oxide emissions over winter and early spring

Oilseed rape (Brassica napus L.) is an important bioenergy crop that contributes to the diversification of renewable energy supply and mitigation of fossil fuel CO2 emissions. Typical oilseed rape crop management includes the use of nitrogen (N) fertilizer and the incorporation of oilseed rape straw into soil after harvest. However, both management options risk increasing soil emissions of nitrous oxide (N2O). The aim of this 2-years field experiment was to identify the regulating factors of N cycling with emphasis on N2O emissions during the post-harvest period. As well as the N2O emission rates, soil ammonia (NH4+) and nitrate (NO3−) contents, crop residue and seed yield were also measured. Treatments included variation of fertilizer (non-fertilized, 90 and 180 kg N ha−1) and residue management (straw remaining, straw removal). Measured N2O emission data showed large intra- and inter-annual variations ranging from 0.5 (No-fert + str) to 1.0 kg N2O-N ha−1 (Fert-180 + str) in 2013 and from 4.1 (Fert-90 + str) to 7.3 kg N2O-N ha−1 (No-fert + str) in 2014. Cumulative N2O emissions showed that straw incorporation led to no difference or slightly reduced N2O emissions compared with treatments with straw removal, while N fertilization has no effect on post-harvest N2O emissions. A process-based model, CoupModel, was used to explain the large annual variation of N2O after calibration with measured environmental data. Both modeled and measured data suggest that soil water-filled pore space and temperature were the key factors controlling post-harvest N2O emissions, even though the model seemed to show a higher N2O response to the N fertilizer levels than our measured data. We conclude that straw incorporation in oilseed rape cropping is environmentally beneficial for mitigating N2O losses. The revealed importance of climate in regulating the emissions implies the value of multi-year measurements. Future studies should focus on new management practices to mitigate detrimental effects caused by global warming, for example by using cover crops.

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Does 3,4-dimethylpyrazole phosphate or N-(n-butyl) thiophosphoric triamide reduce nitrous oxide emissions from a rain-fed cropping system?

Soil Research ◽

10.1071/sr17219 ◽

2018 ◽

Vol 56 (3) ◽

pp. 296 ◽

Cited By ~ 4

Author(s):

Guangdi D. Li ◽

Graeme D. Schwenke ◽

Richard C. Hayes ◽

Hongtao Xing ◽

Adam J. Lowrie ◽

...

Keyword(s):

Nitrous Oxide ◽

Grain Yield ◽

Crop Yields ◽

Cropping System ◽

N2o Emission ◽

Nitrous Oxide Emissions ◽

Wheat Crop ◽

N2o Emissions ◽

Urease Inhibitors ◽

Eastern Australia

Nitrification and urease inhibitors have been used to reduce nitrous oxide (N2O) emissions and increase nitrogen use efficiency in many agricultural systems. However, their agronomic benefits, such as the improvement of grain yield, is uncertain. A two-year field experiment was conducted to (1) investigate whether the use of 3,4-dimethylpyrazole phosphate (DMPP) or N-(n-butyl) thiophosphoric triamide (NBPT) can reduce N2O emissions and increase grain yield and (2) explore the financial benefit of using DMPP or NBPT in a rain-fed cropping system in south-eastern Australia. The experiment was conducted at Wagga Wagga, New South Wales, Australia with wheat (Triticum aestivum L.) in 2012 and canola (Brassica napus L.) in 2013. Results showed that urea coated with DMPP reduced the cumulative N2O emission by 34% for a wheat crop in 2012 (P < 0.05) and by 62% for a canola crop in 2013 (P < 0.05) compared with normal urea, but urea coated NBPT had no effect on N2O emission for the wheat crop in 2012. Neither nitrification nor urease inhibitors increased crop yields because the low rainfall experienced led to little potential for gross N loss through denitrification, leaching or volatilisation pathways. In such dry years, only government or other financial incentives for N2O mitigation would make the use of DMPP with applied N economically viable.

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Ammonia and nitrous oxide emissions as affected by nitrification and urease inhibitors

Journal of soil science and plant nutrition ◽

10.4067/s0718-95162018005001501 ◽

2018 ◽

pp. 0-0 ◽

Cited By ~ 3

Author(s):

Marta Alfaro ◽

Francisco Salazar ◽

Sara Hube ◽

Luis Ramírez ◽

Ma. Soledad Mora

Keyword(s):

Nitrous Oxide ◽

Nitrous Oxide Emissions ◽

Urease Inhibitors

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Nitrous oxide emissions from soils amended by cover-crops and under plastic film mulching: Fluxes, emission factors and yield-scaled emissions

Atmospheric Environment ◽

10.1016/j.atmosenv.2017.01.007 ◽

2017 ◽

Vol 152 ◽

pp. 377-388 ◽

Cited By ~ 20

Author(s):

Gil Won Kim ◽

Suvendu Das ◽

Hyun Young Hwang ◽

Pil Joo Kim

Keyword(s):

Nitrous Oxide ◽

Cover Crops ◽

Emission Factors ◽

Nitrous Oxide Emissions ◽

Plastic Film ◽

Plastic Film Mulching ◽

Film Mulching

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NITROUS OXIDE EMISSIONS FROM SOILS DURING THAWING

Canadian Journal of Soil Science ◽

10.4141/cjss84-020 ◽

1984 ◽

Vol 64 (2) ◽

pp. 187-194 ◽

Cited By ~ 98

Author(s):

L. L. GOODROAD ◽

D. R. KEENEY

Keyword(s):

Nitrous Oxide ◽

Soil Profile ◽

Nitrogen Loss ◽

Coniferous Forest ◽

Soil Surface ◽

Early Spring ◽

Frozen Soil ◽

Nitrous Oxide Emissions ◽

Soil Cores ◽

Key Words Nitrous Oxide

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

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Nitrous oxide emissions with enhanced efficiency and conventional urea fertilizers in winter wheat

Nutrient Cycling in Agroecosystems ◽

10.1007/s10705-021-10118-9 ◽

2021 ◽

Author(s):

Haibo An ◽

Jen Owens ◽

Brian Beres ◽

Yuejin Li ◽

Xiying Hao

Keyword(s):

Nitrous Oxide ◽

Winter Wheat ◽

Nitrification Inhibitor ◽

Field Trials ◽

Early Spring ◽

Nitrous Oxide Emissions ◽

Nitrification Inhibitors ◽

Late Fall ◽

Coated Urea ◽

Polymer Coated Urea

AbstractOptimizing nitrogen fertilizer management can reduce nitrous oxide (N2O) emissions. This study tested if split applying enhanced efficiency fertilizers (EEFs) resulted in lower N2O emissions than applying equivalent rates of urea at planting. In semiarid southern Alberta, field trials were conducted during three years (planting to harvest) in rainfed winter wheat crops. Annual fertilizer rates ranged from 146 to 176 kg N ha−1. Fertilizer types were urea, and three EEFs (polymer-coated urea, urea with urease and nitrification inhibitors, and urea with a nitrification inhibitor). Each fertilizer type was applied three ways: 100% banded at planting, split applied 30% banded at planting and 70% broadcast in late fall, and split applied 30% banded at planting and 70% broadcast at Feekes growth stage 4 (GS4, post-tiller formation, wheat entering the greening up phase in the early spring). Nitrous oxide was measured using static chambers between sub-weekly and monthly from planting to harvest. Over three years, cumulative N2O emissions ranged from 0.16 to 1.32 kg N ha−1. This was equivalent to emissions factors between 0.009 and 0.688%. Cumulative N2O emissions and emissions factors did not differ between fertilizer types, but they were lower when fertilizer was split applied at GS4 compared to in late fall (P ≤ 0.10). Our study suggests that EEFs do not reduce N2O emissions from rainfed winter wheat crops, but a well-timed split application with a majority of fertilizer applied after winter can minimize N2O emissions.

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Assessing Seasonal Methane and Nitrous Oxide Emissions from Furrow-Irrigated Rice with Cover Crops

Agriculture ◽

10.3390/agriculture11030261 ◽

2021 ◽

Vol 11 (3) ◽

pp. 261

Author(s):

Sandhya Karki ◽

M. Arlene A. Adviento-Borbe ◽

Joseph H. Massey ◽

Michele L. Reba

Keyword(s):

Nitrous Oxide ◽

Cover Crops ◽

Management Practices ◽

Irrigation Management ◽

Nitrous Oxide Emissions ◽

N2o Emissions ◽

Irrigated Rice ◽

Cereal Rye ◽

Ch4 Emissions ◽

Ch4 And N2o

Improved irrigation management is identified as a potential mitigation option for methane (CH4) emissions from rice (Oryza sativa). Furrow-irrigated rice (FR), an alternative method to grow rice, is increasingly adopted in the Mid-South U.S. However, FR may provide a potential risk to yield performance and higher emissions of nitrous oxide (N2O). This study quantified the grain yields, CH4 and N2O emissions from three different water management practices in rice: multiple-inlet rice irrigation (MIRI), FR, and FR with cereal rye (Secale cereale) and barley (Hordeum vulgare) as preceding winter cover crops (FRCC). CH4 and N2O fluxes were measured from May to September 2019 using a static chamber technique. Grain yield from FR (11.8 Mg ha−1) and MIRI (12.0 Mg ha−1) was similar, and significantly higher than FRCC (8.5 Mg ha−1). FR and FRCC drastically reduced CH4 emissions compared to MIRI. Total seasonal CH4 emissions decreased in the order of 44 > 11 > 3 kg CH4-C ha−1 from MIRI, FR, and FRCC, respectively. Cumulative seasonal N2O emissions were low from MIRI (0.1 kg N2O-N ha−1) but significantly higher from FR (4.4 kg N2O-N ha−1) and FRCC (3.0 kg N2O-N ha−1). However, there was no net difference in global warming potential among FR, FRCC and MIRI. These results suggest that the increased N2O flux from furrow-irrigated rice may not greatly detract from the potential benefits that furrow-irrigation offers rice producers.

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