Does agroecosystem model improvement increase simulation accuracy for agricultural N2O emissions?

Unfortunately an incorrect version of Figure 4 appears on p517 of this paper; the correct version is as printed below. A sentence (“Increased N2O emissions…. Conversely”) should then also be deleted from the corresponding paragraph of the main text as printed on pp516–517; the correct version of this paragraph is also given below. The authors and publisher regret any confusion or inconvenience this may have caused.

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Biochar and urease inhibitor mitigate NH3 and N2O emissions and improve wheat yield in a urea fertilized alkaline soil

Scientific Reports ◽

10.1038/s41598-021-96771-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Khadim Dawar ◽

Shah Fahad ◽

M. M. R. Jahangir ◽

Iqbal Munir ◽

Syed Sartaj Alam ◽

...

Keyword(s):

Nitrous Oxide ◽

Grain Yield ◽

Block Design ◽

N Uptake ◽

Nitrous Oxide Emissions ◽

N2o Emissions ◽

Urease Inhibitor ◽

Alkaline Soil ◽

Total N ◽

N Assimilation

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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Higher Sensitivity of Soil Microbial Network Than Community Structure under Acid Rain

Microorganisms ◽

10.3390/microorganisms9010118 ◽

2021 ◽

Vol 9 (1) ◽

pp. 118

Author(s):

Ziqiang Liu ◽

Hui Wei ◽

Jiaen Zhang ◽

Muhammad Saleem ◽

Yanan He ◽

...

Keyword(s):

Community Structure ◽

Acid Rain ◽

Natural Soil ◽

Available Phosphorus ◽

Global Changes ◽

N2o Emissions ◽

Ammonia Oxidizing Bacteria ◽

Soil Core ◽

N Cycle ◽

Microbial Network

Acid rain (AR), as a global environmental threat, has profoundly adverse effects on natural soil ecosystems. Microorganisms involved in the nitrogen (N) cycle regulate the global N balance and climate stabilization, but little is known whether and how AR influences the structure and complexity of these microbial communities. Herein, we conducted an intact soil core experiment by manipulating the acidity of simulated rain (pH 7.5 (control, CK) vs. pH 4.0 (AR)) in subtropical agricultural soil, to reveal the differences in the structure and complexity of soil nitrifying and denitrifying microbiota using Illumina amplicon sequencing of functional genes (amoA, nirS, and nosZ). Networks of ammonia-oxidizing archaea (AOA) and nirS-carrying denitrifiers in AR treatment were less complex with fewer nodes and lower connectivity, while network of nosZ-carrying denitrifiers in AR treatment had higher complexity and connectivity relative to CK. Supporting this, AR reduced the abundance of keystone taxa in networks of AOA and nirS-carrying denitrifiers, but increased the abundance of keystone taxa in nosZ-carrying denitrifiers network. However, AR did not alter the community structure of AOA, ammonia-oxidizing bacteria (AOB), nirS-, and nosZ-carrying denitrifiers. Moreover, AR did not change soil N2O emissions during the experimental period. AOB community structure significantly correlated with content of soil available phosphorus (P), while the community structures of nirS- and nosZ-carrying denitrifiers both correlated with soil pH and available P content. Soil N2O emission was mainly driven by the nirS-carrying denitrifiers. Our results present new perspective on the impacts of AR on soil N-cycle microbial network complexity and keystone taxa in the context of global changes.

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Irrigation Scheduling with Soil Gas Diffusivity as a Decision Tool to Mitigate N2O Emissions from a Urine-Affected Pasture

Agriculture ◽

10.3390/agriculture11050443 ◽

2021 ◽

Vol 11 (5) ◽

pp. 443

Author(s):

Camille Rousset ◽

Timothy J. Clough ◽

Peter R. Grace ◽

David W. Rowlings ◽

Clemens Scheer

Keyword(s):

Irrigation Management ◽

Irrigation Treatment ◽

Irrigation Scheduling ◽

Soil Gas ◽

N2o Emissions ◽

Irrigation Frequency ◽

Water Demands ◽

Gas Diffusivity ◽

Matter Production ◽

Access To Water

Pastures require year-round access to water and in some locations rely on irrigation during dry periods. Currently, there is a dearth of knowledge about the potential for using irrigation to mitigate N2O emissions. This study aimed to mitigate N2O losses from intensely managed pastures by adjusting irrigation frequency using soil gas diffusivity (Dp/Do) thresholds. Two irrigation regimes were compared; a standard irrigation treatment based on farmer practice (15 mm applied every 3 days) versus an optimised irrigation treatment where irrigation was applied when soil Dp/Do was ≈0.033 (equivalent to 50% of plant available water). Cow urine was applied at a rate of 700 kg N ha−1 to simulate a ruminant urine deposition event. In addition to N2O fluxes, soil moisture content was monitored hourly, Dp/Do was modelled, and pasture dry matter production was measured. Standard irrigation practices resulted in higher (p = 0.09) cumulative N2O emissions than the optimised irrigation treatment. Pasture growth rates under treatments did not differ. Denitrification during re-wetting events (irrigation and rain) contributed to soil N2O emissions. These results warrant further modelling of irrigation management as a mitigation option for N2O emissions from pasture soils, based on Dp/Do thresholds, rainfall, plant water demands and evapotranspiration.

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Nitrapyrin coupled with organic amendment mitigates N2O emissions by inhibiting different ammonia oxidizers in alkaline and acidic soils

Applied Soil Ecology ◽

10.1016/j.apsoil.2021.104062 ◽

2021 ◽

Vol 166 ◽

pp. 104062

Author(s):

Rui Tao ◽

Xiran Zhao ◽

Xiaoliang Wu ◽

Baowei Hu ◽

Kollie B. Vanyanbah ◽

...

Keyword(s):

Organic Amendment ◽

N2o Emissions ◽

Ammonia Oxidizers ◽

Acidic Soils

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Effects of Organic Fertilizers on the Soil Microorganisms Responsible for N2O Emissions: A Review

Microorganisms ◽

10.3390/microorganisms9050983 ◽

2021 ◽

Vol 9 (5) ◽

pp. 983

Author(s):

Cristina Lazcano ◽

Xia Zhu-Barker ◽

Charlotte Decock

Keyword(s):

Community Structure ◽

Microbial Community ◽

Best Management Practices ◽

Management Practices ◽

Organic Fertilizers ◽

N2o Emissions ◽

Soil C ◽

Best Management ◽

C Stocks ◽

Denitrifying Microorganisms

The use of organic fertilizers constitutes a sustainable strategy to recycle nutrients, increase soil carbon (C) stocks and mitigate climate change. Yet, this depends largely on balance between soil C sequestration and the emissions of the potent greenhouse gas nitrous oxide (N2O). Organic fertilizers strongly influence the microbial processes leading to the release of N2O. The magnitude and pattern of N2O emissions are different from the emissions observed from inorganic fertilizers and difficult to predict, which hinders developing best management practices specific to organic fertilizers. Currently, we lack a comprehensive evaluation of the effects of OFs on the function and structure of the N cycling microbial communities. Focusing on animal manures, here we provide an overview of the effects of these organic fertilizers on the community structure and function of nitrifying and denitrifying microorganisms in upland soils. Unprocessed manure with high moisture, high available nitrogen (N) and C content can shift the structure of the microbial community, increasing the abundance and activity of nitrifying and denitrifying microorganisms. Processed manure, such as digestate, compost, vermicompost and biochar, can also stimulate nitrifying and denitrifying microorganisms, although the effects on the soil microbial community structure are different, and N2O emissions are comparatively lower than raw manure. We propose a framework of best management practices to minimize the negative environmental impacts of organic fertilizers and maximize their benefits in improving soil health and sustaining food production systems. Long-term application of composted manure and the buildup of soil C stocks may contribute to N retention as microbial or stabilized organic N in the soil while increasing the abundance of denitrifying microorganisms and thus reduce the emissions of N2O by favoring the completion of denitrification to produce dinitrogen gas. Future research using multi-omics approaches can be used to establish key biochemical pathways and microbial taxa responsible for N2O production under organic fertilization.

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