Soil N2O emissions from temperate cropland agroforestry and monoculture systems

2021 ◽  
Author(s):  
Guodong Shao ◽  
Guntars Martinson ◽  
Jie Luo ◽  
Xenia Bischel ◽  
Dan Niu ◽  
...  
Keyword(s):  
Western Europe ◽  
Temporal Dynamics ◽  
Pore Space ◽  
Tree Age ◽  
Soil Types ◽  
N2o Emissions ◽  
N Availability ◽  
Soil N ◽  
Mineral N ◽  
Climate Conditions

<p>Monoculture cropland is a major contributor to agriculture-related sources of N<sub>2</sub>O emission, a potent greenhouse gas and an agent of ozone depletion. Cropland agroforestry has the potential to minimize deleterious environmental impacts. Presently, there is no systematic comparison of soil N<sub>2</sub>O emission between cropland agroforestry (CAF) and monoculture systems (MC) in Western Europe. Our study aimed to (1) quantify the spatial-temporal dynamics of soil N<sub>2</sub>O fluxes, and (2) determine their soil controlling factors in CAF and MC. We selected three sites with different soil types (Phaeozem, Cambisol, and Arenosol) in Germany. Each site has paired CAF and MC (agroforestry sites consisted of 12-m wide tree row and 48-m wide crop row and were established in 2007, 2008 and 2019 in these soil types, respectively). In each management system at each site, we had four replicate plots. In the CAF, we conducted measurements in the tree row and within the crop row at 1 m, 7 m, and 24 m from the tree row. We measured soil N<sub>2</sub>O fluxes monthly over 2 years (March 2018‒February 2020) using static vented chambers method. Following gas sampling, we also measured soil temperature, water-filled pore space (WFPS), and mineral N (NH<sub>4</sub><sup>+</sup> and NO<sub>3</sub><sup>-</sup>) within the same day. Across all sites, soil moisture and N availability were major drivers of soil N<sub>2</sub>O fluxes. Both CAF and MC were net sources of soil N<sub>2</sub>O at all sites. At the site with Phaeozem soil, annual soil N<sub>2</sub>O emissions from CAF in both years (1.84 ± 0.35 and 1.17 ± 0.30 kg N ha<sup>−</sup><sup>1</sup> yr<sup>−</sup><sup>1</sup>) were greater than MC (0.89 ± 0.09 and 0.34 ± 0.05 kg N ha<sup>−</sup><sup>1</sup> yr<sup>−</sup><sup>1</sup>) (<em>P</em> = 0.03). At the site with Cambisol soil, annual soil N<sub>2</sub>O emission did not differ between MC (0.49 ± 0.07 kg N ha<sup>−</sup><sup>1</sup> yr<sup>−</sup><sup>1</sup>) and CAF (0.73 ± 0.13 kg N ha<sup>−</sup><sup>1</sup> yr<sup>−</sup><sup>1</sup>) in 2018/2019 (<em>P</em> = 0.20) whereas in 2019/2020 MC was 134% greater than CAF (2.92 ± 0.45 and 1.25 ± 0.08 kg N ha<sup>−</sup><sup>1</sup> yr<sup>−</sup><sup>1</sup>, respectively; <em>P</em> = 0.03). The inter-annual differences were largely related to crop types and to climate conditions. At the site with Arenosol soil, there was no difference between CAF and MC. Our results indicated that CAF may decrease, maintain and/or increase soil N<sub>2</sub>O emissions compared to MC depending on tree age, soil characteristics, management and precipitation.</p>

scholarly journals Regulation of N<sub>2</sub>O emissions from acid organic soil drained for agriculture: Effects of land use and season

2019 ◽  
Author(s):  
Arezoo Taghizadeh-Toosi ◽  
Lars Elsgaard ◽  
Tim J. Clough ◽  
Rodrigo Labouriau ◽  
Vibeke Ernstsen ◽  
...  
Keyword(s):  
Pyrite Oxidation ◽  
Acid Volatile Sulfide ◽  
Organic Soils ◽  
N2o Emissions ◽  
N Availability ◽  
Soil Mineral N ◽  
Soil Mineral ◽  
Mineral N ◽  
Total Reduction ◽  
Reduction Capacity

Abstract. Drained organic soils are extensively used for cereal and high-value cash crop production or as grazing land, but emissions of nitrous oxide (N2O) are enhanced by the drainage and cultivation. A study was conducted to investigate the regulation of N2O emissions in a raised bog area drained for agriculture. The area has been classified as potentially acid sulfate soil, and we hypothesised that pyrite oxidation was a potential driver of N2O emissions. Two sites with rotational grass, and two sites with a potato crop, were equipped for monitoring of N2O emissions, as well as sub-soil N2O concentrations at 5, 10, 20, 50 and 100 cm depth, during spring and autumn 2015. Precipitation, air and soil temperature, soil moisture, water table (WT) depth, and soil mineral N were recorded during weekly field campaigns. In late April and early September, intact cores were collected to 1 m depth at adjacent grassland and potato sites for analysis of soil properties, which included acid volatile sulfide (AVS) and chromium-reducible sulfur (CRS) to quantify, respectively, iron monosulfide (FeS) and pyrite (FeS2), as well as total reactive iron (TRFe) and nitrite (NO2−). Soil organic matter composition and total reduction capacity was also determined. The soil pH varied between 4.7 and 5.4. Equivalent soil gas phase concentrations of N2O ranged from around 10 µL L−1 at grassland sites to several hundred µL L−1 at potato sites, in accordance with lower soil mineral N concentrations at grassland sites. Total N2O emissions during 152–174 days were 3–6 kg N2O-N ha−1 for rotational grass, and 19–21 kg N2O-N ha−1 for potato sites. Statistical analyses by graphical models showed that soil N2O concentration in the capillary fringe was the strongest predictor for N2O emissions in spring, and for grassland sites also in the autumn. For potato sites in the autumn, nitrate (NO3−) availability in the top soil, together with temperature, were the main controls on N2O emissions. Pyrite oxidation coupled with NO3− reduction could not be dismissed as a source of N2O, but the total reduction capacity of the peat soil was much higher than explained by the FeS2 concentration. The concentrations of TRFe were also much higher than pyrite concentrations, and potentially chemodenitrification could have been a source of N2O during WT drawdown in spring. The N2O emissions associated with rapid soil wetting and WT rise in autumn were consistent with biological denitrification. Soil N availability and seasonal WT changes were important controls of N2O emissions.

scholarly journals Frequency Versus Quantity: Phenotypic Response of Two Wheat Varieties to Water and Nitrogen Variability

2021 ◽  
Author(s):  
Olivia H. Cousins ◽  
Trevor P. Garnett ◽  
Amanda Rasmussen ◽  
Sacha J. Mooney ◽  
Ronald J. Smernik ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Plant Growth ◽  
Carbon Allocation ◽  
N Uptake ◽  
N Availability ◽  
Soil N ◽  
High Moisture ◽  
Mineral N ◽  
Wheat Varieties ◽  
The Impact

AbstractDue to climate change, water availability will become increasingly variable, affecting nitrogen (N) availability. Therefore, we hypothesised watering frequency would have a greater impact on plant growth than quantity, affecting N availability, uptake and carbon allocation. We used a gravimetric platform, which measures the unit of volume per unit of time, to control soil moisture and precisely compare the impact of quantity and frequency of water under variable N levels. Two wheat genotypes (Kukri and Gladius) were used in a factorial glasshouse pot experiment, each with three N application rates (25, 75 and 150 mg N kg−1 soil) and five soil moisture regimes (changing water frequency or quantity). Previously documented drought tolerance, but high N use efficiency, of Gladius as compared to Kukri provides for potentially different responses to N and soil moisture content. Water use, biomass and soil N were measured. Both cultivars showed potential to adapt to variable watering, producing higher specific root lengths under low N coupled with reduced water and reduced watering frequency (48 h watering intervals), or wet/dry cycling. This affected mineral N uptake, with less soil N remaining under constant watering × high moisture, or 48 h watering intervals × high moisture. Soil N availability affected carbon allocation, demonstrated by both cultivars producing longer, deeper roots under low N. Reduced watering frequency decreased biomass more than reduced quantity for both cultivars. Less frequent watering had a more negative effect on plant growth compared to decreasing the quantity of water. Water variability resulted in differences in C allocation, with changes to root thickness even when root biomass remained the same across N treatments. The preferences identified in wheat for water consistency highlights an undeveloped opportunity for identifying root and shoot traits that may improve plant adaptability to moderate to extreme resource limitation, whilst potentially encouraging less water and nitrogen use.

Soil tests for predicting nitrogen supply for grassland under controlled environmental conditions

2014 ◽  
Vol 152 (S1) ◽  
pp. 82-95 ◽  
Author(s):  
N. T. MCDONALD ◽  
C. J. WATSON ◽  
R. J. LAUGHLIN ◽  
S. T. J. LALOR ◽  
J. GRANT ◽  
...  
Keyword(s):  
N Uptake ◽  
Soil Types ◽  
Soil N ◽  
Soil Tests ◽  
Mineral N ◽  
N Supply ◽  
Supply Potential ◽  
Growing Conditions ◽  
N Management ◽  
Over Time

SUMMARYMineralized soil nitrogen (N) is an important source of N for grassland production. Some soils can supply large quantities of plant-available N through mineralization of soil organic matter. Grass grown on such soils require less fertilizer N applications per unit yield. A reliable, accurate and user-friendly method to account for soil N supply potential across a large diversity of soils and growing conditions is needed to improve N management and N recommendations over time. In the current study, the effectiveness of chemical N tests and soil properties to predict soil N supply for grass uptake across 30 Irish soil types varying in N supply potential was investigated under controlled environmental conditions. The Illinois soil N test (ISNT) combined with soil C : N ratio provided a good estimate of soil N supply in soils with low residual mineral N. Total oxidized N (TON) had the largest impact on grass dry matter (DM) yield and N uptake across the 30 soil types, declining in its influence in later growth periods. This reflected the high initial mineral N levels in these soils, which declined over time. In the current study, a model with ISNT-N, C : N and TON (log TON) best explained variability in grass DM yield and N uptake. All three rapid chemical soil tests could be performed routinely on field samples to provide an estimate of soil N supply prior to making N fertilizer application decisions. It can be concluded that these soil tests, through their assessment of soil N supply potential, can be effective tools for N management on grassland; however, field studies are needed to evaluate this under more diverse growing conditions.

scholarly journals Soil N availability, rather than N deposition, controls indirect N2O emissions

2016 ◽  
Vol 95 ◽  
pp. 288-298 ◽  
Author(s):  
M.R. Redding ◽  
P.R. Shorten ◽  
R. Lewis ◽  
C. Pratt ◽  
C. Paungfoo-Lonhienne ◽  
...  
Keyword(s):  
N Deposition ◽  
N2o Emissions ◽  
N Availability ◽  
Soil N ◽  
Soil N Availability

scholarly journals The Exudation of Surplus Products Links Plant Functional Traits and Plant-Microbial Stoichiometry

Land ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 840
Author(s):  
Julian Cardenas ◽  
Fernando Santa ◽  
Eva Kaštovská
Keyword(s):  
Plant Growth ◽  
Functional Traits ◽  
Plant Functional Traits ◽  
Ammonium Uptake ◽  
Grass Species ◽  
N Availability ◽  
Soil N ◽  
Mineral N ◽  
C:N:P Stoichiometry ◽  
Soil N Availability

The rhizosphere is a hot spot of soil microbial activity and is largely fed by root exudation. The carbon (C) exudation flux, coupled with plant growth, is considered a strategy of plants to facilitate nutrient uptake. C exudation is accompanied by a release of nutrients. Nitrogen (N) and phosphorus (P) co-limit the productivity of the plant-microbial system. Therefore, the C:N:P stoichiometry of exudates should be linked to plant nutrient economies, plant functional traits (PFT) and soil nutrient availability. We aimed to identify the strongest links in C:N:P stoichiometry among all rhizosphere components. A total of eight grass species (from conservative to exploitative) were grown in pots under two different soil C:nutrient conditions for a month. As a result, a wide gradient of plant–microbial–soil interactions were created. A total of 43 variables of plants, exudates, microbial and soil C:N:P stoichiometry, and PFTs were evaluated. The variables were merged into four groups in a network analysis, allowing us to identify the strongest connections among the variables and the biological meaning of these groups. The plant–soil interactions were shaped by soil N availability. Faster-growing plants were associated with lower amounts of mineral N (and P) in the soil solution, inducing a stronger competition for N with microorganisms in the rhizosphere compared to slower-growing plants. The plants responded by enhancing their N use efficiency and root:shoot ratio, and they reduced N losses via exudation. Root growth was supported either by reallocated foliar reserves or by enhanced ammonium uptake, which connected the specific leaf area (SLA) to the mineral N availability in the soil. Rapid plant growth enhanced the exudation flux. The exudates were rich in C and P relative to N compounds and served to release surplus metabolic products. The exudate C:N:P stoichiometry and soil N availability combined to shape the microbial stoichiometry, and N and P mining. In conclusion, the exudate flux and its C:N:P stoichiometry reflected the plant growth rate and nutrient constraints with a high degree of reliability. Furthermore, it mediated the plant–microbial interactions in the rhizosphere.

Soil-N cycling in temperate alley cropping agroforestry and monoculture croplands

2021 ◽  
Author(s):  
Xenia Bischel ◽  
Marife D. Corre ◽  
Marcus Schmidt ◽  
Edzo Veldkamp
Keyword(s):  
Environmental Effects ◽  
Western Europe ◽  
Management Practices ◽  
Alley Cropping ◽  
Pore Space ◽  
Agroforestry Systems ◽  
N Cycling ◽  
Soil N ◽  
Soil C ◽  
Gene Abundance

&lt;p&gt;Monoculture croplands are commonly associated with deleterious environmental effects due to high fertilization rates. Agroforestry (alternate alleys of trees and crops or alley cropping) has the potential to mitigate the negative environmental effects from agriculture. Understanding the soil-N cycling aids in assessing how the soil function of nutrient cycling is impacted when monoculture system is converted into agroforestry. Currently, there is no systematic comparison in soil-N cycling rates between monoculture and agroforestry croplands in Western Europe. Our study aimed to investigate gross rates of soil-N cycling between agroforestry and monoculture croplands. We measured gross rates of soil-N cycling, using 15N isotopic pool dilution in May-June 2017, at three sites in Germany (Wendhausen, Dornburg, and Forst with Vertic Cambisol, Calcaric Phaeozem, Gleyic Cambisol soils, respectively); each site has paired monoculture and agroforestry systems (established in 2008, 2007, and 2010 at the respective sites). In each management system at each site, we had four replicate plots; for agroforestry system, we conducted measurements in the tree row and within the crop row at 1 m, 4 m, and 7 m from the tree row. The crop management practices in agroforestry crop row and monoculture were the same at each site.&lt;/p&gt;&lt;p&gt;For gross rates of ammonium cycling, differences were observed between agroforestry tree row, crop row and monoculture at the site with Vertic Cambisol soil. Higher gross N mineralization rates were observed in monoculture than agroforestry tree row whilst agroforestry tree row exhibited higher gross NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt; immobilization rates than agroforestry crop row (P &lt; 0.02). This was correlated to higher soil C/N ratio and higher water-filled pore space in the tree row. Tree rows also tend to have higher microbial biomass at all sites. Gross rates of nitrate cycling were higher in the tree row than in the crop row and monoculture at the site with Calcaric Phaeozem soil. This showed a similar pattern with the gene abundance of ammonium oxidizing archeae (AOA), supporting a niche differentiation of AOA by utilizing ammonium mineralized from soil organic matter rather than from fertilizer source. At the site with Vertic Cambisol soil, dissimilatory nitrate reduction to ammonium was very high in the tree row. These changes in soil-N cycling and AOA gene abundance in the tree rows suggest that trees in sites with older agroforestry systems had enhanced the cycling of N in the soil.&lt;/p&gt;

Understanding the Complex Interaction Between Soil N Availability and Soil C Dynamics Under Changing Climate Conditions 1

2018 ◽  
pp. 337-348 ◽  
Author(s):  
Pratap Srivastava ◽  
Rishikesh Singh ◽  
Sachchidanand Tripathi ◽  
Hema Singh ◽  
Akhilesh Singh Raghubanshi
Keyword(s):  
Complex Interaction ◽  
N Availability ◽  
Soil N ◽  
Soil C ◽  
Climate Conditions ◽  
Soil N Availability ◽  
Changing Climate ◽  
C Dynamics

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
Keyword(s):  
Nitrous Oxide ◽  
Physical Properties ◽  
Water Content ◽  
Soil Physical Properties ◽  
Atmospheric Composition ◽  
Nitrous Oxide Emissions ◽  
N2o Emissions ◽  
N Availability ◽  
Soil N ◽  
Anhydrous Ammonia

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

scholarly journals Influence of stubble quality and degree of soil-stubble contact on N2O emission

2017 ◽  
Vol 63 (No. 7) ◽  
pp. 289-294
Author(s):  
Cosentino Vanina Rosa Noemí ◽  
Minervini Mariana G ◽  
Taboada Miguel A
Keyword(s):  
Pore Space ◽  
Threshold Value ◽  
Soil N ◽  
Mineral N ◽  
Randomized Design ◽  
N Release ◽  
Controlling Variables ◽  
Completely Randomized Design ◽  
Closed Chambers ◽  
Residue Position

The organic residue position and C/N ratio regulate decomposition rate and, therefore, nitrogen (N) release to the soil. The N<sub>2</sub>O emission from soil is produced by nitrification and denitrification processes. These processes are affected by the mineral N concentration, water filled pore space (WFPS) and soil temperature. The N<sub>2</sub>O emission from soils covered by corn and soybean residues has been little studied so far. The aim of the present study was to evaluate the C/N ratio of corn and soybean residues and their contact degree with the soil on soil N<sub>2</sub>O emissions. A greenhouse experiment was conducted with a completely randomized design and N<sub>2</sub>O emission was determined using closed chambers. The N<sub>2</sub>O emissions were affected by the residue position and not by its origin (soybean = corn). Treatments with residue on the surface had the highest N<sub>2</sub>O emissions at the beginning of the trial, while residue incorporation showed constant values of N<sub>2</sub>O emission during the experiment. Soil N<sub>2</sub>O emissions were explained by two controlling variables: the WFPS and the N-NO<sub>3</sub><sup>–</sup> soil concentration. The WFPS separated the emission values of N<sub>2</sub>O into two groups (threshold value near 77% WFPS). When the WFPS exceeded the threshold value, the emissions of N<sub>2</sub>O were partially explained by the concentration of N-NO<sub>3</sub><sup>–</sup> soil.

Global maps of current and future nitrogen mineralization

2020 ◽  
Author(s):  
Julia Maschler ◽  
Daniel S. Maynard ◽  
Devin Routh ◽  
Johan van den Hoogen ◽  
Zhaolei Li ◽  
...  
Keyword(s):  
Nitrogen Mineralization ◽  
Climate Models ◽  
Net Primary Productivity ◽  
Plant Biomass ◽  
Global Scale ◽  
N Availability ◽  
Soil N ◽  
Climate Conditions ◽  
Tropical Regions ◽  
Terrestrial Carbon Sequestration

&lt;p&gt;Soil nitrogen is a prominent determinant of plant growth, with nitrogen (N) availability being a key driver of terrestrial carbon sequestration. The local availability of soil N is thus crucial to our understanding of broad-scale trends in soil fertility, productivity, and carbon dynamics. Here, we provide global, high-resolution maps of current and future (2050) potential net nitrogen mineralization (N-min), revealing global patterns in soil N availability. Highest mineralization rates are found in warm and moist tropical regions, leading to a strong latitudinal gradient in N-min. We observed a positive correlation of N-min rates with human population density and net primary productivity. Projected climate conditions for 2050 suggest that N availability will further decrease in areas of low N availability and increase in areas of high N availability, thereby intensifying current global trends. These results shed light on the core processes governing productivity at a global scale, providing an opportunity to improve the accuracy of plant biomass and climate models.&lt;/p&gt;

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