Accounting for carbon exchanges in a semiarid oak savanna (dehesa).

2021 ◽  
Author(s):  
Ana Andreu ◽  
Elisabet Carpintero ◽  
Pedro Gómez-Giraldez ◽  
Maria P. González-Dugo
Keyword(s):  
Ghg Emissions ◽  
Negative Evaluation ◽  
System Structure ◽  
Economic Production ◽  
Tree Layer ◽  
Agrosilvopastoral System ◽  
Flux Measurements ◽  
Scattered Trees ◽  
Extensive Farming ◽  
Ch4 And N2o

<p>Semiarid oak savannas (grasslands with scattered trees), partially covered, subject to regular droughts, grazing, and high levels of solar radiation, are nonetheless, typically carbon sinks regarding CO2. However, dehesas are a productive system, a trait shared with other savannas, and they are shaped by their uses for economic production. One of its multiple uses, livestock extensive farming, key to its economic profitability and to the preservation of the agrosilvopastoral system structure, modifies the Greenhouse gas (GHG) balance by adding a significant amount of CH4 and N2O into the cycle. Recent reports and publications have evaluated and compared different types of livestock management within the context of climate change. GHG emissions, extensive use of the soil resource, or the introduction of nitrogen into the system, are some of the generated effects that cause a negative evaluation of extensive farming. Nevertheless, the importance of this sector, given its extension and impact on production and rural development, demands a more rigorous evaluation. It is necessary to precisely account for the fluxes in their totality (including the CO2 sink effect) and the relationships between them. Currently, there are few studies that determine the GHG balance of dehesas, and they are mainly centred on CO2 fluxes without integrating the influence of livestock, or in meadows without a tree layer (which changes the CO2 balance). The net global warming potential of dehesas is unknown, given that very few direct and long-term flux measurements have been taken on them. In this work, CO2 and H2O fluxes from an eddy covariance tower located in an Andalusian dehesa were processed (standard corrections), filtered and homogenized, including filling gaps using artificial neural networks. We calculated the annual CO2 budget since 2015, to assess the sink/source nature of the area. In a modeling exercise to be able to close the carbon cycle, we estimated CH4 and N2O depending on the number of livestock present in the area by season/year, evaluating the tipping point.</p>

scholarly journals PSXI-4 Composting management to reduce greenhouse gas and ammonia emissions from feedlot manure

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 388-388
Author(s):  
Maria A Donnay ◽  
Jennifer J Michal ◽  
GeorgiaLee J Aksdal ◽  
Brian K Lamb ◽  
Kristen A Johnson
Keyword(s):  
Greenhouse Gas ◽  
Ghg Emissions ◽  
Fine Tuning ◽  
N2o Emissions ◽  
Ammonia Emissions ◽  
Ambient Temperatures ◽  
Wind Speeds ◽  
Different Seasons ◽  
Flux Measurements ◽  
Ch4 And N2o

Abstract Management of livestock manure may recycle nutrients and decrease greenhouse gas (GHG) and ammonia (NH3) emissions. The objectives were to ascertain effects of environmental conditions and turning on methane (CH4), nitrous oxide (N2O), and NH3 emissions and if treatment with 8.5 g of dicyandiamide (DCD), a denitrification agent, altered GHG emissions. Manure and bedding were collected from feedlot pens and used to construct 3 piles (~1.9 m3 volume) each in winter (WI) and spring (SP). WI piles were turned once, and SP piles were turned twice. Methane, N2O, and NH3 emissions were collected. Methane and N2O flux measurements were collected from SP piles using a static chamber (3.7m L x 2.2m W x 0.9m H). Initial dry matter and nitrogen contents were 33.2 and 30.0% and 20.1 and 17.7 g/kg in WI and SP piles, respectively. Average ambient temperatures and wind speeds were 0.3oC and 10.7oC and 1.76 m/s and 1.97 m/s during WI and SP, respectively. Internal temperatures reached 51±3.9oC on d 4–11 and gradually decreased. Normalized CH4 averaged 2.19 mg٠s٠m-4 and N2O emissions averaged 0.84 mg٠s٠m-4, and were not different between the WI and SP piles. Turning did not affect CH4 emissions from WI piles, but were 55% greater (P < 0.05) when SP piles were turned a second time. Emissions of N2O increased 51% when WI and SP piles were turned (P < 0.05). Ammonia emissions were 83.5% greater from WI piles due to their higher initial concentrations of NH4+-N (2.21 vs. 1.11 g/kg; P < 0.05). Turning did not influence CH4 and N2O fluxes. Addition of DCD at pile formation appears to decrease N2O emissions and fluxes 3 and 10 d later. Turning management and season impacted overall CH4, N2O, and NH3 emissions. Fine-tuning manure handling and management during different seasons may effectively reduce GHG and NH3 emissions.

scholarly journals Greenhouse gas balance of cropland conversion to bioenergy poplar short-rotation coppice

2016 ◽  
Vol 13 (1) ◽  
pp. 95-113 ◽  
Author(s):  
S. Sabbatini ◽  
N. Arriga ◽  
T. Bertolini ◽  
S. Castaldi ◽  
T. Chiti ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Arable Land ◽  
Hybrid Poplar ◽  
Ghg Emissions ◽  
Net Ecosystem Exchange ◽  
Short Rotation Coppice ◽  
Co2 Uptake ◽  
Greenhouse Gas Balance ◽  
Short Rotation ◽  
Ch4 And N2o

Abstract. The production of bioenergy in Europe is one of the strategies conceived to reduce greenhouse gas (GHG) emissions. The suitability of the land use change from a cropland (REF site) to a short-rotation coppice plantation of hybrid poplar (SRC site) was investigated by comparing the GHG budgets of these two systems over 24 months in Viterbo, Italy. This period corresponded to a single rotation of the SRC site. The REF site was a crop rotation between grassland and winter wheat, i.e. the same management of the SRC site before the conversion to short-rotation coppice. Eddy covariance measurements were carried out to quantify the net ecosystem exchange of CO2 (FCO2), whereas chambers were used to measure N2O and CH4 emissions from soil. The measurements began 2 years after the conversion of arable land to SRC so that an older poplar plantation was used to estimate the soil organic carbon (SOC) loss due to SRC establishment and to estimate SOC recovery over time. Emissions from tractors and from production and transport of agricultural inputs (FMAN) were modelled. A GHG emission offset, due to the substitution of natural gas with SRC biomass, was credited to the GHG budget of the SRC site. Emissions generated by the use of biomass (FEXP) were also considered. Suitability was finally assessed by comparing the GHG budgets of the two sites. CO2 uptake was 3512 ± 224 g CO2 m−2 at the SRC site in 2 years, and 1838 ± 107 g CO2 m−2 at the REF site. FEXP was equal to 1858 ± 240 g CO2 m−2 at the REF site, thus basically compensating for FCO2, while it was 1118 ± 521 g CO2 m−2 at the SRC site. The SRC site could offset 379.7 ± 175.1 g CO2eq m−2 from fossil fuel displacement. Soil CH4 and N2O fluxes were negligible. FMAN made up 2 and 4 % in the GHG budgets of SRC and REF sites respectively, while the SOC loss was 455 ± 524 g CO2 m−2 in 2 years. Overall, the REF site was close to neutrality from a GHG perspective (156 ± 264 g CO2eq m−2), while the SRC site was a net sink of 2202 ± 792 g CO2eq m−2. In conclusion the experiment led to a positive evaluation from a GHG viewpoint of the conversion of cropland to bioenergy SRC.

scholarly journals Greenhouse gas flux measurements in a forestry-drained peatland indicate a large carbon sink

2011 ◽  
Vol 8 (11) ◽  
pp. 3203-3218 ◽  
Author(s):  
A. Lohila ◽  
K. Minkkinen ◽  
M. Aurela ◽  
J.-P. Tuovinen ◽  
T. Penttilä ◽  
...  
Keyword(s):  
Carbon Sink ◽  
Accumulation Rate ◽  
Peat Soil ◽  
Net Ecosystem Exchange ◽  
Flux Measurement ◽  
Co2 Exchange ◽  
Co2 Uptake ◽  
Flux Measurements ◽  
Ch4 And N2o ◽  
Carbon Dioxide Co2

Abstract. Drainage for forestry purposes increases the depth of the oxic peat layer and leads to increased growth of shrubs and trees. Concurrently, the production and uptake of the greenhouse gases carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) change: due to the accelerated decomposition of peat in the presence of oxygen, drained peatlands are generally considered to lose peat carbon (C). We measured CO2 exchange with the eddy covariance (EC) method above a drained nutrient-poor peatland forest in southern Finland for 16 months in 2004–2005. The site, classified as a dwarf-shrub pine bog, had been ditched about 35 years earlier. CH4 and N2O fluxes were measured at 2–5-week intervals with the chamber technique. Drainage had resulted in a relatively little change in the water table level, being on average 40 cm below the ground in 2005. The annual net ecosystem exchange was −870 ± 100 g CO2 m−2 yr−1 in the calendar year 2005, indicating net CO2 uptake from the atmosphere. The site was a small sink of CH4 (−0.12 g CH4 m−2 yr−1) and a small source of N2O (0.10 g N2O m−2 yr−1). Photosynthesis was detected throughout the year when the air temperature exceeded −3 °C. As the annual accumulation of C in the above and below ground tree biomass (175 ± 35 g C m−2) was significantly lower than the accumulation observed by the flux measurement (240 ± 30 g C m−2), about 65 g C m−2 yr−1 was likely to have accumulated as organic matter into the peat soil. This is a higher average accumulation rate than previously reported for natural northern peatlands, and the first time C accumulation has been shown by EC measurements to occur in a forestry-drained peatland. Our results suggest that forestry-drainage may significantly increase the CO2 uptake rate of nutrient-poor peatland ecosystems.

scholarly journals The European land and inland water CO<sub>2</sub>, CO, CH<sub>4</sub> and N<sub>2</sub>O balance between 2001 and 2005

2012 ◽  
Vol 9 (8) ◽  
pp. 3357-3380 ◽  
Author(s):  
S. Luyssaert ◽  
G. Abril ◽  
R. Andres ◽  
D. Bastviken ◽  
V. Bellassen ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Aquatic Ecosystems ◽  
Terrestrial Ecosystems ◽  
C Sequestration ◽  
Sink Strength ◽  
Terrestrial Carbon Sequestration ◽  
Net Uptake ◽  
Flux Measurements ◽  
Ch4 And N2o ◽  
Constraint Approach

Abstract. Globally, terrestrial ecosystems have absorbed about 30% of anthropogenic greenhouse gas emissions over the period 2000–2007 and inter-hemispheric gradients indicate that a significant fraction of terrestrial carbon sequestration must be north of the Equator. We present a compilation of the CO2, CO, CH4 and N2O balances of Europe following a dual constraint approach in which (1) a land-based balance derived mainly from ecosystem carbon inventories and (2) a land-based balance derived from flux measurements are compared to (3) the atmospheric data-based balance derived from inversions constrained by measurements of atmospheric GHG (greenhouse gas) concentrations. Good agreement between the GHG balances based on fluxes (1294 ± 545 Tg C in CO2-eq yr−1), inventories (1299 ± 200 Tg C in CO2-eq yr−1) and inversions (1210 ± 405 Tg C in CO2-eq yr−1) increases our confidence that the processes underlying the European GHG budget are well understood and reasonably sampled. However, the uncertainty remains large and largely lacks formal estimates. Given that European net land to atmosphere exchanges are determined by a few dominant fluxes, the uncertainty of these key components needs to be formally estimated before efforts could be made to reduce the overall uncertainty. The net land-to-atmosphere flux is a net source for CO2, CO, CH4 and N2O, because the anthropogenic emissions by far exceed the biogenic sink strength. The dual-constraint approach confirmed that the European biogenic sink removes as much as 205 ± 72 Tg C yr−1 from fossil fuel burning from the atmosphere. However, This C is being sequestered in both terrestrial and inland aquatic ecosystems. If the C-cost for ecosystem management is taken into account, the net uptake of ecosystems is estimated to decrease by 45% but still indicates substantial C-sequestration. However, when the balance is extended from CO2 towards the main GHGs, C-uptake by terrestrial and aquatic ecosystems is offset by emissions of non-CO2 GHGs. As such, the European ecosystems are unlikely to contribute to mitigating the effects of climate change.

Processes and magnitude of CO2, CH4, and N2O fluxes from liming of Australian acidic soils: a review

Soil Research ◽  
2009 ◽  
Vol 47 (8) ◽  
pp. 747 ◽  
Author(s):  
K. L. Page ◽  
D. E. Allen ◽  
R. C. Dalal ◽  
W. Slattery
Keyword(s):  
Agricultural Soils ◽  
Ghg Emissions ◽  
Primary Objective ◽  
Carbon Accounting ◽  
Accounting System ◽  
Biological Processes ◽  
Recent Approach ◽  
Tier 1 ◽  
Ch4 And N2o ◽  
Induced Changes

Increases in soil acidification have led to large increases in the application of aglime to Australian agricultural soils. The addition of aglime has the potential to increase greenhouse gas (GHG) emissions due to the release of CO2 during the chemical dissolution of aglime and due to pH-induced changes to soil biological processes. Currently, Australia’s GHG accounting system assumes that all the carbon contained in aglime is released to the atmosphere during dissolution in accordance with the Tier 1 methodology of the IPCC. However, a recent approach by TO West and AC McBride has questioned this assumption, hypothesising that a proportion of the carbon from riverine-transported aglime may be sequestered in seawater. In addition, there is presently no capacity within Australia’s carbon accounting system to quantify changes to GHG emissions from lime-induced changes to soil biological processes. Therefore, the primary objective of this review was to examine the chemical and biological processes occurring during the application of aglime and the subsequent fluxes in CO2, N2O, and CH4 from soil, with particular reference to the Australian environment. Estimates for CO2 emissions from aglime application in Australia using the contrasting methodologies of the IPCC and West and McBride were compared. Using the methodology of the IPCC it was determined that from the aglime applied in Australia in 2002, 0.995 Tg of CO2 would have been emitted, whereas this figure was reduced to 0.659–0.860 Tg of CO2 using the methodology of West and McBride. However, the accuracy of these estimates is currently limited by poor understanding of the manner in which aglime moves within the Australian landscapes. In addition, there are only a very small number of Australian studies that have examined the effect of aglime on GHG emissions due to changes in soil biological processes, limiting the ability of Australian modellers to accurately incorporate these processes within the carbon accounting system.

scholarly journals Reviews and syntheses: Greenhouse gas exchange data from drained organic forest soils – a review of current approaches and recommendations for future research

2019 ◽  
Vol 16 (23) ◽  
pp. 4687-4703 ◽  
Author(s):  
Jyrki Jauhiainen ◽  
Jukka Alm ◽  
Brynhildur Bjarnadottir ◽  
Ingeborg Callesen ◽  
Jesper R. Christiansen ◽  
...  
Keyword(s):  
Forest Soils ◽  
Ghg Emissions ◽  
Emission Factors ◽  
Environmental Data ◽  
Temperate Climate ◽  
Future Research ◽  
Organic Soils ◽  
Climate Zones ◽  
Ch4 And N2o ◽  
Carbon Dioxide Co2

Abstract. Drained organic forest soils in boreal and temperate climate zones are believed to be significant sources of the greenhouse gases (GHGs) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), but the annual fluxes are still highly uncertain. Drained organic soils exemplify systems where many studies are still carried out with relatively small resources, several methodologies and manually operated systems, which further involve different options for the detailed design of the measurement and data analysis protocols for deriving the annual flux. It would be beneficial to set certain guidelines for how to measure and report the data, so that data from individual studies could also be used in synthesis work based on data collation and modelling. Such synthesis work is necessary for deciphering general patterns and trends related to, e.g., site types, climate, and management, and the development of corresponding emission factors, i.e. estimates of the net annual soil GHG emission and removal, which can be used in GHG inventories. Development of specific emission factors also sets prerequisites for the background or environmental data to be reported in individual studies. We argue that wide applicability greatly increases the value of individual studies. An overall objective of this paper is to support future monitoring campaigns in obtaining high-value data. We analysed peer-reviewed publications presenting CO2, CH4 and N2O flux data for drained organic forest soils in boreal and temperate climate zones, focusing on data that have been used, or have the potential to be used, for estimating net annual soil GHG emissions and removals. We evaluated the methods used in data collection and identified major gaps in background or environmental data. Based on these, we formulated recommendations for future research.

scholarly journals Effects of Forage Rice Cultivation on Carbon and Greenhouse Gas Balances in a Rice Paddy Field

Atmosphere ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 504 ◽  
Author(s):  
Fumiaki Takakai ◽  
Masahiro Kobayashi ◽  
Takashi Sato ◽  
Kentaro Yasuda ◽  
Yoshihiro Kaneta
Keyword(s):  
Greenhouse Gas ◽  
Paddy Field ◽  
Net Primary Production ◽  
Ghg Emissions ◽  
Co2 Flux ◽  
Rice Paddy ◽  
Bare Soil ◽  
Rice Cultivation ◽  
Forage Rice ◽  
Ch4 And N2o

The effects of conversion from staple rice to forage rice on carbon and greenhouse gas (GHG) balances in a paddy field were evaluated. A staple rice plot without the application of livestock manure compost (LMC, S − M plot) and forage rice plots with and without the application of LMC, derived mainly from cattle (2 kg−FW m−2, F + M and F − M plots, respectively), were established. CH4 and N2O fluxes and CO2 flux from a bare soil plot for organic matter decomposition (OMD) were measured. The carbon budget was calculated by subtracting the OMD, CH4 emission, and harvested grain and straw (forage rice only) from the net primary production and LMC. The net GHG balance was calculated by integrating them as CO2 equivalents. There were no significant differences in GHG flux among the plots. Compared to the carbon loss in the S − M plot, the loss increased by harvesting straw and was mitigated by LMC application. The net GHG emission in the F + M plot was significantly lower than that in other plots (1.78 and 2.63−2.77 kg CO2-eq m−2 year−1, respectively). There is a possibility that GHG emissions could be suppressed by forage rice cultivation with the application of LMC.

scholarly journals Methane and nitrous oxide sources and emissions in a subtropical freshwater reservoir, south east Queensland, Australia

2013 ◽  
Vol 10 (12) ◽  
pp. 19485-19508
Author(s):  
K. Sturm ◽  
Z. Yuan ◽  
B. Gibbes ◽  
A. Grinham
Keyword(s):  
Nitrous Oxide ◽  
Water Column ◽  
Water Flux ◽  
N2o Emissions ◽  
Pore Waters ◽  
Flux Measurements ◽  
Study Support ◽  
Ch4 And N2o ◽  
Diffusive Fluxes ◽  
Freshwater Reservoir

Abstract. Reservoirs have been identified as an important source of non-CO2 greenhouse gases, especially methane (CH4). This study investigates CH4 and nitrous oxide (N2O) sources and emissions in a subtropical freshwater reservoir Gold Creek Dam, Australia using a combination of water–atmosphere and sediment–water flux measurements, water column sampling and pore water analysis. The reservoir was clearly a net source as surface waters were supersaturated with CH4 and N2O. CH4 flux rates were one to two orders of magnitude higher than N2O rates when expressed as CO2 equivalents. Atmospheric CH4 fluxes were dominated by ebullition (<60%) relative to diffusive fluxes and ranged from 165 to 6526 mg CO2 eq m−2 d−1. Dissolved CH4 concentrations in sediment pore waters were approximately 5 000 000% supersaturated. However, dissolved N2O concentrations were 140 to 220% supersaturated and generally confined to the water column greatly reducing the likelihood of ebullition. The flux measurements from this study support past findings that demonstrate the potential important contribution of emissions from subtropical reservoirs to overall GHG budgets. Results suggest future efforts to monitor and model emissions that concentrate on quantifying the ebullition pathway for CH4 as this was dominant relative to diffusive fluxes as well as total N2O emissions.

scholarly journals Greenhouse gas emissions from fen soils used for forage production in northern Germany

2016 ◽  
Vol 13 (18) ◽  
pp. 5221-5244 ◽  
Author(s):  
Arne Poyda ◽  
Thorsten Reinsch ◽  
Christof Kluß ◽  
Ralf Loges ◽  
Friedhelm Taube
Keyword(s):  
Ghg Emissions ◽  
Farming Systems ◽  
Forage Yield ◽  
N2o Emissions ◽  
Net Energy ◽  
Forage Production ◽  
Climatic Impact ◽  
Northern Germany ◽  
Ch4 And N2o

Abstract. A large share of peatlands in northwestern Germany is drained for agricultural purposes, thereby emitting high amounts of greenhouse gases (GHGs). In order to quantify the climatic impact of fen soils in dairy farming systems of northern Germany, GHG exchange and forage yield were determined on four experimental sites which differed in terms of management and drainage intensity: (a) rewetted and unutilized grassland (UG), (b) intensive and wet grassland (GW), (c) intensive and moist grassland (GM) and (d) arable forage cropping (AR). Net ecosystem exchange (NEE) of CO2 and fluxes of CH4 and N2O were measured using closed manual chambers. CH4 fluxes were significantly affected by groundwater level (GWL) and soil temperature, whereas N2O fluxes showed a significant relation to the amount of nitrate in top soil. Annual balances of all three gases, as well as the global warming potential (GWP), were significantly correlated to mean annual GWL. A 2-year mean GWP, combined from CO2–C eq. of NEE, CH4 and N2O emissions, as well as C input (slurry) and C output (harvest), was 3.8, 11.7, 17.7 and 17.3 Mg CO2–C eq. ha−1 a−1 for sites UG, GW, GM and AR, respectively (standard error (SE) 2.8, 1.2, 1.8, 2.6). Yield-related emissions for the three agricultural sites were 201, 248 and 269 kg CO2–C eq. (GJ net energy lactation; NEL)−1 for sites GW, GM and AR, respectively (SE 17, 9, 19). The carbon footprint of agricultural commodities grown on fen soils depended on long-term drainage intensity rather than type of management, but management and climate strongly influenced interannual on-site variability. However, arable forage production revealed a high uncertainty of yield and therefore was an unsuitable land use option. Lowest yield-related GHG emissions were achieved by a three-cut system of productive grassland swards in combination with a high GWL (long-term mean  ≤  20 cm below the surface).

The Evaluation of the Levels of Greenhouse Gases due to Activities Carried Out on a Livestock Farm

2017 ◽  
Vol 68 (8) ◽  
pp. 1700-1702
Author(s):  
Valeriu Danciulescu ◽  
Andrei Vasile ◽  
Luoana Florentina Pascu ◽  
Bogdan Stanescu ◽  
Ileana Nicolescu
Keyword(s):  
Agricultural Sector ◽  
Ghg Emissions ◽  
Pollutant Dispersion ◽  
Ambient Air ◽  
N2o Emissions ◽  
Measured Temperature ◽  
Animal Shelters ◽  
Livestock Sector ◽  
Land Cultivation ◽  
Ch4 And N2o

The paper presents the results of tests carried out on a Romanian farm with the purpose of assessing greenhouse gas (GHG) emissions specific to agricultural activities. GHG emissions from the agricultural sector come mainly from the livestock sector, manure management, land cultivation and fertilization. The tests carried out mainly focused on the CO2 , CH4 and N2O emissions generated from related manure storage activities as well as the emission level identified in animal shelters. For a correct interpretation of the results obtained, at the same time with the measurement of the GHG concentration, the weather parameters were measured: temperature, humidity and wind direction. The results obtained revealed the presence of these compounds in the air in the animal shelters and in the ambient air (CO2 and CH4) in concentrations that are in the range identified in similar studies around the world. The pollutant dispersion in the air leads to a reduction in the pollutant concentration with increasing distance from the observed source as well as the measurement points at 50, 100 and 500 m, that reaches values below the detection limit of the instrument for CH4 and N2O, whereas in the case of CO2 it reaches the level of the usual concentration in the ambient air.

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