scholarly journals Soil N2O, CH4, and CO2 Fluxes in Forest, Grassland, and Tillage/No-Tillage Croplands in French Guiana (Amazonia)

Soil Systems ◽  
2019 ◽  
Vol 3 (2) ◽  
pp. 29
Author(s):  
Caroline Petitjean ◽  
Cécile Le Gall ◽  
Célia Pontet ◽  
Kenji Fujisaki ◽  
Bernard Garric ◽  
...  
Keyword(s):  
French Guiana ◽  
Agricultural Landscape ◽  
Ghg Emissions ◽  
Co2 Exchange ◽  
No Tillage ◽  
Co2 Fluxes ◽  
Agricultural Systems ◽  
Brachiaria Ruziziensis ◽  
Agricultural Use ◽  
One Year

The agricultural landscape of French Guiana (Amazonia) is expected to undergo substantial change as a result of rapid population growth in the region. Such changes in the landscape will lead to the conversion of tropical forests into land destined for agricultural use. Little information is available on the effect of different agricultural systems on greenhouse gas (GHG) emissions in French Guiana. For our experiment, two hectares of forest were cleared, without the use of fire, at the Combi experimental site (sandy-clayey Ferralsol) at the end of 2008. After one year with legume and grass cover, the site was modified to include the following three fertilized agricultural systems: (1) Grassland (Brachiaria ruziziensis, mowed), (2) cropland (maize/soybean rotation) with disc tillage, and (3) cropland (maize/soybean rotation) with no-tillage in direct seeding. Soil N2O, CH4, and CO2 fluxes were measured with dark chambers from May 2011 to November 2014. Our results show that grassland was a significantly lower emitter of N2O but a significantly higher emitter of CH4 compared to the two cropland systems studied. We did not observe significant differences between the two cropland systems for N2O and CH4 fluxes. Measurements of the net ecosystem CO2 exchange would be useful to better compare the role of different agricultural systems as a source of GHGs.

scholarly journals Determination of the carbon budget of a pasture: effect of system boundaries and flux uncertainties

2015 ◽  
Vol 12 (23) ◽  
pp. 20071-20100 ◽  
Author(s):  
R. Felber ◽  
D. Bretscher ◽  
A. Münger ◽  
A. Neftel ◽  
C. Ammann
Keyword(s):  
Carbon Budget ◽  
Agricultural Sector ◽  
Ghg Emissions ◽  
C Sequestration ◽  
Co2 Exchange ◽  
System Boundaries ◽  
Simultaneous Application ◽  
Soil C ◽  
Ecosystem Carbon ◽  
One Year

Abstract. Carbon (C) sequestration in the soil is considered as a potential important mechanism to mitigate greenhouse gas (GHG) emissions of the agricultural sector. It can be quantified by the net ecosystem carbon budget (NECB) describing the change of soil C as the sum of all relevant import and export fluxes. NECB was investigated here in detail for an intensively grazed dairy pasture in Switzerland. Two budget approaches with different system boundaries were applied: NECBtot for system boundaries including the grazing cows and NECBpast for system boundaries excluding the cows. CO2 and CH4 exchange induced by soil/vegetation processes as well as direct emissions by the animals were derived from eddy covariance measurements. Other C fluxes were either measured (milk yield, concentrate feeding) or derived based on animal performance data (intake, excreta). For the investigated year, both approaches resulted in a small non-significant C loss: NECBtot - 13 ± 61 g C m−2 yr−1 and NECBpast - 17 ± 81 g C m−2 yr−1. The considerable uncertainties, depending on the approach, were mainly due to errors in the CO2 exchange or in the animal related fluxes. The associated GHG budget revealed CH4 emissions from the cows to be the major contributor, but with much lower uncertainty compared to NECB. Although only one year of data limit the representativeness of the carbon budget results, they demonstrated the important contribution of the non-CO2 fluxes depending on the chosen system boundaries and the effect of their propagated uncertainty in an exemplary way. The simultaneous application and comparison of both NECB approaches provides a useful consistency check for the carbon budget determination and can help to identify and eliminate systematic errors.

scholarly journals GIS analysis of change in an agriculture landscape in Central Finland

1996 ◽  
Vol 5 (6) ◽  
pp. 567-576 ◽  
Author(s):  
Riitta Ruuska ◽  
Juha Helenius
Keyword(s):  
Agricultural Landscape ◽  
Average Rate ◽  
Aerial Photographs ◽  
Landscape Elements ◽  
Average Proportion ◽  
Linear Landscape Elements ◽  
Land Survey ◽  
Ecosystem Level ◽  
Agricultural Use ◽  
Index Value

Changes in landscape over a period of 50 years were analysed in a rural area of 324 ha in Central Finland. The data were digitized from aerial photographs of the National Land Survey taken in 1944, 1959, 1979 and 1991, and analysed with the IDRISI™ geographic information system (GIS). The average proportion of land in agricultural use in the sample area was 17.4%. The arable area declined from the maximum of 62.3 ha (1959) to 47.6 ha. The total length of linear landscape elements, predominantly ditch bank habitats, halved, from 876 m/ha of field (1944) to 449 m/ha by the end of the period. The average rate of loss of field boundary habitat was 9.1 m/ha/ year. At the same time, the Shannon-Weaver index of diversity of agricultural landscape elements dropped from 0.37 to 0.24. The number of field parcels declined by 29%, and the mean parcel size increased by 45%, from 1.2 ha to 1.7 ha. The index value of the fractal dimension measuring the complexity of parcel shapes also fell, from 1.88 (1959) to 1.86 (1991). The change in spatial structure reflects the intensification of farming in Finland. Biodiversity at ecosystem level has clearly declined. However, the implications for the agroecosystem and its sustainability are still unknown.

Climate change mitigation for agriculture: water quality benefits and costs

2008 ◽  
Vol 58 (11) ◽  
pp. 2093-2099 ◽  
Author(s):  
Robert Wilcock ◽  
Sandy Elliott ◽  
Neale Hudson ◽  
Stephanie Parkyn ◽  
John Quinn
Keyword(s):  
New Zealand ◽  
Greenhouse Gas ◽  
Habitat Quality ◽  
Waste Treatment ◽  
Ghg Emissions ◽  
Water Soluble ◽  
Soil Conditions ◽  
Nitrification Inhibitors ◽  
Agricultural Systems ◽  
Management Options

New Zealand is unique in that half of its national greenhouse gas (GHG) inventory derives from agriculture - predominantly as methane (CH4) and nitrous oxide (N2O), in a 2:1 ratio. The remaining GHG emissions predominantly comprise carbon dioxide (CO2) deriving from energy and industry sources. Proposed strategies to mitigate emissions of CH4 and N2O from pastoral agriculture in New Zealand are: (1) utilising extensive and riparian afforestation of pasture to achieve CO2 uptake (carbon sequestration); (2) management of nitrogen through budgeting and/or the use of nitrification inhibitors, and minimizing soil anoxia to reduce N2O emissions; and (3) utilisation of alternative waste treatment technologies to minimise emissions of CH4. These mitigation measures have associated co-benefits and co-costs (disadvantages) for rivers, streams and lakes because they affect land use, runoff loads, and receiving water and habitat quality. Extensive afforestation results in lower specific yields (exports) of nitrogen (N), phosphorus (P), suspended sediment (SS) and faecal matter and also has benefits for stream habitat quality by improving stream temperature, dissolved oxygen and pH regimes through greater shading, and the supply of woody debris and terrestrial food resources. Riparian afforestation does not achieve the same reductions in exports as extensive afforestation but can achieve reductions in concentrations of N, P, SS and faecal organisms. Extensive afforestation of pasture leads to reduced water yields and stream flows. Both afforestation measures produce intermittent disturbances to waterways during forestry operations (logging and thinning), resulting in sediment release from channel re-stabilisation and localised flooding, including formation of debris dams at culverts. Soil and fertiliser management benefits aquatic ecosystems by reducing N exports but the use of nitrification inhibitors, viz. dicyandiamide (DCD), to achieve this may under some circumstances impair wetland function to intercept and remove nitrate from drainage water, or even add to the overall N loading to waterways. DCD is water soluble and degrades rapidly in warm soil conditions. The recommended application rate of 10 kg DCD/ha corresponds to 6 kg N/ha and may be exceeded in warm climates. Of the N2O produced by agricultural systems, approximately 30% is emitted from indirect sources, which are waterways draining agriculture. It is important therefore to focus strategies for managing N inputs to agricultural systems generally to reduce inputs to wetlands and streams where these might be reduced to N2O. Waste management options include utilizing the CH4 resource produced in farm waste treatment ponds as a source of energy, with conversion to CO2 via combustion achieving a 21-fold reduction in GHG emissions. Both of these have co-benefits for waterways as a result of reduced loadings. A conceptual model derived showing the linkages between key land management practices for greenhouse gas mitigation and key waterway values and ecosystem attributes is derived to aid resource managers making decisions affecting waterways and atmospheric GHG emissions.

scholarly journals O<sub>2</sub> : CO<sub>2</sub> exchange ratio for net turbulent flux observed in an urban area of Tokyo, Japan, and its application to an evaluation of anthropogenic CO<sub>2</sub> emissions

2020 ◽  
Vol 20 (9) ◽  
pp. 5293-5308
Author(s):  
Shigeyuki Ishidoya ◽  
Hirofumi Sugawara ◽  
Yukio Terao ◽  
Naoki Kaneyasu ◽  
Nobuyuki Aoki ◽  
...  
Keyword(s):  
Fuel Consumption ◽  
Urban Area ◽  
Co2 Emission ◽  
Co2 Flux ◽  
Co2 Exchange ◽  
Co2 Fluxes ◽  
Diurnal Cycles ◽  
Co2 Concentrations ◽  
Human Respiration ◽  
Two Peaks

Abstract. In order to examine O2 consumption and CO2 emission in a megacity, continuous observations of atmospheric O2 and CO2 concentrations, along with CO2 flux, have been carried out simultaneously since March 2016 at the Yoyogi (YYG) site located in the middle of Tokyo, Japan. An average O2 : CO2 exchange ratio for net turbulent O2 and CO2 fluxes (ORF) between the urban area and the overlaying atmosphere was obtained based on an aerodynamic method using the observed O2 and CO2 concentrations. The yearly mean ORF was found to be 1.62, falling within the range of the average OR values of liquid and gas fuels, and the annual average daily mean O2 flux at YYG was estimated to be −16.3 µmol m−2 s−1 based on the ORF and CO2 flux. By using the observed ORF and CO2 flux, along with the inventory-based CO2 emission from human respiration, we estimated the average diurnal cycles of CO2 fluxes from gas and liquid fuel consumption separately for each season. Both the estimated and inventory-based CO2 fluxes from gas fuel consumption showed average diurnal cycles with two peaks, one in the morning and another one in the evening; however, the evening peak of the inventory-based gas consumption was much larger than that estimated from the CO2 flux. This can explain the discrepancy between the observed and inventory-based total CO2 fluxes at YYG. Therefore, simultaneous observations of ORF and CO2 flux are useful in validating CO2 emission inventories from statistical data.

scholarly journals Carbon Footprint and Life-Cycle Costs of Maize Production in Conventional and Non-Inversion Tillage Systems

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1877
Author(s):  
Małgorzata Holka ◽  
Jerzy Bieńkowski
Keyword(s):  
Life Cycle ◽  
Carbon Footprint ◽  
Cover Crops ◽  
Ghg Emissions ◽  
Nitrogen Fertilizers ◽  
Life Cycle Costs ◽  
Agricultural Practice ◽  
No Tillage ◽  
Tillage Systems ◽  
Maize Production

Given the problem of climate change and the requirements laid down by the European Union in the field of gradual decarbonization of production, it is necessary to implement solutions of reducing greenhouse gas (GHG) emissions into agricultural practice. This research paper aimed to evaluate the carbon footprint and life-cycle costs of grain maize production in various tillage systems. The material for the analyses was data from 2015–2017 collected on 15 farms located in the Wielkopolska region (Poland) and growing maize for grain in three tillage systems: conventional, reduced, and no-tillage. The life-cycle assessment and life-cycle costing methodologies were applied to assess the GHG emissions and costs associated with the grain maize production in the stages from “cradle-to-farm gate”, i.e., from obtaining raw materials and producing means for agricultural production, through the processes of maize cultivation to grain harvesting. The calculated values of the carbon footprint indicator for maize production in conventional, reduced, and no-tillage systems were 2347.4, 2353.4, and 1868.7 CO2 eq. ha−1, respectively. The largest source of GHG emissions was the use of nitrogen fertilizers. Non-inversion tillage with cover crops and leaving a large amount of crop residues in the field increased the sequestration of organic carbon and contributed to a significant reduction of the carbon footprint in maize production. The conventional tillage system demonstrated the highest overall life-cycle costs per hectare.

scholarly journals Determination of the carbon budget of a pasture: effect of system boundaries and flux uncertainties

2016 ◽  
Vol 13 (10) ◽  
pp. 2959-2969 ◽  
Author(s):  
Raphael Felber ◽  
Daniel Bretscher ◽  
Andreas Münger ◽  
Albrecht Neftel ◽  
Christof Ammann
Keyword(s):  
Carbon Budget ◽  
Agricultural Sector ◽  
Ghg Emissions ◽  
C Sequestration ◽  
Co2 Exchange ◽  
System Boundaries ◽  
Simultaneous Application ◽  
Soil C ◽  
Ecosystem Carbon ◽  
Eddy Covariance Measurements

Abstract. Carbon (C) sequestration in the soil is considered as a potential important mechanism to mitigate greenhouse gas (GHG) emissions of the agricultural sector. It can be quantified by the net ecosystem carbon budget (NECB) describing the change of soil C as the sum of all relevant import and export fluxes. NECB was investigated here in detail for an intensively grazed dairy pasture in Switzerland. Two budget approaches with different system boundaries were applied: NECBtot for system boundaries including the grazing cows and NECBpast for system boundaries excluding the cows. CO2 and CH4 exchange induced by soil/vegetation processes as well as direct emissions by the animals were derived from eddy covariance measurements. Other C fluxes were either measured (milk yield, concentrate feeding) or derived based on animal performance data (intake, excreta). For the investigated year, both approaches resulted in a small near-neutral C budget: NECBtot −27 ± 62 and NECBpast 23 ± 76 g C m−2 yr−1. The considerable uncertainties, depending on the approach, were mainly due to errors in the CO2 exchange or in the animal-related fluxes. The comparison of the NECB results with the annual exchange of other GHG revealed CH4 emissions from the cows to be the major contributor in terms of CO2 equivalents, but with much lower uncertainty compared to NECB. Although only 1 year of data limit the representativeness of the carbon budget results, they demonstrate the important contribution of the non-CO2 fluxes depending on the chosen system boundaries and the effect of their propagated uncertainty in an exemplary way. The simultaneous application and comparison of both NECB approaches provides a useful consistency check for the carbon budget determination and can help to identify and eliminate systematic errors.

Influence of Light Intensity on Methanotrophic Bacterial Activity in Petit Saut Reservoir, French Guiana

1999 ◽  
Vol 65 (2) ◽  
pp. 534-539 ◽  
Author(s):  
J. F. Dumestre ◽  
J. Guézennec ◽  
C. Galy-Lacaux ◽  
R. Delmas ◽  
S. Richard ◽  
...  
Keyword(s):  
Methane Emission ◽  
French Guiana ◽  
Methanotrophic Bacteria ◽  
Phospholipid Analysis ◽  
In Situ Conditions ◽  
The Mean ◽  
One Year ◽  
Petit Saut ◽  
Potential Inhibitors

ABSTRACT One year after impoundment in January 1994, methanotrophic bacteria in Petit Saut Reservoir (French Guiana) were active at the oxic-anoxic interface. This activity was revealed by the sudden extinction of diffusive methane emission (600 metric tons of CH4 · day−1 for the whole lake surface area, i.e., 360 km2). Lifting of inhibition was suspected. After reviewing the potential inhibitors of this physiological guild (O2, NH4 +, sulfides) and considering the similarities with nitrifiers, we suggest that sunlight influenced the methanotrophic bacteria. On the basis of phospholipid analysis, only a type II methanotrophic community was identified in the lake. Both growth and methanotrophic activity of an enriched culture, obtained in the laboratory, were largely inhibited by illumination over 150 microeinsteins · m−2 · s−1. These results were confirmed on a pure culture of Methylosinus trichosporium OB3B. In situ conditions showed that water transparency was quite stable in 1994 and 1995 and that the oxycline moved steadily deeper until January 1995. Considering the mean illumination profile during this period, we showed that removal of methanotrophic growth inhibition could only occur below a 2-m depth. The oxycline reached this level in October 1994, allowing methanotrophic bacteria to develop and to consume the entire methane emission 4 months later.

Production of summer crops in northern New South Wales. II. Effects of tillage and crop rotation on yields of sorghum

1992 ◽  
Vol 43 (1) ◽  
pp. 123 ◽  
Author(s):  
JF Holland ◽  
DF Herridge
Keyword(s):  
New South ◽  
New South Wales ◽  
Threshold Value ◽  
No Tillage ◽  
Tillage Practices ◽  
South Wales ◽  
Carry Over ◽  
One Year ◽  
N Fertility ◽  
Rotation Crop

Two crops of sorghum were grown in successive summer seasons at 3 sites on alkaline, black earth soils near Tamworth, New South Wales following either soyabeans, mungbeans, cowpeas, pigeonpeas, sunflowers or sorghum. Tillage practices were cultivation using a chisel plough and scarifier, and no-tillage using atrazine and glyphosate for weed control. Variation in grain yield (1.0-8.4 t/ha) was largely associated with variation in Dec.-Feb. rainfall (128-475 mm). An average of 15 kg grain/ha was produced for each mm water above the threshold value of 83 mm. At the high (Site A) and low (Site C) N-fertility sites, the rotation effect on sorghum yields was significant for one year, but did not carry over to a second sorghum crop. Cowpeas were the best rotation crop, followed by sunflowers mungbeans and soyabeans. At the low N-fertility site, sorghum following cowpeas outyielded sorghum after sorghum by 47% in the unfertilized plots and by an aExperiments to examine the effects of tillage practice and crop sequence on the production of sorghum grain in northern New South Wales are described. Two crops of sorghum were grown in successive seasons at three sites on alkaline, black earth soils near Tamworth following either soybean, mungbean, cowpea, pigeonpea, sunflower or sorghum. Tillage practices were cultivation using a chisel plough and scarifier, and no-tillage using atrazine and glyphosate for weed control. Variation in grain yield (1.0 to 8.4 t/ha) was largely associated with variation in December-February rainfall (128 to 475 mm). We calculated that an average of 15 kg/ha of grain was produced for each mm water above the threshold value of 83 rnm. At the high (Site A) and low (Site C) N-fertility sites, the rotation effect on sorghum yields was significant for one year, but did not carry over to a second sorghum crop. Cowpea was the best rotation crop, followed by sunflower, mungbean and soybean. At the low N-fertility site, sorghum following cowpea outyielded sorghum after sorghum by 47% in the unfertilized plots and by an average of 27% over all N treatments. It is likely that the increased yields of sorghum in the rotation plots resulted from higher levels of plant available N from both N2 fixation activity (legumes only) and reduced amounts of N removed with the harvested grain (particularly cowpea and sunflower). At the non-responsive, moderate-fertility Site B, water, rather than N, was limiting. Responses to no-tillage were apparent only in the very dry 1984/85 season (December to February rainfall, 42% below average). In the other three seasons, the cultivated crops outyielded the no-tilled crops or the differences between the two practices were not significant.

scholarly journals Spring protection and watercourse and its relationship with environmental quality in family property, in the Caparaó region of Espírito Santo, Brazil

2021 ◽  
Vol 16 (2) ◽  
pp. 174-181
Author(s):  
Sara Carvalho Failla ◽  
Davi Salgado de Senna ◽  
Fábio Luiz de Oliveira ◽  
Leonard Campos Avellar Machado ◽  
Hélia de Barros Kobi ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Native Species ◽  
Hydrological Cycle ◽  
Floristic Composition ◽  
Soil Conditions ◽  
Inappropriate Use ◽  
Forest Coverage ◽  
Agricultural Use ◽  
One Year ◽  
High Degree

Inappropriate use and management of land has generated processes of environmental degradation, in which the increasing removal of forest coverage has impaired the hydrological cycle, water and soil quality. The objective of this work is to know the effects of the protection of the spring, and the initial part of its watercourse, on the environmental conditions in a family property. The study was carried out on the property located in the Rainha da Paz Community, in Alegre-ES, using indicators used for environmental monitoring, at the beginning in September 2013 and after one year (September 2014) of the Water Planters Project. The quality indicators used in the evaluation clearly show that the initial situation in the spring APP, and APP around the main watercourse was inadequate, in several indicators mainly due to the occupation of the area with agricultural use, specifically pasture, occurring cattle trampling within a radius of 50 meters of the spring's permanent preservation area, causing soil compaction and silting, showing a high degree of degradation, reflecting the lack of environmental adequacy, thus not complying with current environmental legislation. The project promoted improvements in the environmental conditions of the family property, through the natural regeneration of native species, bringing gains to the floristic composition, in addition to improvements in the soil conditions.

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