scholarly journals Impact of water table level on annual carbon and greenhouse gas balances of a restored peat extraction area

2016 ◽  
Vol 13 (9) ◽  
pp. 2637-2651 ◽  
Author(s):  
Järvi Järveoja ◽  
Matthias Peichl ◽  
Martin Maddison ◽  
Kaido Soosaar ◽  
Kai Vellak ◽  
...  

Abstract. Peatland restoration may provide a potential after-use option to mitigate the negative climate impact of abandoned peat extraction areas; currently, however, knowledge about restoration effects on the annual balances of carbon (C) and greenhouse gas (GHG) exchanges is still limited. The aim of this study was to investigate the impact of contrasting mean water table levels (WTLs) on the annual C and GHG balances of restoration treatments with high (ResH) and low (ResL) WTL relative to an unrestored bare peat (BP) site. Measurements of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes were conducted over a full year using the closed chamber method and complemented by measurements of abiotic controls and vegetation cover. Three years following restoration, the difference in the mean WTL resulted in higher bryophyte and lower vascular plant cover in ResH relative to ResL. Consequently, greater gross primary production and autotrophic respiration associated with greater vascular plant cover were observed in ResL compared to ResH. However, the means of the measured net ecosystem CO2 exchanges (NEE) were not significantly different between ResH and ResL. Similarly, no significant differences were observed in the respective means of CH4 and N2O exchanges. In comparison to the two restored sites, greater net CO2, similar CH4 and greater N2O emissions occurred in BP. On the annual scale, ResH, ResL and BP were C sources of 111, 103 and 268 g C m−2 yr−1 and had positive GHG balances of 4.1, 3.8 and 10.2 t CO2 eq ha−1 yr−1, respectively. Thus, the different WTLs had a limited impact on the C and GHG balances in the two restored treatments 3 years following restoration. However, the C and GHG balances in ResH and ResL were considerably lower than in BP due to the large reduction in CO2 emissions. This study therefore suggests that restoration may serve as an effective method to mitigate the negative climate impacts of abandoned peat extraction areas.

2015 ◽  
Vol 12 (20) ◽  
pp. 17177-17218 ◽  
Author(s):  
J. Järveoja ◽  
M. Peichl ◽  
M. Maddison ◽  
K. Soosaar ◽  
K. Vellak ◽  
...  

Abstract. Peatland restoration may provide a potential after-use option to mitigate the negative climate impact of abandoned peat extraction areas; currently, however, knowledge about restoration effects on the annual balances of carbon (C) and greenhouse gas (GHG) exchanges is still limited. The aim of this study was to investigate the impact of contrasting water table levels (WTL) on the annual C and GHG balances of restoration treatments with high (Res-H) and low (Res-L) WTL relative to an unrestored bare peat (BP) site. Measurements of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes were conducted over a full year using the closed chamber method and complemented by measurements of abiotic controls and vegetation cover. Three years following restoration, the difference in the mean WTL resulted in higher bryophyte and lower vascular plant cover in Res-H relative to Res-L. Consequently, greater gross primary production and autotrophic respiration associated with greater vascular plant cover were observed in Res-L compared to Res-H. However, the means of the measured net ecosystem CO2 exchanges (NEE) were not significantly different between Res-H and Res-L. Similarly, no significant differences were observed in the respective means of CH4 and N2O exchanges in Res-H and Res-L, respectively. In comparison to the two restored sites, greater net CO2, similar CH4 and greater N2O emissions occurred in BP. On the annual scale, Res-H, Res-L and BP were C sources of 111, 103 and 268 g C m−2 yr−1 and had positive GHG balances of 4.1, 3.8 and 10.2 t CO2 eq ha−1 yr−1, respectively. Thus, the different WTLs had a limited impact on the C and GHG balances in the two restored treatments three years following restoration. However, the C and GHG balances in Res-H and Res-L were considerably lower than in BP owing to the large reduction in CO2 emissions. This study therefore suggests that restoration may serve as an effective method to mitigate the negative climate impacts of abandoned peat extraction areas.


Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1477
Author(s):  
Antonio Marín-Martínez ◽  
Alberto Sanz-Cobeña ◽  
Mª Angeles Bustamante ◽  
Enrique Agulló ◽  
Concepción Paredes

In semi-arid vineyard agroecosystems, highly vulnerable in the context of climate change, the soil organic matter (OM) content is crucial to the improvement of soil fertility and grape productivity. The impact of OM, from compost and animal manure, on soil properties (e.g., pH, oxidisable organic C, organic N, NH4+-N and NO3−-N), grape yield and direct greenhouse gas (GHG) emission in vineyards was assessed. For this purpose, two wine grape varieties were chosen and managed differently: with a rain-fed non-trellising vineyard of Monastrell, a drip-irrigated trellising vineyard of Monastrell and a drip-irrigated trellising vineyard of Cabernet Sauvignon. The studied fertiliser treatments were without organic amendments (C), sheep/goat manure (SGM) and distillery organic waste compost (DC). The SGM and DC treatments were applied at a rate of 4600 kg ha−1 (fresh weight, FW) and 5000 kg ha−1 FW, respectively. The use of organic amendments improved soil fertility and grape yield, especially in the drip-irrigated trellising vineyards. Increased CO2 emissions were coincident with higher grape yields and manure application (maximum CO2 emissions = 1518 mg C-CO2 m−2 d−1). In contrast, N2O emissions, mainly produced through nitrification, were decreased in the plots showing higher grape production (minimum N2O emissions = −0.090 mg N2O-N m−2 d−1). In all plots, the CH4 fluxes were negative during most of the experiment (−1.073−0.403 mg CH4-C m−2 d−1), indicating that these ecosystems can represent a significant sink for atmospheric CH4. According to our results, the optimal vineyard management, considering soil properties, yield and GHG mitigation together, was the use of compost in a drip-irrigated trellising vineyard with the grape variety Monastrell.


2009 ◽  
Vol 6 (3) ◽  
pp. 4803-4828 ◽  
Author(s):  
M. Lund ◽  
T. R. Christensen ◽  
M. Mastepanov ◽  
A. Lindroth ◽  
L. Ström

Abstract. Peatlands are important ecosystems in the context of biospheric feedback to climate change, due to the large storage of organic C in peatland soils. Nitrogen deposition and increased nutrient availability in soils following climate warming may cause changes in these ecosystems affecting greenhouse gas exchange. We have conducted an N and P fertilization experiment in two Swedish bogs subjected to high and low background N deposition, and measured the exchange of CO2, CH4 and N2O using the closed chamber technique. During the second year of fertilization, both gross primary production and ecosystem respiration were significantly increased by N addition in the northernmost site where background N deposition is low, while gross primary production was stimulated by P addition in the southern high N deposition site. In addition, a short-term response in respiration was seen following fertilization, probably associated with rapid growth of nutrient-limited soil microorganisms. No treatment effect was seen on the CH4 exchange, while N2O emissions peaks were detected in N fertilized plots indicating the importance of taking N2O into consideration under increased N availability. In a longer term, increased nutrient availability will cause changes in plant competitive patterns. The related effect on the future net greenhouse gas exchange is likely dependent on the mixture of nutrients being made available and which plant functional types that benefit from it, in combination with other changes related to global warming.


Botany ◽  
2018 ◽  
Vol 96 (11) ◽  
pp. 779-791 ◽  
Author(s):  
Félix Gagnon ◽  
Line Rochefort ◽  
Claude Lavoie

There are very few studies on the spontaneous revegetation of cutover fens or bogs from which peat has been extracted to the minerotrophic layers. Most peatlands with fen-type residual peat have problems regenerating a plant cover satisfactorily from a restoration point of view. We nevertheless found a site (Moss Spur, Manitoba, Canada) presenting a substantial and diversified spontaneous plant cover. We estimated that the site would provide insights about natural revegetation processes operating in peatlands. Vegetation assemblages and environmental conditions were surveyed 19 years after extraction activities ceased. Moss Spur has densely revegetated (163 plant species, vegetation cover of 94%) with minimal human assistance. However, the composition of plant assemblages varies considerably across the site, depending on certain abiotic variables, particularly water pH, water table level, and the thickness of the residual peat layer. Moss Spur was remarkably wet considering the past peat extraction activities and the absence of active rewetting procedures. The high water table level may in part explain the successful revegetation. However, plant assemblages were not of equal quality from a restoration perspective. Some assemblages were highly diversified, and especially those dominated by Scirpus cyperinus, a species that should be further considered in peatland restoration projects to direct the recovery of the peatland towards a natural fen species composition.


2015 ◽  
Vol 12 (18) ◽  
pp. 15301-15336 ◽  
Author(s):  
D. E. Pelster ◽  
M. C. Rufino ◽  
T. Rosenstock ◽  
J. Mango ◽  
G. Saiz ◽  
...  

Abstract. Few field studies examine greenhouse gas (GHG) emissions from African agricultural systems resulting in high uncertainty for national inventories. We provide here the most comprehensive study in Africa to date, examining annual CO2, CH4 and N2O emissions from 59 plots, across different vegetation types, field types and land classes in western Kenya. The study area consists of a lowland area (approximately 1200 m a.s.l.) rising approximately 600 m to a highland plateau. Cumulative annual fluxes ranged from 2.8 to 15.0 Mg CO2-C ha−1, −6.0 to 2.4 kg CH4-C ha−1 and −0.1 to 1.8 kg N2O-N ha−1. Management intensity of the plots did not result in differences in annual fluxes for the GHGs measured (P = 0.46, 0.67 and 0.14 for CO2, N2O and CH4 respectively). The similar emissions were likely related to low fertilizer input rates (≤ 20 kg ha−1). Grazing plots had the highest CO2 fluxes (P = 0.005); treed plots were a larger CH4 sink than grazing plots (P = 0.05); while N2O emissions were similar across vegetation types (P = 0.59). This case study is likely representative for low fertilizer input, smallholder systems across sub-Saharan Africa, providing critical data for estimating regional or continental GHG inventories. Low crop yields, likely due to low inputs, resulted in high (up to 67 g N2O-N kg−1 aboveground N uptake) yield-scaled emissions. Improving crop production through intensification of agricultural production (i.e. water and nutrient management) may be an important tool to mitigate the impact of African agriculture on climate change.


Soil Systems ◽  
2019 ◽  
Vol 3 (1) ◽  
pp. 8 ◽  
Author(s):  
Rivka Fidel ◽  
David Laird ◽  
Timothy Parkin

Biochar application to soil has been proposed as a means for reducing soil greenhouse gas emissions and mitigating climate change. The effects, however, of interactions between biochar, moisture and temperature on soil CO2 and N2O emissions, remain poorly understood. Furthermore, the applicability of lab-scale observations to field conditions in diverse agroecosystems remains uncertain. Here we investigate the impact of a mixed wood gasification biochar on CO2 and N2O emissions from loess-derived soils using: (1) controlled laboratory incubations at three moisture (27, 31 and 35%) and three temperature (10, 20 and 30 °C) levels and (2) a field study with four cropping systems (continuous corn, switchgrass, low diversity grass mix and high diversity grass-forb mix). Biochar reduced N2O emissions under specific temperatures and moistures in the laboratory and in the continuous corn cropping system in the field. However, the effect of biochar on N2O emissions was only significant in the field and no effect on cumulative CO2 emissions was observed. Cropping system also had a significant effect in the field study, with soils in grass and grass-forb cropping systems emitting more CO2 and less N2O than corn cropping systems. Observed biochar effects were consistent with previous studies showing that biochar amendments can reduce soil N2O emissions under specific but not all, conditions. The disparity in N2O emission responses at the lab and field scales suggests that laboratory incubation experiments may not reliably predict the impact of biochar at the field scale.


2016 ◽  
Vol 56 (3) ◽  
pp. 153 ◽  
Author(s):  
G. Legesse ◽  
K. A. Beauchemin ◽  
K. H. Ominski ◽  
E. J. McGeough ◽  
R. Kroebel ◽  
...  

The present study compared the greenhouse gas (GHG) emissions, and breeding herd and land requirements of Canadian beef production in 1981 and 2011. In the analysis, temporal and regional differences in feed types, feeding systems, cattle categories, average daily gains and carcass weights were considered. Emissions were estimated using life-cycle assessment (cradle to farm gate), based primarily on Holos, a Canadian whole-farm emissions model. In 2011, beef production in Canada required only 71% of the breeding herd (i.e. cows, bulls, calves and replacement heifers) and 76% of the land needed to produce the same amount of liveweight for slaughter as in 1981. Compared with 1981, in 2011 the same amount of slaughter weight was produced, with a 14% decline in CH4 emissions, 15% decline in N2O emissions and a 12% decline in CO2 emissions from fossil fuel use. Enteric CH4 production accounted for 73% of total GHG emissions in both years. The estimated intensity of GHG emissions per kilogram of liveweight that left the farm was 14.0 kg CO2 equivalents for 1981 and 12.0 kg CO2 equivalents for 2011, a decline of 14%. A significant reduction in GHG intensity over the past three decades occurred as a result of increased average daily gain and slaughter weight, improved reproductive efficiency, reduced time to slaughter, increased crop yields and a shift towards high-grain diets that enabled cattle to be marketed at an earlier age. Future studies are necessary to examine the impact of beef production on other sustainability metrics, including water use, air quality, biodiversity and provision of ecosystems services.


2018 ◽  
Author(s):  
Mika Korkiakoski ◽  
Juha-Pekka Tuovinen ◽  
Timo Penttilä ◽  
Sakari Sarkkola ◽  
Paavo Ojanen ◽  
...  

Abstract. The most common forest management method in Fennoscandia is rotation forestry including clearcutting and forest regeneration. In clearcutting, stem wood is removed and the logging residues are either removed or left on site. Clearcutting changes the microclimate and vegetation structure at the site, both of which impact the site's carbon balance. Peat soils with poor aeration and high carbon (C) densities are especially prone to such changes, and significant changes in C stocks and greenhouse gas exchange can be expected. We measured carbon dioxide (CO2) and energy fluxes with the eddy covariance method for two years (April 2016–March 2018) on a peatland drained for forestry. After the clearcutting, we observed a significant rise (23 cm) in the water table level. The site was also a large CO2 source (first year: 3086 ± 120 g CO2 m−2yr−1, second year: 2072 ± 141 g CO2 m−2 yr−1) after the clearcutting. These large CO2 emissions resulted from the collapse of gross primary production (GPP) following the removal of photosynthesizing trees and the decline of ground vegetation. During the second summer (June–August) after the clearcutting, GPP had already increased by 96 % and total ecosystem respiration decreased by 14 % from the previous summer. As a result, net CO2 emissions decreased during the second summer after clearcutting compared to the first one. The Bowen ratios were different in 2016 and 2017, starting at 2.6 in May 2016 and decreasing to less than 1.0 in August 2016, while in 2017 it varied mostly within 0.6–1.0. This was due to a 33 % decrease in the sensible heat flux and a 40 % increase in the latent heat flux from the 2016 values, probably due to the recovery of ground vegetation that increased evapotranspiration and albedo of the site. In addition to CO2 and energy fluxes, we measured methane (CH4) and nitrous oxide (N2O) fluxes with manual chambers. After the clearcutting, the site turned from a small CH4 sink into a small source and from N2O-neutral to a significant N2O source. Compared to the large CO2 emissions, the global warming potential (GWP100) of the CH4 emissions was negligible. Also, the GWP100 due to increased N2O emissions was less than 10 % of that of the CO2 emission change.


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