In presenting this dissertation in partial fulfillment of the requirements for a Postgraduate deg... more In presenting this dissertation in partial fulfillment of the requirements for a Postgraduate degree from the University of Saskatchewan, I agree that the Libraries of this University may make it freely available for inspection. I further agree that permission for copying of this dissertation in any manner, in whole or in part, for scholarly purposes may be granted by the professor or professors who supervised my dissertation work or, in their absence, by the Head of the Department or the Dean of the College in which my dissertation work was done. It is understood that any copying or publication or use of this dissertation or parts thereof for financial gain shall not be allowed without my written permission. It is also understood that due recognition shall be given to me and to the University of Saskatchewan in any scholarly use which may be made of any material in my dissertation. Requests for permission to copy or to make other uses of materials in this dissertation in whole or part should be addressed to:
Centre for Northern Agroforestry and Afforestation Environmental benefits of shelterbelts on agri... more Centre for Northern Agroforestry and Afforestation Environmental benefits of shelterbelts on agricultural farmlands ❑ Shelterbelts accumulate atmospheric C in plant biomass ❑ Increase soil carbon ❑ Reduce N2O emissions due to deep roots ❑ Increase soil CH4 oxidation Knowledge gap-Changes on total farm GHG emissions due to the integration of shelterbelts is not well understood Farm location Farm Elements-Shelterbelt area, Ecotone area and Unsheltered zone
Soil moisture is known to be a major control of greenhouse gas (GHG) emissions from agricultural ... more Soil moisture is known to be a major control of greenhouse gas (GHG) emissions from agricultural soils. However, there is little data regarding GHG exchange from the organic matter-rich soils characteristic of shelterbelts-especially under elevated soil moisture conditions. In the present study, we quantified CO 2 , CH 4 and N 2 O fluxes from shelterbelts under elevated soil moisture (irrigated) and semi-arid (rainfed) conditions. Studies were carried out at the Canada-Saskatchewan Irrigation Diversification Centre (CSIDC) near Outlook, Saskatchewan. Non-steady state vented chambers were used to monitor soil GHG fluxes from three shelterbelts in 2013 and 2014. The shelterbelts consisted of a single row of caragana with a north-south orientation and a single row of Scots pine with either a north-south or east-west orientation. Each shelterbelt was divided into two areas based on whether or not it received irrigation. During the 2-year study period, N 2 O emissions from the irrigated shelterbelts (IR-SB) (0.93 kg N 2 ON ha-1) were significantly greater than those from the rainfed shelterbelts (RF-SB) (0.49 kg N 2 ON ha-1). Soil CH 4 oxidation was significantly lower in the IR-SB compared to the RF-SB (-0.85 and-1.20 kg CH 4-C ha-1 , respectively). Irrigation activities stimulated CO 2 production/emission in 2014, but had no effect on CO 2 emissions during the much drier 2013 season. Correlation analyses indicate a strong dependence of CO 2 and CH 4 fluxes on soil moisture in both IR-SB and RF-SB sites. There was a significant relationship between N 2 O emissions and soil moisture for the IR-SB sites in 2013; however, no such relationship was observed in either the IR-SB or RF-SB sites in 2014. Our study suggests that changes in precipitation patterns and soil moisture regime due to climate change could affect soil-atmosphere exchange of GHGs in shelterbelts; however, elevated soil moisture effect on GHG emissions will depend on the availability of N and C in the shelterbelts.
Agriculture, Ecosystems & Environment, May 1, 2016
Abstract Farm shelterbelts are used as a management tool to reduce erosion, conserve moisture, pr... more Abstract Farm shelterbelts are used as a management tool to reduce erosion, conserve moisture, protect crops and buildings, and sequester carbon. Although carbon storage in shelterbelts has been well researched, there have been no measurements of soil trace gas exchange in shelterbelts relative to cropped fields. Our objective was to quantify, for the first time, soil CO 2 , CH 4 and N 2 O fluxes from shelterbelts and compare them to emissions from adjacent cropped fields to assess their potential for greenhouse gas (GHG) mitigation. During 2013 and 2014, non-steady state vented chambers were used to monitor soil GHG fluxes from nine shelterbelts and their associated cropped fields at three locations within the Boreal plains and Prairies Eco-zones of Saskatchewan Canada. Mean cumulative CO 2 emissions from shelterbelt soils were significantly ( P 2 -C ha −1 yr −1 , respectively). However, soil organic carbon (SOC) storage (0–30 cm) was 27% greater – representing an increase of 28 Mg ha −1 – in the shelterbelts than in the cropped fields. Soil CH 4 oxidation was greater ( P 4 -C ha −1 yr −1 , respectively) and cropped soils emitted significantly ( P 2 O than the shelterbelts (i.e., 2.5 and 0.65 kg N 2 O-N ha −1 yr −1 , respectively). Total seasonal exchange of non-CO 2 GHGs was reduced by 0.55 Mg CO 2 e ha −1 yr −1 in shelterbelts as compared with cropped fields, 98% of which was soil-derived N 2 O. Patterns of soil temperature, moisture and organic matter distribution beneath shelterbelts suggest a modification in soil micro-environment due to shelterbelt establishment and root activity that, in turn, may be responsible for the observed increase in soil CO 2 emissions and CH 4 oxidation. Our data demonstrate that shelterbelts have substantial potential to mitigate GHGs by enhancing C storage and reducing N 2 O emissions, while maintaining a strong CH 4 sink.
The influence of shelterbelts on soil properties and crop yield at various distances from the she... more The influence of shelterbelts on soil properties and crop yield at various distances from the shelterbelt have been studied; however, there are no available data detailing the spatial effects from shelterbelts into adjacent cropped fields on soil-derived greenhouse gas (GHG) emissions. The objective of this study was to quantify, for the first time, changes in soil CO 2 , CH 4 and N 2 O fluxes along replicate (n = 5) transects extending from the center of the shelterbelt to the center of the adjacent agricultural field. The shelterbelt was a 31-year-old, two-row hybrid poplar-caragana shelterbelt located in the parkland region of Saskatchewan Canada. Soil-derived GHG fluxes were measured using non-steady-state vented chambers placed along parallel transects situated within the shelterbelt strip (0H), at the shelterbelt edge (0.2H), at the edge of the adjacent cropped field (0.5H), and in the cropped field at distances of 40 m (1.5H) and 125 m (5H) from the shelterbelt. Summed over the entire study period, cumulative CO 2 emissions were greatest at 0H (8032 AE 502 kg CO 2-C ha À1) and lowest at 5H (3348 AE 329 kg CO 2-C ha À1); however, the decrease in CO 2 emissions at increasing distances away from the shelterbelt was irregular, with soil temperature and organic carbon distribution being the dominant controls. Soil CH 4 oxidation was greatest at 0H (À1447 AE 216 g CH 4-C ha À1), but decreased as distance from the shelterbelt increased. Conversely, soil N 2 O emissions were lowest at 0H (345 AE 15 g N 2 ON ha À1) but increased with increasing distance from the shelterbelt. Patterns of soil CH 4 uptake and N 2 O emissions were strongly correlated with root biomass, and soil temperature and moisture in the upper 30 cm of the soil profile. Tree root distribution may be a key factor in determining the spatial range of shelterbelt effect on GHG emissions in adjacent fields
In presenting this dissertation in partial fulfillment of the requirements for a Postgraduate deg... more In presenting this dissertation in partial fulfillment of the requirements for a Postgraduate degree from the University of Saskatchewan, I agree that the Libraries of this University may make it freely available for inspection. I further agree that permission for copying of this dissertation in any manner, in whole or in part, for scholarly purposes may be granted by the professor or professors who supervised my dissertation work or, in their absence, by the Head of the Department or the Dean of the College in which my dissertation work was done. It is understood that any copying or publication or use of this dissertation or parts thereof for financial gain shall not be allowed without my written permission. It is also understood that due recognition shall be given to me and to the University of Saskatchewan in any scholarly use which may be made of any material in my dissertation. Requests for permission to copy or to make other uses of materials in this dissertation in whole or part should be addressed to:
Shelterbelts provide an opportunity for carbon (C) sequestration and have the potential to mitiga... more Shelterbelts provide an opportunity for carbon (C) sequestration and have the potential to mitigate agricultural greenhouse gas (GHG) emissions. However, the influence of shelterbelts on GHG emissions at the farm scale is poorly understood. We estimated the potential of three shelterbelt tree species: hybrid poplar, white spruce, and caragana at five planting densities, to reduce GHG emissions in a model farm (cereal–pulse rotation). The Holos model, a Canadian farm-level GHG calculator developed by Agriculture and Agri-Food Canada, was used to estimate shelterbelt effects on farm GHG emissions over a 60 yr time frame. The planting densities of the shelterbelts represented 0%, 0.5%, 1.0%, 3.0%, and 5.0% of the total area of an average (688 ha) Saskatchewan farm. The greatest reduction in farm GHG emissions was estimated for hybrid poplar (23.0%) followed by white spruce (17.5%) and caragana (8.2%) — all at the highest planting density. The GHG mitigation by the shelterbelts was attr...
Centre for Northern Agroforestry and Afforestation Environmental benefits of shelterbelts on agri... more Centre for Northern Agroforestry and Afforestation Environmental benefits of shelterbelts on agricultural farmlands ❑ Shelterbelts accumulate atmospheric C in plant biomass ❑ Increase soil carbon ❑ Reduce N2O emissions due to deep roots ❑ Increase soil CH4 oxidation Knowledge gap-Changes on total farm GHG emissions due to the integration of shelterbelts is not well understood Farm location Farm Elements-Shelterbelt area, Ecotone area and Unsheltered zone
Soil moisture is known to be a major control of greenhouse gas (GHG) emissions from agricultural ... more Soil moisture is known to be a major control of greenhouse gas (GHG) emissions from agricultural soils. However, there is little data regarding GHG exchange from the organic matter-rich soils characteristic of shelterbelts-especially under elevated soil moisture conditions. In the present study, we quantified CO 2 , CH 4 and N 2 O fluxes from shelterbelts under elevated soil moisture (irrigated) and semi-arid (rainfed) conditions. Studies were carried out at the Canada-Saskatchewan Irrigation Diversification Centre (CSIDC) near Outlook, Saskatchewan. Non-steady state vented chambers were used to monitor soil GHG fluxes from three shelterbelts in 2013 and 2014. The shelterbelts consisted of a single row of caragana with a north-south orientation and a single row of Scots pine with either a north-south or east-west orientation. Each shelterbelt was divided into two areas based on whether or not it received irrigation. During the 2-year study period, N 2 O emissions from the irrigated shelterbelts (IR-SB) (0.93 kg N 2 ON ha-1) were significantly greater than those from the rainfed shelterbelts (RF-SB) (0.49 kg N 2 ON ha-1). Soil CH 4 oxidation was significantly lower in the IR-SB compared to the RF-SB (-0.85 and-1.20 kg CH 4-C ha-1 , respectively). Irrigation activities stimulated CO 2 production/emission in 2014, but had no effect on CO 2 emissions during the much drier 2013 season. Correlation analyses indicate a strong dependence of CO 2 and CH 4 fluxes on soil moisture in both IR-SB and RF-SB sites. There was a significant relationship between N 2 O emissions and soil moisture for the IR-SB sites in 2013; however, no such relationship was observed in either the IR-SB or RF-SB sites in 2014. Our study suggests that changes in precipitation patterns and soil moisture regime due to climate change could affect soil-atmosphere exchange of GHGs in shelterbelts; however, elevated soil moisture effect on GHG emissions will depend on the availability of N and C in the shelterbelts.
The influence of shelterbelts on soil properties and crop yield at various distances from the she... more The influence of shelterbelts on soil properties and crop yield at various distances from the shelterbelt have been studied; however, there are no available data detailing the spatial effects from shelterbelts into adjacent cropped fields on soil-derived greenhouse gas (GHG) emissions. The objective of this study was to quantify, for the first time, changes in soil CO 2 , CH 4 and N 2 O fluxes along replicate (n = 5) transects extending from the center of the shelterbelt to the center of the adjacent agricultural field. The shelterbelt was a 31-year-old, two-row hybrid poplar-caragana shelterbelt located in the parkland region of Saskatchewan Canada. Soil-derived GHG fluxes were measured using non-steady-state vented chambers placed along parallel transects situated within the shelterbelt strip (0H), at the shelterbelt edge (0.2H), at the edge of the adjacent cropped field (0.5H), and in the cropped field at distances of 40 m (1.5H) and 125 m (5H) from the shelterbelt. Summed over the entire study period, cumulative CO 2 emissions were greatest at 0H (8032 AE 502 kg CO 2-C ha À1) and lowest at 5H (3348 AE 329 kg CO 2-C ha À1); however, the decrease in CO 2 emissions at increasing distances away from the shelterbelt was irregular, with soil temperature and organic carbon distribution being the dominant controls. Soil CH 4 oxidation was greatest at 0H (À1447 AE 216 g CH 4-C ha À1), but decreased as distance from the shelterbelt increased. Conversely, soil N 2 O emissions were lowest at 0H (345 AE 15 g N 2 ON ha À1) but increased with increasing distance from the shelterbelt. Patterns of soil CH 4 uptake and N 2 O emissions were strongly correlated with root biomass, and soil temperature and moisture in the upper 30 cm of the soil profile. Tree root distribution may be a key factor in determining the spatial range of shelterbelt effect on GHG emissions in adjacent fields
Shelterbelts provide an opportunity for carbon (C) sequestration and have the potential to mitiga... more Shelterbelts provide an opportunity for carbon (C) sequestration and have the potential to mitigate agricultural greenhouse gas (GHG) emissions. However, the influence of shelterbelts on GHG emissions at the farm scale is poorly understood. We estimated the potential of three shelterbelt tree species: hybrid poplar, white spruce and caragana; at five planting densities, to reduce GHG emissions in a model farm (cereal-pulse rotation). The Holos model, a Canadian farm-level GHG calculator developed by Agriculture and Agri-Food Canada, was used to estimate shelterbelt effects on farm GHG emissions over a 60-year time frame. The planting densities of the shelterbelts represented 0%, 0.5%, 1.0%, 3.0% and 5.0% of the total area of an average (688 ha) Saskatchewan farm. The greatest reduction in farm GHG emissions was estimated for hybrid poplar (23.0%) followed by white spruce (17.5%) and caragana (8.2%)-all at the highest planting density. The GHG mitigation by the shelterbelts was attributable primarily (90-95% of GHG reduction) to C sequestration in tree biomass and in soil organic carbon (SOC) pools, with the remainder due to lower N 2 O, CH 4 emissions and a reduction in farm energy use. The GHG estimates from Holos agree with field measurements and suggest that species selection will be important for maximizing C sequestration and GHG mitigation potential of shelterbelt systems; conversely, shelterbelt removal from the agricultural landscape suggests an increase of on-farm GHG emissions.
Abstract Farm shelterbelts are used as a management tool to reduce erosion, conserve moisture, pr... more Abstract Farm shelterbelts are used as a management tool to reduce erosion, conserve moisture, protect crops and buildings, and sequester carbon. Although carbon storage in shelterbelts has been well researched, there have been no measurements of soil trace gas exchange in shelterbelts relative to cropped fields. Our objective was to quantify, for the first time, soil CO 2 , CH 4 and N 2 O fluxes from shelterbelts and compare them to emissions from adjacent cropped fields to assess their potential for greenhouse gas (GHG) mitigation. During 2013 and 2014, non-steady state vented chambers were used to monitor soil GHG fluxes from nine shelterbelts and their associated cropped fields at three locations within the Boreal plains and Prairies Eco-zones of Saskatchewan Canada. Mean cumulative CO 2 emissions from shelterbelt soils were significantly ( P 2 -C ha −1 yr −1 , respectively). However, soil organic carbon (SOC) storage (0–30 cm) was 27% greater – representing an increase of 28 Mg ha −1 – in the shelterbelts than in the cropped fields. Soil CH 4 oxidation was greater ( P 4 -C ha −1 yr −1 , respectively) and cropped soils emitted significantly ( P 2 O than the shelterbelts (i.e., 2.5 and 0.65 kg N 2 O-N ha −1 yr −1 , respectively). Total seasonal exchange of non-CO 2 GHGs was reduced by 0.55 Mg CO 2 e ha −1 yr −1 in shelterbelts as compared with cropped fields, 98% of which was soil-derived N 2 O. Patterns of soil temperature, moisture and organic matter distribution beneath shelterbelts suggest a modification in soil micro-environment due to shelterbelt establishment and root activity that, in turn, may be responsible for the observed increase in soil CO 2 emissions and CH 4 oxidation. Our data demonstrate that shelterbelts have substantial potential to mitigate GHGs by enhancing C storage and reducing N 2 O emissions, while maintaining a strong CH 4 sink.
In presenting this dissertation in partial fulfillment of the requirements for a Postgraduate deg... more In presenting this dissertation in partial fulfillment of the requirements for a Postgraduate degree from the University of Saskatchewan, I agree that the Libraries of this University may make it freely available for inspection. I further agree that permission for copying of this dissertation in any manner, in whole or in part, for scholarly purposes may be granted by the professor or professors who supervised my dissertation work or, in their absence, by the Head of the Department or the Dean of the College in which my dissertation work was done. It is understood that any copying or publication or use of this dissertation or parts thereof for financial gain shall not be allowed without my written permission. It is also understood that due recognition shall be given to me and to the University of Saskatchewan in any scholarly use which may be made of any material in my dissertation. Requests for permission to copy or to make other uses of materials in this dissertation in whole or part should be addressed to:
Centre for Northern Agroforestry and Afforestation Environmental benefits of shelterbelts on agri... more Centre for Northern Agroforestry and Afforestation Environmental benefits of shelterbelts on agricultural farmlands ❑ Shelterbelts accumulate atmospheric C in plant biomass ❑ Increase soil carbon ❑ Reduce N2O emissions due to deep roots ❑ Increase soil CH4 oxidation Knowledge gap-Changes on total farm GHG emissions due to the integration of shelterbelts is not well understood Farm location Farm Elements-Shelterbelt area, Ecotone area and Unsheltered zone
Soil moisture is known to be a major control of greenhouse gas (GHG) emissions from agricultural ... more Soil moisture is known to be a major control of greenhouse gas (GHG) emissions from agricultural soils. However, there is little data regarding GHG exchange from the organic matter-rich soils characteristic of shelterbelts-especially under elevated soil moisture conditions. In the present study, we quantified CO 2 , CH 4 and N 2 O fluxes from shelterbelts under elevated soil moisture (irrigated) and semi-arid (rainfed) conditions. Studies were carried out at the Canada-Saskatchewan Irrigation Diversification Centre (CSIDC) near Outlook, Saskatchewan. Non-steady state vented chambers were used to monitor soil GHG fluxes from three shelterbelts in 2013 and 2014. The shelterbelts consisted of a single row of caragana with a north-south orientation and a single row of Scots pine with either a north-south or east-west orientation. Each shelterbelt was divided into two areas based on whether or not it received irrigation. During the 2-year study period, N 2 O emissions from the irrigated shelterbelts (IR-SB) (0.93 kg N 2 ON ha-1) were significantly greater than those from the rainfed shelterbelts (RF-SB) (0.49 kg N 2 ON ha-1). Soil CH 4 oxidation was significantly lower in the IR-SB compared to the RF-SB (-0.85 and-1.20 kg CH 4-C ha-1 , respectively). Irrigation activities stimulated CO 2 production/emission in 2014, but had no effect on CO 2 emissions during the much drier 2013 season. Correlation analyses indicate a strong dependence of CO 2 and CH 4 fluxes on soil moisture in both IR-SB and RF-SB sites. There was a significant relationship between N 2 O emissions and soil moisture for the IR-SB sites in 2013; however, no such relationship was observed in either the IR-SB or RF-SB sites in 2014. Our study suggests that changes in precipitation patterns and soil moisture regime due to climate change could affect soil-atmosphere exchange of GHGs in shelterbelts; however, elevated soil moisture effect on GHG emissions will depend on the availability of N and C in the shelterbelts.
Agriculture, Ecosystems & Environment, May 1, 2016
Abstract Farm shelterbelts are used as a management tool to reduce erosion, conserve moisture, pr... more Abstract Farm shelterbelts are used as a management tool to reduce erosion, conserve moisture, protect crops and buildings, and sequester carbon. Although carbon storage in shelterbelts has been well researched, there have been no measurements of soil trace gas exchange in shelterbelts relative to cropped fields. Our objective was to quantify, for the first time, soil CO 2 , CH 4 and N 2 O fluxes from shelterbelts and compare them to emissions from adjacent cropped fields to assess their potential for greenhouse gas (GHG) mitigation. During 2013 and 2014, non-steady state vented chambers were used to monitor soil GHG fluxes from nine shelterbelts and their associated cropped fields at three locations within the Boreal plains and Prairies Eco-zones of Saskatchewan Canada. Mean cumulative CO 2 emissions from shelterbelt soils were significantly ( P 2 -C ha −1 yr −1 , respectively). However, soil organic carbon (SOC) storage (0–30 cm) was 27% greater – representing an increase of 28 Mg ha −1 – in the shelterbelts than in the cropped fields. Soil CH 4 oxidation was greater ( P 4 -C ha −1 yr −1 , respectively) and cropped soils emitted significantly ( P 2 O than the shelterbelts (i.e., 2.5 and 0.65 kg N 2 O-N ha −1 yr −1 , respectively). Total seasonal exchange of non-CO 2 GHGs was reduced by 0.55 Mg CO 2 e ha −1 yr −1 in shelterbelts as compared with cropped fields, 98% of which was soil-derived N 2 O. Patterns of soil temperature, moisture and organic matter distribution beneath shelterbelts suggest a modification in soil micro-environment due to shelterbelt establishment and root activity that, in turn, may be responsible for the observed increase in soil CO 2 emissions and CH 4 oxidation. Our data demonstrate that shelterbelts have substantial potential to mitigate GHGs by enhancing C storage and reducing N 2 O emissions, while maintaining a strong CH 4 sink.
The influence of shelterbelts on soil properties and crop yield at various distances from the she... more The influence of shelterbelts on soil properties and crop yield at various distances from the shelterbelt have been studied; however, there are no available data detailing the spatial effects from shelterbelts into adjacent cropped fields on soil-derived greenhouse gas (GHG) emissions. The objective of this study was to quantify, for the first time, changes in soil CO 2 , CH 4 and N 2 O fluxes along replicate (n = 5) transects extending from the center of the shelterbelt to the center of the adjacent agricultural field. The shelterbelt was a 31-year-old, two-row hybrid poplar-caragana shelterbelt located in the parkland region of Saskatchewan Canada. Soil-derived GHG fluxes were measured using non-steady-state vented chambers placed along parallel transects situated within the shelterbelt strip (0H), at the shelterbelt edge (0.2H), at the edge of the adjacent cropped field (0.5H), and in the cropped field at distances of 40 m (1.5H) and 125 m (5H) from the shelterbelt. Summed over the entire study period, cumulative CO 2 emissions were greatest at 0H (8032 AE 502 kg CO 2-C ha À1) and lowest at 5H (3348 AE 329 kg CO 2-C ha À1); however, the decrease in CO 2 emissions at increasing distances away from the shelterbelt was irregular, with soil temperature and organic carbon distribution being the dominant controls. Soil CH 4 oxidation was greatest at 0H (À1447 AE 216 g CH 4-C ha À1), but decreased as distance from the shelterbelt increased. Conversely, soil N 2 O emissions were lowest at 0H (345 AE 15 g N 2 ON ha À1) but increased with increasing distance from the shelterbelt. Patterns of soil CH 4 uptake and N 2 O emissions were strongly correlated with root biomass, and soil temperature and moisture in the upper 30 cm of the soil profile. Tree root distribution may be a key factor in determining the spatial range of shelterbelt effect on GHG emissions in adjacent fields
In presenting this dissertation in partial fulfillment of the requirements for a Postgraduate deg... more In presenting this dissertation in partial fulfillment of the requirements for a Postgraduate degree from the University of Saskatchewan, I agree that the Libraries of this University may make it freely available for inspection. I further agree that permission for copying of this dissertation in any manner, in whole or in part, for scholarly purposes may be granted by the professor or professors who supervised my dissertation work or, in their absence, by the Head of the Department or the Dean of the College in which my dissertation work was done. It is understood that any copying or publication or use of this dissertation or parts thereof for financial gain shall not be allowed without my written permission. It is also understood that due recognition shall be given to me and to the University of Saskatchewan in any scholarly use which may be made of any material in my dissertation. Requests for permission to copy or to make other uses of materials in this dissertation in whole or part should be addressed to:
Shelterbelts provide an opportunity for carbon (C) sequestration and have the potential to mitiga... more Shelterbelts provide an opportunity for carbon (C) sequestration and have the potential to mitigate agricultural greenhouse gas (GHG) emissions. However, the influence of shelterbelts on GHG emissions at the farm scale is poorly understood. We estimated the potential of three shelterbelt tree species: hybrid poplar, white spruce, and caragana at five planting densities, to reduce GHG emissions in a model farm (cereal–pulse rotation). The Holos model, a Canadian farm-level GHG calculator developed by Agriculture and Agri-Food Canada, was used to estimate shelterbelt effects on farm GHG emissions over a 60 yr time frame. The planting densities of the shelterbelts represented 0%, 0.5%, 1.0%, 3.0%, and 5.0% of the total area of an average (688 ha) Saskatchewan farm. The greatest reduction in farm GHG emissions was estimated for hybrid poplar (23.0%) followed by white spruce (17.5%) and caragana (8.2%) — all at the highest planting density. The GHG mitigation by the shelterbelts was attr...
Centre for Northern Agroforestry and Afforestation Environmental benefits of shelterbelts on agri... more Centre for Northern Agroforestry and Afforestation Environmental benefits of shelterbelts on agricultural farmlands ❑ Shelterbelts accumulate atmospheric C in plant biomass ❑ Increase soil carbon ❑ Reduce N2O emissions due to deep roots ❑ Increase soil CH4 oxidation Knowledge gap-Changes on total farm GHG emissions due to the integration of shelterbelts is not well understood Farm location Farm Elements-Shelterbelt area, Ecotone area and Unsheltered zone
Soil moisture is known to be a major control of greenhouse gas (GHG) emissions from agricultural ... more Soil moisture is known to be a major control of greenhouse gas (GHG) emissions from agricultural soils. However, there is little data regarding GHG exchange from the organic matter-rich soils characteristic of shelterbelts-especially under elevated soil moisture conditions. In the present study, we quantified CO 2 , CH 4 and N 2 O fluxes from shelterbelts under elevated soil moisture (irrigated) and semi-arid (rainfed) conditions. Studies were carried out at the Canada-Saskatchewan Irrigation Diversification Centre (CSIDC) near Outlook, Saskatchewan. Non-steady state vented chambers were used to monitor soil GHG fluxes from three shelterbelts in 2013 and 2014. The shelterbelts consisted of a single row of caragana with a north-south orientation and a single row of Scots pine with either a north-south or east-west orientation. Each shelterbelt was divided into two areas based on whether or not it received irrigation. During the 2-year study period, N 2 O emissions from the irrigated shelterbelts (IR-SB) (0.93 kg N 2 ON ha-1) were significantly greater than those from the rainfed shelterbelts (RF-SB) (0.49 kg N 2 ON ha-1). Soil CH 4 oxidation was significantly lower in the IR-SB compared to the RF-SB (-0.85 and-1.20 kg CH 4-C ha-1 , respectively). Irrigation activities stimulated CO 2 production/emission in 2014, but had no effect on CO 2 emissions during the much drier 2013 season. Correlation analyses indicate a strong dependence of CO 2 and CH 4 fluxes on soil moisture in both IR-SB and RF-SB sites. There was a significant relationship between N 2 O emissions and soil moisture for the IR-SB sites in 2013; however, no such relationship was observed in either the IR-SB or RF-SB sites in 2014. Our study suggests that changes in precipitation patterns and soil moisture regime due to climate change could affect soil-atmosphere exchange of GHGs in shelterbelts; however, elevated soil moisture effect on GHG emissions will depend on the availability of N and C in the shelterbelts.
The influence of shelterbelts on soil properties and crop yield at various distances from the she... more The influence of shelterbelts on soil properties and crop yield at various distances from the shelterbelt have been studied; however, there are no available data detailing the spatial effects from shelterbelts into adjacent cropped fields on soil-derived greenhouse gas (GHG) emissions. The objective of this study was to quantify, for the first time, changes in soil CO 2 , CH 4 and N 2 O fluxes along replicate (n = 5) transects extending from the center of the shelterbelt to the center of the adjacent agricultural field. The shelterbelt was a 31-year-old, two-row hybrid poplar-caragana shelterbelt located in the parkland region of Saskatchewan Canada. Soil-derived GHG fluxes were measured using non-steady-state vented chambers placed along parallel transects situated within the shelterbelt strip (0H), at the shelterbelt edge (0.2H), at the edge of the adjacent cropped field (0.5H), and in the cropped field at distances of 40 m (1.5H) and 125 m (5H) from the shelterbelt. Summed over the entire study period, cumulative CO 2 emissions were greatest at 0H (8032 AE 502 kg CO 2-C ha À1) and lowest at 5H (3348 AE 329 kg CO 2-C ha À1); however, the decrease in CO 2 emissions at increasing distances away from the shelterbelt was irregular, with soil temperature and organic carbon distribution being the dominant controls. Soil CH 4 oxidation was greatest at 0H (À1447 AE 216 g CH 4-C ha À1), but decreased as distance from the shelterbelt increased. Conversely, soil N 2 O emissions were lowest at 0H (345 AE 15 g N 2 ON ha À1) but increased with increasing distance from the shelterbelt. Patterns of soil CH 4 uptake and N 2 O emissions were strongly correlated with root biomass, and soil temperature and moisture in the upper 30 cm of the soil profile. Tree root distribution may be a key factor in determining the spatial range of shelterbelt effect on GHG emissions in adjacent fields
Shelterbelts provide an opportunity for carbon (C) sequestration and have the potential to mitiga... more Shelterbelts provide an opportunity for carbon (C) sequestration and have the potential to mitigate agricultural greenhouse gas (GHG) emissions. However, the influence of shelterbelts on GHG emissions at the farm scale is poorly understood. We estimated the potential of three shelterbelt tree species: hybrid poplar, white spruce and caragana; at five planting densities, to reduce GHG emissions in a model farm (cereal-pulse rotation). The Holos model, a Canadian farm-level GHG calculator developed by Agriculture and Agri-Food Canada, was used to estimate shelterbelt effects on farm GHG emissions over a 60-year time frame. The planting densities of the shelterbelts represented 0%, 0.5%, 1.0%, 3.0% and 5.0% of the total area of an average (688 ha) Saskatchewan farm. The greatest reduction in farm GHG emissions was estimated for hybrid poplar (23.0%) followed by white spruce (17.5%) and caragana (8.2%)-all at the highest planting density. The GHG mitigation by the shelterbelts was attributable primarily (90-95% of GHG reduction) to C sequestration in tree biomass and in soil organic carbon (SOC) pools, with the remainder due to lower N 2 O, CH 4 emissions and a reduction in farm energy use. The GHG estimates from Holos agree with field measurements and suggest that species selection will be important for maximizing C sequestration and GHG mitigation potential of shelterbelt systems; conversely, shelterbelt removal from the agricultural landscape suggests an increase of on-farm GHG emissions.
Abstract Farm shelterbelts are used as a management tool to reduce erosion, conserve moisture, pr... more Abstract Farm shelterbelts are used as a management tool to reduce erosion, conserve moisture, protect crops and buildings, and sequester carbon. Although carbon storage in shelterbelts has been well researched, there have been no measurements of soil trace gas exchange in shelterbelts relative to cropped fields. Our objective was to quantify, for the first time, soil CO 2 , CH 4 and N 2 O fluxes from shelterbelts and compare them to emissions from adjacent cropped fields to assess their potential for greenhouse gas (GHG) mitigation. During 2013 and 2014, non-steady state vented chambers were used to monitor soil GHG fluxes from nine shelterbelts and their associated cropped fields at three locations within the Boreal plains and Prairies Eco-zones of Saskatchewan Canada. Mean cumulative CO 2 emissions from shelterbelt soils were significantly ( P 2 -C ha −1 yr −1 , respectively). However, soil organic carbon (SOC) storage (0–30 cm) was 27% greater – representing an increase of 28 Mg ha −1 – in the shelterbelts than in the cropped fields. Soil CH 4 oxidation was greater ( P 4 -C ha −1 yr −1 , respectively) and cropped soils emitted significantly ( P 2 O than the shelterbelts (i.e., 2.5 and 0.65 kg N 2 O-N ha −1 yr −1 , respectively). Total seasonal exchange of non-CO 2 GHGs was reduced by 0.55 Mg CO 2 e ha −1 yr −1 in shelterbelts as compared with cropped fields, 98% of which was soil-derived N 2 O. Patterns of soil temperature, moisture and organic matter distribution beneath shelterbelts suggest a modification in soil micro-environment due to shelterbelt establishment and root activity that, in turn, may be responsible for the observed increase in soil CO 2 emissions and CH 4 oxidation. Our data demonstrate that shelterbelts have substantial potential to mitigate GHGs by enhancing C storage and reducing N 2 O emissions, while maintaining a strong CH 4 sink.
Uploads
Papers by Chukwudi Amadi