Nitrogen Rate Cumulative N2 O Emissions 4R Nitrogen ... · 4R Nitrogen Management and N 2 O...
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4R Nitrogen Management and N 2 O Emissions for Irrigated Potato Production in Manitoba Kevin Baron 1 , Sally Parsonage 1 , Dale Tomasiewicz 2 , Ramona Mohr 3 , and Mario Tenuta 1 1 Department of Soil Science, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2 2 Agriculture and Agri-Food Canada, Outlook, Saskatchewan, Canada S0L 2N0 3 Agriculture and Agri-Food Canada, Brandon, Manitoba, Canada R7A 5Y3 Objective Materials and Methods To determine the influence of 4R nitrogen management practices, including changes in rate, source and timing, on seasonal and cumulative nitrous oxide (N 2 O) emissions from irrigated potato production in Manitoba. We thank members of the Soil Ecology Laboratory and CMCDC Carberry Manitoba and Dr. Alison Nelson for assistance and acknowledge funding by Agriculture and Agri-Food Canada and the following sponsors: Results Over the 2011 and 2012 growing seasons independent nitrogen placement and nitrogen application timing field trials were established at the Canada-Manitoba Crop Diversification Centre (CMCDC) located near Carberry, Manitoba. All studies were conducted on clay-loam (on-site) or sandy loam (off-site) soils typical of those supporting commercial potato production in Manitoba. For the nitrogen placement study, nitrogen treatments of 100 or 200 kg N ha -1 as urea or ESN were pre-plant broadcast incorporated or banded at the time of seeding. For the nitrogen application timing study nitrogen treatments of 180 kg N ha -1 were applied as combinations of pre-plant broadcast incorporation, split application or fertigation (Table 1). All trials were planted to the Russet Burbank cultivar, received blanket applications of additional fertilizer (non-N) to meet crop P, K and S demands. For nitrous oxide (N 2 O) measurements four static-vented chambers were deployed to each plot with two on the hill and two on the furrow. For both studies four replicate plots per nitrogen treatment were monitored. Emissions were estimated by examining the rate of increase in N 2 O concentration over a 60 minute interval, with N 2 O concentrations measured by gas chromatography. Figure 1. Field operations associated with studies evaluating greenhouse gas (GHG) emissions from irrigated potato production in Manitoba. In spite of high N inputs required of irrigated potato production in Manitoba, cumulative N 2 O emissions are comparable to rates measured in rain-fed cropping systems, suggesting current IPCC Tier II values for irrigated cropland may require modification. For both ESN™ and urea, banding appeared superior to broadcast incorporation as a N 2 O mitigation strategy. In both 2011 and 2012, urea or ESN™ broadcast and incorporated in the nitrogen placement study emerged as treatments with the highest cumulative seasonal N 2 O emissions. In the nitrogen application timing study, split applications of urea or fertigation produced the lowest cumulative seasonal N 2 O emissions over controls. In both 2011 and 2012 cumulative emissions from upfront applications of ESN™ or urea applied at planting consistently exceeded emissions from split applications of urea or fertigation. Amongst 4R nitrogen management practices, changes in nitrogen application timing appeared to hold the greatest potential towards mitigating N 2 O emission in irrigated potatoes. In Manitoba, future studies evaluating greenhouse gas emissions from irrigated potato production may be focused on direct and indirect N 2 O emissions from fine-textured or tile-drained fields. Acknowledgements: Background Conclusions Irrigated potatoes are one of the most intensively managed crops in Manitoba, requiring large inputs of synthetic N fertilizer (> 200 kg N ha -1 ) to maximize yield potential. Applications of synthetic N fertilizer also increase soil NH 4 + and NO 3 - levels, which increase the potential for soils to emit nitrous oxide (N 2 O), a potent greenhouse gas. Current IPCC Tier II values in Canada estimate irrigated cropland will emit more N 2 O than rain-fed cropping systems. However, limited regional studies are available to characterize greenhouse gas emissions from irrigated potato production across the Canadian Prairies. Table 1. Fertilizer treatments applied to complementary field trials evaluating 4R nitrogen management practices applied to irrigated potato production in Manitoba. N 2 O Emissions (g ha -1 d -1 ) Cumulative N 2 O Emissions (kg N 2 O ha -1 ) Cumulative N 2 O Emissions (kg N 2 O ha -1 ) Nitrogen Placement Study Nitrogen Application Timing Study 2011 2012 2011 Nitrogen Application Timing Study Nitrogen Placement Study 2012 2011 N 2 O Emissions (g ha -1 d -1 ) 2012 2011 Day of Year Day of Year 2012 Day of Year Day of Year 2012 2011 2012 Table 2. Summary ANOVA (analysis of variance) table for cumulative seasonal N 2 O emissions from treatments in the nitrogen placement study over the 2011 and 2012 growing seasons. Table 3. Summary ANOVA (analysis of variance) table for cumulative seasonal N 2 O emissions from treatments in the nitrogen application timing study over the 2011 and 2012 growing seasons. Within and between years treatments followed by different letter groupings are significantly different according to Fisher’s protected LSD (P< 0.05) Within and between years treatments followed by different letter groupings are significantly different according to Fisher’s protected LSD (P< 0.05) Urea 180 PP Nitrogen Rate kg N 2 O-N ha -1 Treatment kg N ha -1 2011 2012 Avg. Control 0 0.30b 0.22a 0.26c Urea 180 PP 180 1.15a 0.78a 0.96a ESN 180 PP 180 1.21a 0.43a 0.82ab Urea 120-60 SP 180 0.48b 0.28a 0.38bc Fert 60-45-75 180 0.70ab 0.28a 0.49abc Fert 90-45-45 180 0.80ab 0.41a 0.61abc Avg. 0.78A 0.40B Analysis of variance Sources df Pr ≥ F N treatment 5 0.0114 Year 1 0.0028 N Treatment x Year 5 ns Cumulative N 2 O Emissions Control Control ESN 180 PP ESN Broadcast 200 Control Control Urea Broadcast 200 Nitrogen Rate kg N 2 O-N ha -1 Treatment kg N ha -1 2011 2012 Avg. Control 0 0.82c 0.15c 0.48b Urea Broadcast 200 3.20a 0.69b 1.94a Urea Banded 200 2.34ab 0.49b 1.54a ESN Broadcast 100 2.39ab 0.39bc 1.39ab ESN Broadcast 200 2.79ab 1.32a 2.06a ESN Banded 100 1.60bc 0.56bc 1.31ab ESN Banded 200 2.79ab 0.58bc 1.39ab Avg. 2.17A 0.63B Analysis of variance Sources df Pr ≥ F N treatment 6 0.0001 Year 1 <0.0001 N Treatment x Year 6 ns Cumulative N 2 O Emissions Treatment Source Total N Rate Placement Broadcast Broadcast Fertigation (kg N ha -1 ) Pre-Plant Hilling Intervals 1 Control 0 0 0 0 2 Urea 180 Broadcast 120 60 - 3 Urea 180 Broadcast 180 - - 4 ESN 180 Broadcast 180 - - 5 Urea + UAN 180 Broadcast 90 45 20-15-10-0 Fertigation 6 Urea + UAN 180 Broadcast 60 45 30-20-15-10 Fertigation ------------------ N Rate (kg N ha -1 ) ------------------ Treatment Source Total N Rate Placement kg N ha -1 1 Control 0 2 Urea 100 Broadcast 3 Urea 200 Broadcast 4 Urea 100 Banding (In-hill) 5 Urea 200 Banding (In-hill) 6 ESN 100 Broadcast 7 ESN 200 Broadcast 8 ESN 100 Banding (In-hill) 9 ESN 200 Banding (In-hill)
Transcript of Nitrogen Rate Cumulative N2 O Emissions 4R Nitrogen ... · 4R Nitrogen Management and N 2 O...
4R Nitrogen Management and N2O Emissions for Irrigated Potato Production in Manitoba
Kevin Baron1, Sally Parsonage1, Dale Tomasiewicz2, Ramona Mohr3, and Mario Tenuta1
1Department of Soil Science, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N22Agriculture and Agri-Food Canada, Outlook, Saskatchewan, Canada S0L 2N0
3Agriculture and Agri-Food Canada, Brandon, Manitoba, Canada R7A 5Y3
Objective
Materials and Methods
To determine the influence of 4R nitrogen management practices,
including changes in rate, source and timing, on seasonal and
cumulative nitrous oxide (N2O) emissions from irrigated potato
production in Manitoba.
We thank members of the Soil Ecology Laboratory and CMCDC Carberry
Manitoba and Dr. Alison Nelson for assistance and acknowledge funding by
Agriculture and Agri-Food Canada and the following sponsors:
Results
Over the 2011 and 2012 growing seasons independent nitrogen placement and nitrogen application timing
field trials were established at the Canada-Manitoba Crop Diversification Centre (CMCDC) located near
Carberry, Manitoba. All studies were conducted on clay-loam (on-site) or sandy loam (off-site) soils typical of
those supporting commercial potato production in Manitoba. For the nitrogen placement study, nitrogen
treatments of 100 or 200 kg N ha-1 as urea or ESN were pre-plant broadcast incorporated or banded at the time
of seeding. For the nitrogen application timing study nitrogen treatments of 180 kg N ha-1 were applied as
combinations of pre-plant broadcast incorporation, split application or fertigation (Table 1). All trials were
planted to the Russet Burbank cultivar, received blanket applications of additional fertilizer (non-N) to meet crop
P, K and S demands. For nitrous oxide (N2O) measurements four static-vented chambers were deployed to
each plot with two on the hill and two on the furrow. For both studies four replicate plots per nitrogen treatment
were monitored. Emissions were estimated by examining the rate of increase in N2O concentration over a 60
minute interval, with N2O concentrations measured by gas chromatography.
Figure 1. Field operations associated with studies evaluating greenhouse gas (GHG) emissions from irrigated potato production in Manitoba.
In spite of high N inputs required of irrigated potato production in
Manitoba, cumulative N2O emissions are comparable to rates
measured in rain-fed cropping systems, suggesting current IPCC
Tier II values for irrigated cropland may require modification.
For both ESN™ and urea, banding appeared superior to
broadcast incorporation as a N2O mitigation strategy.
In both 2011 and 2012, urea or ESN™ broadcast and
incorporated in the nitrogen placement study emerged as
treatments with the highest cumulative seasonal N2O emissions.
In the nitrogen application timing study, split applications of urea
or fertigation produced the lowest cumulative seasonal N2O
emissions over controls.
In both 2011 and 2012 cumulative emissions from upfront
applications of ESN™ or urea applied at planting consistently
exceeded emissions from split applications of urea or fertigation.
Amongst 4R nitrogen management practices, changes in nitrogen
application timing appeared to hold the greatest potential towards
mitigating N2O emission in irrigated potatoes.
In Manitoba, future studies evaluating greenhouse gas emissions
from irrigated potato production may be focused on direct and
indirect N2O emissions from fine-textured or tile-drained fields.
Acknowledgements:
Background
Conclusions
Irrigated potatoes are one of the most intensively managed
crops in Manitoba, requiring large inputs of synthetic N fertilizer
(> 200 kg N ha-1) to maximize yield potential.
Applications of synthetic N fertilizer also increase soil NH4+ and
NO3- levels, which increase the potential for soils to emit nitrous
oxide (N2O), a potent greenhouse gas.
Current IPCC Tier II values in Canada estimate irrigated
cropland will emit more N2O than rain-fed cropping systems.
However, limited regional studies are available to characterize
greenhouse gas emissions from irrigated potato production
across the Canadian Prairies.
Table 1. Fertilizer treatments applied to complementary field trials evaluating 4R nitrogen management practices applied to irrigated potato production in Manitoba.
N2O
Em
issi
on
s (g
ha-1
d-1
)
Cu
mu
lati
ve N
2O
Em
issi
on
s (k
g N
2O
ha-1
)C
um
ula
tive
N2O
Em
issi
on
s (k
g N
2O
ha-1
)
Nitrogen Placement Study
Nitrogen Application Timing Study2011
2012
2011
Nitrogen Application Timing Study
Nitrogen Placement Study
2012
2011
N2O
Em
issi
on
s (g
ha-1
d-1
)
2012
2011
Day of Year Day of Year
2012
Day of Year Day of Year
2012
2011
2012
Table 2. Summary ANOVA (analysis of variance) table for cumulative seasonal N2O emissions from treatments in the nitrogen placement study over the 2011 and 2012 growing seasons.
Table 3. Summary ANOVA (analysis of variance) table for cumulative seasonal N2O emissions from treatments in the nitrogen application timing study over the 2011 and 2012 growing seasons.
Within and between years treatments followed by different letter groupings are significantly different according to Fisher’s protected LSD (P< 0.05)
Within and between years treatments followed by different letter groupings are significantly different according to Fisher’s protected LSD (P< 0.05)
Urea 180 PP
Nitrogen Rate
kg N2O-N ha-1
Treatment kg N ha-1 2011 2012 Avg.
Control 0 0.30b 0.22a 0.26c
Urea 180 PP 180 1.15a 0.78a 0.96a
ESN 180 PP 180 1.21a 0.43a 0.82ab
Urea 120-60 SP 180 0.48b 0.28a 0.38bc
Fert 60-45-75 180 0.70ab 0.28a 0.49abc
Fert 90-45-45 180 0.80ab 0.41a 0.61abc
Avg. 0.78A 0.40B
Analysis of variance
Sources df Pr ≥ F
N treatment 5 0.0114
Year 1 0.0028
N Treatment x Year 5 ns
Cumulative N2O Emissions
Control
Control
ESN 180 PP
ESN Broadcast 200
Control
Control
Urea Broadcast 200
Nitrogen Rate
kg N2O-N ha-1
Treatment kg N ha-1 2011 2012 Avg.
Control 0 0.82c 0.15c 0.48b
Urea Broadcast 200 3.20a 0.69b 1.94a
Urea Banded 200 2.34ab 0.49b 1.54a
ESN Broadcast 100 2.39ab 0.39bc 1.39ab
ESN Broadcast 200 2.79ab 1.32a 2.06a
ESN Banded 100 1.60bc 0.56bc 1.31ab
ESN Banded 200 2.79ab 0.58bc 1.39ab
Avg. 2.17A 0.63B
Analysis of variance
Sources df Pr ≥ F
N treatment 6 0.0001
Year 1 <0.0001
N Treatment x Year 6 ns
Cumulative N2O Emissions
Treatment Source Total N Rate Placement Broadcast Broadcast Fertigation
(kg N ha-1) Pre-Plant Hilling Intervals
1 Control 0 0 0 0
2 Urea 180 Broadcast 120 60 -
3 Urea 180 Broadcast 180 - -
4 ESN 180 Broadcast 180 - -
5 Urea + UAN 180 Broadcast 90 45 20-15-10-0
Fertigation
6 Urea + UAN 180 Broadcast 60 45 30-20-15-10
Fertigation
------------------ N Rate (kg N ha-1) ------------------
Treatment Source Total N Rate Placement
kg N ha-1
1 Control 0
2 Urea 100 Broadcast
3 Urea 200 Broadcast
4 Urea 100 Banding (In-hill)
5 Urea 200 Banding (In-hill)
6 ESN 100 Broadcast
7 ESN 200 Broadcast
8 ESN 100 Banding (In-hill)
9 ESN 200 Banding (In-hill)
