1. Sub- irrigation of perennial forage Based Dairy system March 16, 2017
A. Fredeen, P. Havard, Y. Papadopoulos, T. Bouman,
S. Kulshreshtha, E. Yiridoe, C. Madramootoo
Dalhousie University, Truro, NS;
AAFC, Troro, NS;
University of Cape Breton, Sydney;
University of Saskatchewan, SK;
Macdonald College, McGill St. Anne de Bellevue, QU. ,

2. Experiment 2012- 2015 d-2 sid-2 d-1 Sid-1 none- 2 none-1
Sub- recycling irrigation/ drainage under perennial forage Harvested by mob- grazing (5x/season) GHG flux measured on the field (manure only) Plant and animal productivity
d sid d-1
Sid-1
none- 2 none-1
Pump
Reservoir
Figure 1. Field layout

3. Non-Irrigated 4 b
Irrigated 3 b
Non-Irrigated 2 a
Irrigated 1 a
Natural b Natural a
Gate
Permantent Electric Fencing
Water line
Instruments/fencing
Water bin
Temporary Fencing

4. Results Table 1. effect of irrigation and day; Probability
Source of variation
Milk yield
Kg/ d
ECM
N2O
g/ d
CH4
CO2
Irrigation
0.30
0.94
0.06
0.81
0.25
Day
0.001
Day*Irrigation
0.999
0.15
0.04

5. Figure 3. Treatment effect on N2O emission

6. GHG Balance, CO2 equiv/ 4 mo & milk yield on 41ha field
15.5t CH4
Up to 80t C1 1t
N2O
73t milk
4.1 ha
1Ghimiro, 2014

7. Gaps
Perennial forage can completely offset GHG production in dairy ystems1 but the effects of irrigation on SOC storage are unknown.
Heightened irrigation/ severity of flooding needed
Rate of SOC accumulation ?
Extent of fertigation?
Socio-economic impact? Soussanna et al.
1Soussana

8. Objective AGGPII
To evaluate the profitability of SID & effects on GHG offset from perennial forage.
… effects on:
Soil C accumulation
Agronomic productivity,
Socio-economics

9. Method
3 trt x 2 rep: - Continual SID Drainage - Neither Repeated variables: Forage yield Forage quality Potential milk yield SOC

10. SOC Measurement
Rhizosphere level
and surface
3x/ y