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Boise, Idaho
Annual March - May
Stuart Hardegree, Corey Moffet, Christine Walters and Roger Sheley - - PowerPoint PPT Presentation
Stuart Hardegree, Corey Moffet, Christine Walters and Roger Sheley - - PowerPoint PPT Presentation
Stuart Hardegree, Corey Moffet, Christine Walters and Roger Sheley USDA Agricultural Research Service Annual Boise, Idaho March - May Seed Germinated seed Emerged seedling Juvenile Adult Established seedling 70 30 60 25 Precipitation
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Germinated seed Emerged seedling Seed Established seedling Juvenile Adult
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Seeding Establishment Survival Temperature ( C)
- 5
5 10 15 20 25 30
Month
Oct Nov Dec Jan Feb Mar Apr May June Jul Aug Sep
Precipitation (mm)
10 20 30 40 50 60 70
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Germinated seed Emerged seedling Seed Established seedling Juvenile Adult
W E A T H E R
Rapid
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Good Fall Weather Temperature ( C)
- 5
5 10 15 20 25 30
Month
Oct Nov Dec Jan Feb Mar Apr May June Jul Aug Sep
Precipitation (mm)
10 20 30 40 50 60 70
Bad Seedling Emergence
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Seedbed microclimatic modelling Hydrothermal germination response modelling
What would have happened if we planted any day in the last 44 years?
- 5 planting dates, Oct 1 – Nov 26
- Cumulative germination (whole seed population)
- Potential distribution of post-germination freezing/drought
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13 seedlots
- Cheatgrass (Bromus tectorum)
- Bluebunch Wheatgrass (Pseudoroegneria spicata)
- Bottlebrush Squirreltail (Elymus elymoides)
- Big Squirreltail (Elymus multisetus)
- Thickspike Wheatgrass (Elymus lanceolatus)
- Sandberg Bluegrass (Poa secunda)
- Idaho Fescue (Festuca idahoensis)
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Hydrothermal Germination Response
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Germination Rate (d-1)
Hydrothermal Model
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Germination Rate (d-1)
Hydrothermal Model
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Germination Rate (d-1)
Hydrothermal Model
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R =1 and germination occurs R(year, season) = #times expected to germinate R(year, season) = relative favorability of microclimate R(year, season) = Ranking mechanism to compare years, species, treatment scenarios, forecast scenarios, etc.
Soil Temperature Water Potential Hydro-Thermal Model
Ecological Index for Establishment/Site Favorability
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Day Planted
50 100 150 200 250 300 350
Cumulative Germination (%)
20 40 60 80 100 Pulses of favorability for germination
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Day of Year
01-Oct 29-Oct 26-Nov 24-Dec 21-Jan 18-Feb 18-Mar 15-Apr 13-May 10-Jun 08-Jul 05-Aug 02-Sep 30-Sep
Probability Day Drops Below 0 C (%)
20 40 60 80 100
Probability Day Drops Below -1.5 MPa (%)
Probability distribution of post-germination mortality
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Days to Germinate
50 100 150 200 250 300 350
Cumulative Germination (%)
20 40 60 80 100
Days to Germinate
50 100 150 200 250 300 350
Cumulative Germination (%)
20 40 60 80 100
Days to Germinate
50 100 150 200 250 300 350
Cumulative Germination (%)
20 40 60 80 100
Days to Germinate
50 100 150 200 250 300 350
Cumulative Germination (%)
20 40 60 80 100
Days to Germinate
50 100 150 200 250 300 350
Cumulative Germination (%)
20 40 60 80 100
October 1 October 15 October 29 November 26 November 12
All germinate in fall All avoidance FEID avoidance
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Seeding Potential Germination, Pre-emergent Mortality Temperature ( C)
- 5
5 10 15 20 25 30
Month
Oct Nov Dec Jan Feb Mar Apr May June Jul Aug Sep
Precipitation (mm)
10 20 30 40 50 60 70
Establishment Survival
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Cheatgrass vs native seed “germination” = apples and oranges
- Present from previous spring vs seeded
- 1,000-20,000/m2 vs 250-500/m2
- Stress => set seed
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Conclusions
- Post-germination/pre-emergent mortality bottleneck
- Germination a lot faster than you think. Fall germination
probable if you plant early.
- Cheatgrass rate advantage not always relevant; cheatgrass
seed numbers always relevant
- Large effect of planting date even within 8 week fall interval
- Late fall planting can see germination-rate syndrome effects
- Management options:
- Plant late in fall season
- Plant in winter/spring (not feasible)
- Plant often (not feasible)
- Artificial induction of rate variability
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John Abatzoglou Alex Boehm Cynthia Brown Mark Brunson Jeanne Chambers Matt Germino Nancy Glenn Anne Halford Katherine Hegewisch Jeremy James Gwendwr Meredith Corey Moffet Tom Monaco Génie MontBlanc Mike Pellant David Pilliod Bruce Roundy Nancy Shaw Roger Sheley Tony Svejcar Justin Welty
GBRMP
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