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 (mm) Temperature ( C) 50 20 40 15 30 10 20 5 10 0 0 -5 Oct Nov Dec Jan Feb Mar Apr May June Jul Aug Sep Month Seeding Establishment Survival

W E A T H E R Rapid Seed Germinated seed Emerged seedling Juvenile Adult Established seedling

70 30 60 25 Precipitation (mm) Temperature ( C) 50 20 40 15 30 10 20 5 10 0 0 -5 Oct Nov Dec Jan Feb Mar Apr May June Jul Aug Sep Month Good Bad Fall Seedling Weather Emergence

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

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 )

Hydrothermal Germination Response

Germination Rate (d -1 ) Hydrothermal Model

Germination Rate (d -1 ) Hydrothermal Model

Germination Rate (d -1 ) Hydrothermal Model

Ecological Index for Establishment/Site Favorability Soil Temperature Hydro-Thermal Model Water Potential 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.

Pulses of favorability for germination 100 Cumulative Germination (%) 80 60 40 20 0 0 50 100 150 200 250 300 350 Day Planted

Probability distribution of post-germination mortality 100 Probability Day Drops Below -1.5 MPa (%) Probability Day Drops Below 0 C (%) 80 60 40 20 0 01-Oct 29-Oct 26-Nov 13-May 08-Jul 24-Dec 21-Jan 18-Feb 18-Mar 15-Apr 10-Jun 05-Aug 02-Sep 30-Sep Day of Year

October 1 100 Cumulative Germination (%) 80 60 40 October 15 100 20 Cumulative Germination (%) 80 0 0 50 100 150 200 250 300 350 Days to Germinate 60 40 October 29 100 20 Cumulative Germination (%) 80 0 0 50 100 150 200 250 300 350 Days to Germinate 60 40 November 12 100 20 All germinate in fall Cumulative Germination (%) 80 0 0 50 100 150 200 250 300 350 Days to Germinate 60 40 November 26 100 20 FEID avoidance Cumulative Germination (%) 80 0 0 50 100 150 200 250 300 350 Days to Germinate 60 40 20 All avoidance 0 0 50 100 150 200 250 300 350 Days to Germinate

70 30 60 25 Precipitation (mm) Temperature ( C) 50 20 40 15 30 10 20 5 10 0 0 -5 Oct Nov Dec Jan Feb Mar Apr May June Jul Aug Sep Month Seeding Establishment Survival Potential Germination, Pre-emergent Mortality

Cheatgrass vs native seed “germination” = apples and oranges • Present from previous spring vs seeded 1,000-20,000/m 2 vs 250-500/m 2 • • Stress => set seed

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

GBRMP John Abatzoglou Corey Moffet Alex Boehm Tom Monaco Cynthia Brown Génie MontBlanc Mark Brunson Mike Pellant Jeanne Chambers David Pilliod Matt Germino Bruce Roundy Nancy Glenn Nancy Shaw Anne Halford Roger Sheley Katherine Hegewisch Tony Svejcar Jeremy James Justin Welty Gwendwr Meredith

The preceding presentation was delivered at the 2017 National Native Seed Conference Washington, D.C. February 13-16, 2017 This and additional presentations available at http://nativeseed.info