Do these plants need water?
(irrigation water)
Shock, Feibert, Saunders, Shaw
Why do we care about seed for
revegetation? Share a concern about the
cumulative effects of Euro-American
cultural influences on natural landscapes.
Why
irrigate?
SDI Objectives
Test SDI for stable, efficient
native wildflower seed
production using small
amounts of supplemental
irrigation water.
Why try SDI irrigation?
1. Cultivated seed production
requires dependable production.
2. Excess water stress hurts
flowering and seed set.
3. Total water requirements are
unknown, but probably are low.
4. Furrow and sprinkler irrigation
encourage weeds and disease.
Design
Drip tape buried 0.3 m (1 ft) deep
Tape 1.52 m (5 ft) apart
T-tape TSX 515-16-340
0.76-m beds, seed drilled 0.38 m
(15 in) to each side of the tape
Forbs established in 2005, 2006
0.04 ha each of 7 Species
E. umbellatum, Sulfur-flower buckwheat
Penstemon deustus, Hotrock penstemon
P. speciosus, Showy penstemon
P. acuminatus, Sharpleaf penstemon
Lomatium grayi, Gray biscuitroot
L. dissectum, Fernleaf biscuitroot
L. triternatum, Nineleaf biscuitroot
2007 trial, 6 added species
Sphaeralcea coccinea, Red globemallow
S. parvifolia, Small flower globemallow
S. grossularifolia, Gooseberryleaf
globemallow
Dalea searlsiae, Seals’ prairie clover
Dalea ornata, Western prairie clover
Astragalus filipes, Basalt milkvetch
Design
Irrigated at 0, 1, and 2 ac-in/ac
every 2 weeks, RCBD 4 rep.
Flowering to seed set
Water meters to verify water
applied
Neutron probe to measure soil
water
Rainfall
Rainfall for the 2006, 2007,
and 2008 crop seasons from
the preceding October
through June totaled 15.89,
6.24, and 6.18 inches
respectively.
Case 1, no response
Sphaeralcea parvifolia
Sphaeralcea grossulariifolia
Sphaeralcea coccinea
Dalea searlsiae
Dalea ornata
Astragalus filipes
Penstemon deustus
Lomatium dissectum
Penstemon deustus
Hotrock penstemon
Effect of SDI rate on the seed yield
of Penstemon deutus, Ontario, OR.
None
1"/two wks
2"/two wks
Seed yield, lb/acre
1250
1000
750
500
250
0
2006
2007
Case 2, need 4-5 inches/yr
Penstemon acuminatus
Penstemon speciosus
Penstemon speciosus
Royal or Sagebrush
penstemon
Royal penstemon average seed yields over three
years in response to subsurface drip irrigation.
Seed yield, lb/acre
300
200
100
Y = 83.9 + 58.6X - 6.06X 2
R2 = 0.57, P = 0.05
0
0
4
Total water applied, inches
8
Case 3, need 7-8 inches/yr
Eriogonum umbellatum
Lomatium dissectum
Lomatium triternatum
Lomatium triternatum
Nineleaf biscuitroot
Lomatium triternatum
2007
Average
2008
Seed yield, lb/acre
2000
Y = 195.3 + 283.9X - 16.9X 2
R2 = 0.77, P = 0.01
1500
1000
Y = 98.8 + 144.2X - 8.5X 2
R2 = 0.77, P = 0.01
500
0
Y = 3.26 + 3.06X
R2 = 0.52, P = 0.01
0
4
Total water applied, inches
8
Seed yield of Lomatium grayi in response
to subsurface drip irrigation
2007
2008
Average
Seed yield, lb/acre
2000
Y = 393.3 + 315.4X - 23.0X 2
R2 = 0.93, P = 0.001
1500
Y = 214.7 + 164.8X - 11.6X 2
R2 = 0.89, P = 0.001
1000
500
0
Y =37.5 + 12.0.X
R2 = 0.26, P = 0.10
0
4
Total water applied, inches
8
Eriogonum umbellatum
Sulfur-flower buckwheat
Three year average seed yield sulfur-flower
buckwheat with subsurface drip irrigation.
Seed yield, lb/acre
400
300
200
Y = 111.4 + 20.5X
R2 = 0.87, P = 0.001
100
0
0
4
Total water applied, inches
8
SDI Conclusions
1. SDI worked well for irrigation and
weed pressure.
2. Case 1. No irrigation response.
Species with imperfect stands had
inconsistent irrigation responses.
Lomatium dissectum suffered
disease and has not flowered.
SDI Conclusions
3. Case 2. Response to 4-5 inches/yr.
Penstemon specious and P.
acuminatus,
acuminatus no response in 2006,
4-5” in 2007 and 2008.
4. Case 3. Response to 7-8 inches/yr.
Lomatium triternatum and L. grayi,
grayi
4 to 8” in 2007 and 2008.
Eriogonum umbellatum responded
to 8” in 2006, 2007, and 2008.
Thank you!