Cultural Practices for Native Forb
Seed
Production
Oregon State
University, Malheur Exp. Sta. Ontario
Authors
Clint Shock, Erik Feibert, M. Saunders
Joey Ishida, and Corey Ransom
Why try SDI irrigation?
1. Cultivated seed production
requires dependable production.
2. Excess water stress has hurts
flowering and seed set.
3. Total water requirements are
unknown, but probably are low.
4. Furrow and sprinkler irrigation
encourage weeds and disease.
Objectives
Test SDI for stable, efficient
native forb seed production
using small amounts of
supplemental irrigation water.
1/10 acre of 7 Species
E. umbellatum, Sulfur-flower buckwheat
P. acuminatus, Sand penstemon
P. deustus, Hot rock penstemon
P. speciosus, Showy penstemon
Lomatium grayi, Gray biscuitroot
L. dissectum, Fernleaf biscuitroot
L. triternatum, Nineleaf biscuitroot
Design
Drip tape burried 12 inches deep
Tape 5 feet apart
T-tape TSX 515-16-340
30-inch beds, seed drilled 15” to
each side of the tape
Forbs established in 2005 using
5.5”, for 2006 0, 4.8, 8.7 inches.
Typical and actual rainfall
2005 - 2006
average
Precipitation (inches)
4
3
2
1
0
Oct Nov Dec Jan Feb Mar Apr May Jun Jul
Penstemon acuminatus
Sand penstemon
Soil water content for the 0 - 36 inch depth for
Volumetric water content, %
Penstemon acuminatum
2 in
1 in
0 in
30
25
20
harvest
flowering ends
15
10
138
153
156
Day of year
179
187
Seed yield in response to irrigation for
Penstemon acuminatum
Seed yield (lb/acre)
700
600
500
400
300
200
100
0
8.7 in
4.8 in
Water applied in 4 irrigations
0 in
Penstemon speciosus
Royal or Sagebrush penstemon
Soil water content at the 0 - 36 inch depth for
Volumetric water content, %
Penstemon speciosus
2 in
1 in
0 in
30
25
20
mid flowering
15
10
138
153
156
Day of year
179
187
Seed yield in response to irrigation for
Penstemon speciosus
Seed yield (lb/acre)
300
200
100
0
8.7 in
4.8 in
Water applied in 4 irrigations
0 in
Penstemon deustus
Hotrock penstemon
Seed yield in response to irrigation for
Penstemon deustus
Seed yield (lb/acre)
1400
1200
1000
800
600
400
200
0
8.7 in
4.8 in
Water applied in 4 irrigations
0 in
Eriogonum umbellatum
Sulfur buckwheat
Soil water content at the 0 - 36 inch depth for
Volumetric water content, %
Eriogonum umbellatum
2 in
1 in
0 in
30
25
20
flowering starts
15
10
138
153
156
Day of year
179
187
Seed yield in response to irrigation for
Eriogonum umbellatum
Seed yield (lb/acre)
400
a
300
b
200
b
100
0
8.7 in
4.8 in
Water applied in 4 irrigations
0 in