By Tony White, Ph.D.
The Intermountain Region of the Western United States is riddled with jointed goatgrass. Growers in this area, consisting of Utah and Southern Idaho, are nearing their wits end with this weed and are rapidly searching for alternative control methods. Scientists at Utah State University have stepped up to develop new ways to battle this troublesome weed.
Dr. Jack Evans, Weed Scientist at Utah State University, has evaluated the effects of including safflower in a Wheat-Fallow (W-F) cropping system at the Blue Creek Experiment Station. After comparing Wheat-Safflower-Fallow (W-S-F) and W-F rotations for over six years, Dr. Evans discovered that including safflower into the rotation can increase net profits by nearly $200 per acre! The additional profit comes from being able to harvest an additional crop (safflower) during the six year period.
An added bonus to increasing net profits is the reduction of jointed goatgrass in the soil seedbank. After six years, jointed goatgrass density increased more than 5-fold more than the original density in a W-F rotation. Including safflower in the rotation provided an additional disruption to the jointed goatgrass life cycle and resulted in no jointed goatgrass plants emerging after the six year period. Although the lack of emergence does not guarantee jointed goatgrass eradication, the research suggests jointed goatgrass levels in the soil seedbank can be dramatically impacted by extending the crop rotation.
Why Does Safflower Work?
Safflower is a spring planted crop, but jointed goatgrass follows a lifecycle similar to winter wheat (emerges in the fall and matures in the early summer). Selective herbicides like trifluralin (Treflan or other tradenames) can safely be applied to safflower to control weed species, including jointed goatgrass. Some regions have received a Section 18 approval from the EPA to allow the use of specific grass herbicides in safflower (varies by state).
Low rainfall (16-18″ annually) in Utah and Southern Idaho provide conditions difficult to use alternative crops such as corn, sunflower, or similar species. Jointed goatgrass thrives in this environment. Safflower is known to be relatively drought tolerant, and was thought to be effective on reducing jointed goatgrass problems in semi-arid regions where W-F rotations are common. Safflower breaks the jointed goatgrass life cycle through soil disturbance during the spring, herbicide applications shortly thereafter, and possibly post harvest tillage in the fall. All of these activities affect the growth and survival of jointed goatgrass.
Where is Safflower Seed Used?
Nearly all safflower produced in Northern Utah is contracted through Wheatland Seed, Inc. at Brigham City. The raw seed is used in a feed mixture for racing pigeons throughout the United States and possibly other parts of the world. Safflower seed from this region is preferred because it maintains its bright white color, unlike some of the safflower produced in the Midwest.
Safflower is becoming a popular crop to increase net profits with an additional cash crop every six years. Another benefit of this alternative crop is to increase the length of time of a W-F rotation to aid in reducing jointed goatgrass populations. Inserting safflower into the rotation in combination with other management practices is an effective way for wheat producers in Utah to battle jointed goatgrass.