Journal of the NACAA
Volume 5, Issue 2 - December, 2012
Dryland Safflower Response to Dormant Seeding in Utah
- Pace, M.G., Agriculture/Horticulture Agent, Utah State University
Creech, E., Extension Agronomist, Utah State University
Israelsen, C., Agriculture Agent, Utah State University
Spring seeded safflower has been successfully grown as an oilseed crop on dryfarms in Northern Utah and Southern Idaho for many years. Over the past several years, winter hardy safflower varieties have been developed that permit safflower to be sown in the fall much like a winter wheat crop. Dormant seeding of spring safflower varieties on dryfarms showed great potential in this trial with the highest yields reaching 2,343 lb/acre. This research showed an increase of 1,190 lb/acre between the dormant and spring seeded variety S-719 with an estimated increase in gross profits of $261 per acre.
Safflower (Carthamus tinctorius L.) is an annual oilseed crop grown in Utah primarily for the birdseed market. The crop has been grown in experimental test plots in the United States since 1928 (Berglund, Riverland, & Bergman, 2007) and on a commercial basis in Utah since 1957 by area farmers for Pacific Vegetable Oils (PVO)(Smith, 1996). Safflower is well-adapted to the high desert climate and has been grown successfully in areas receiving 10 to 20 inches of annual precipitation. As a result, safflower is considered the most heat and drought tolerant of the alternative agronomic crops commercially available (Kephart, Murray, & Auld, 1990). It is especially popular on Utah dryland farms in rotation with winter wheat because of its ability to extract deep moisture from the soil profile with its long taproot. On dryfarms, the ground is fallowed the year after growing safflower in order to recharge the soil moisture profile for winter wheat production the following year. Recently, winter hardy safflower variety lines have been developed which permit safflower seed to be sown in the fall much like winter wheat. Yields of fall sown safflower in Northeastern Oregon were as high as 1,900 lb/acre (Petrie et al., 2010).
Most safflower seed in Northern Utah and Southern Idaho is sold for the birdseed market. Utah State University Cooperative Extension researchers have conducted several irrigated and dryland varietal performance research trials on new safflower varieties. Their purpose is to assist growers in selecting new safflower varieties that perform well under Utah growing conditions. In Northern Utah, growers usually have fall rains which germinate the winter crops followed by snow cover from December through the end of March. Spring rains in April and May give spring and fall planted crops some much needed surface moisture followed by dry summer months. This type of seasonal weather pattern makes it extremely important for growers to have their dryland crops seeded as early as possible to take advantage of timely spring rain storms.
Dryland safflower yields in Utah can be severely limited by soil moisture. Higher yields always occur in years with plenty of winter and spring moisture versus dry years. Earlier planting dates may allow safflower to more effectively utilize Utah’s winter/early spring precipitation pattern. New fall or winter safflower varieties could possibly allow growers to plant in the fall (much like winter wheat), where safflower would emerge in the fall, over-winter as a small rosette, and resume growth early in the spring.
The objective of this research was to compare the performance of fall versus spring seeded safflower under Utah dryland conditions.
Materials and Methods
Experiments were conducted at the Blue Creek Research Farm located in Box Elder County, UT (GPS 41o56’08.94” N 112o26’18.62” W) on a Timpanogos Silt Loam soil over two growing seasons; 2009-2010 and 2010-2011. Soil samples were analyzed for nitrogen (N), phosphorus (P), and potassium (K) and other essential elements for proper safflower growth. Only N was identified as being low and was applied in the spring of both years based on soil test results and recommendations. N was applied at 40 and 50 lb/acre in spring 2010 and 2011, respectively.
The seedbed was prepared as if it were to be planted with winter wheat during the fall. No pre- or post-plant herbicides were applied to the plots and weeds were controlled by hand rogueing the plots the following spring and summer. The fall plots were planted on December 1, 2009 with 3 winter safflower varieties (PI 651878, PI 651879 & PI 651880) and one spring safflower variety (S-208). S-208 is the field standard in Northern Utah and Southern Idaho. The original intent was to seed the varieties in the fall (September - October) when there was sufficient moisture to germinate the safflower. The fall and winter of 2009 was very dry with insufficient moisture to germinate the safflower crop. The decision was made to plant the plots in December as a dormant planting and hope the safflower seeds would germinate in the spring when the soil temperatures became sufficiently warm. The plots were planted using a small-plot cone seeder (Figure 1) at 12 lb/acre using a12-inch row spacing. Individual plots measured 4 feet wide by 30 feet long with four replications in a Randomized Complete Block split-plot design.
Figure 1. Planting safflower plots with a small-plot cone seeder.
No germination occurred on any of the safflower varieties until early spring of 2010. This earlier than normal planting and spring germination allowed the plants to utilize the spring rains for seed germination and growth. Moisture was not lost in the dormant seeded plots due to soil preparation in the spring. Soil preparation for the spring planted S-208 variety was completed as early as possible, on May 4, 2010 as a comparison for the dormant seeded plots. The plots received approximately 2 inches of rain during the spring and early summer. The late summer months were hot and dry. The dormant seeded safflower plants flowered in late June (Figure 2) and were ready to harvest in late August. The spring seeded plots flowered in the middle of July and were ready to harvest in late September.
Figure 2. Dormant seeded safflower in bloom on the left and right sides of spring planted safflower in the center.
The plots were harvested with a small research plot combine on September 29, 2010. (The researchers note that the dormant seeded plots could have been harvested in late August, but because we had other research plots to harvest in September as well, we elected to harvest all plots together at the later date). A sub sample of each plot was bagged and labeled with the plot number and sent to a private safflower buyer for color scoring. The color score is a visual rating from 1 to 10 (1=whitest and 10 being a tan/brown color). The percent oil content shown in the table is the amount of oil relative to the total seed weight. The percent oil content is determined by measuring seed that has been cleaned and is at 0% moisture after drying at 105oC for 24 hours in a forced-air drying oven. This information was completed by a private lab with equipment for testing oil content and was a composite sample from each variety. The gross income was figured on the seed production at 14 cents per pound. Seed prices were based on contract prices offered to local growers in the spring of the growing season unless otherwise noted. Crop inputs (fertilizer, pesticides and equipment costs), color score and oil content were not figured into the gross income per acre figure. The safflower yields were analyzed by ANOVA (NCSS 8.0.13 version) with yield means separated with Fisher’s protected LSD (P ≤ 0.05).
Results and Discussion
The safflower yield results (Table 1) show S-208 as a dormant planting out yielded the fall seeded varieties with 960 lb/acre compared to winter varieties PI 651879 at 811, PI 651878 at 793 and PI 651880 at 771 lb/acre respectively. Planted in the spring, S-208 yielded 832 lb/acre. The yield reduction of 128 lb/acre by planting in the spring vs. fall equates to $17.92 per acre just by changing the planting date of the safflower variety. Oil seed content in Utah spring seeded safflower usually ranges from 35 to 42%. The oil content for S-208 variety (fall or spring planted) was in line with these oil levels, whereas the winter safflower varieties were well below the average at 25.8 to 26.2%. The total amount of oil per acre was determined by seed production yield and the percent oil concentration. Because of the low percent oil content and the low yields for the winter safflower varieties, the pounds of oil produced are reflective of both these low numbers. If one was growing safflower for an oil market, we caution growers on the use of winter safflower varieties based on our experience.
Table 1. 2009-2010 Dryland safflower results for dormant versus spring planted safflower, Blue Creek, Utah (Box Elder Co.).
|% Oil Content
|Lbs. of Oil
|S-208 - Dormant Seeded
|S-208 - Spring Seeded
*Winter Safflower Variety
zYield means were not significantly different (P=0.34)
After observing this type of a yield increase in safflower by seeding it early as a dormant planting to take advantage early spring moisture, the researchers were interested to see what would happen in the second year of the study. The plots were prepared as they had been the previous year and winter came earlier than expected. We were unable to plant the safflower in late November or early December due to large snow fall amounts and freezing temperatures that made it impossible to insert the seed openers into the ground. On April 7,2011, we were able to seed a replicate trial of last year’s plot with the addition of two other spring safflower varieties. After seeding the plots the area received several additional snow and rain storms that kept the safflower dormant until the first part of May when the seeds germinated. In this planting, we had winter and spring seeded safflower which were seeded as a dormant seeding and also had spring seeded safflower varieties which were seeded as a true spring seeding. 2011 was an unusually wet spring for Northern Utah and delayed the planting of many spring crops in the area, with safflower being one of them. Spring planted safflower in this plot was not planted until June 1, 2011, about 2-3 weeks later than a normal spring planting due to above average rainfall. There was no winter safflower varieties seeded in the spring seeding. The results of the 2010-2011 dormant versus spring seeding of safflower is found in Table 2 below.
Dormant-seeded spring saffloweraveraged 2,009 lb/acre whereas the winter varieties averaged 1,308 lb/acre. The highest yielding dormant spring safflower variety was S-719 at 2,343 lb/acre with Hybrid 9049 being significantly lower at 1,631 lb/acre. In contrast, the highest yielding winter safflower variety was PI 651879 at 1,381 lb/acre, followed by PI 651878 at 1,308 lb and PI 651880 at 1,235 lb/acre respectively. The difference between the lowest producing spring variety and the highest producing winter variety was 250 lb/acre. The top yielding variety, S-719 produced 2,343 lbs as a dormant seeding, yet only 1,153 when planted in the spring. With all other inputs the same, the earlier planting date resulted in an increase of $261 per acre in gross income.
Table 2. 2010-2011 Dryland safflower results for dormant versus spring planted safflower, Blue Creek, Utah (Box Elder Co.).
|Seeding Date in 2011
|Yield Difference Between Planting Dates
|Gross Income per Acre*
|Seed Production, lb/Acre z
* Gross income is figured on seed production at 22 cents per lb.
** Winter Safflower Variety
zYield means followed by the same letter are not significantly different according to Fisher’s protected LSD (P ≤ 0.05).
One area of study which needs to be followed up on is the lack of hard frosts either year after the spring seeded safflower started to grow. Safflower tolerates temperatures as low as 20oF while in the rosette stage (Berglund et al., 2007). These types of low temperatures were not experienced either year of the study and producers could find this to be a problem. Because most herbicides are applied pre-plant and incorporated into the soil before planting safflower, we experienced weed problems with annual broadleaf weeds like prickly lettuce, Russian thistle and kochia. The application of herbicide impregnated on fertilizer or finding a broadleaf herbicide that can be applied post emergent on safflower will be important if growers are to have success growing safflower from a dormant seeding.
Summary and Conclusions
The dormant seeding of spring safflower varieties on dryfarms has shown great potential in Northern Utah and Southern Idaho, with the highest yields reaching 2,343 lb/acre. Second year research indicated a significant difference of 1,190 lbs between the dormant and spring seeded variety S-719, with an estimated increase in gross income of $261 per acre. The research also demonstrated that S-208 in the dormant seeded spring safflower varieties had significantly higher yields than dormant seeded winter varieties in both years. Winter safflower varieties, when seeded as a dormant planting, had significant lower percent oil content when compared to traditional spring safflower varieties.
Berglund, D. R., Riveland, N., & Bergman, J. (2007). Safflower Production. North Dakota State University Agricultural Extension Bulletin A-870. http://www.ag.ndsu.edu/pubs/plantsci/crops/a870w.htm
Kephart, K. D., Murray, G. A. & Auld, D. L. (1990). Alternative crops for dryland production systems in Northern Idaho. p. 62-67. In: J. Janick and F.E. Simons (eds.), Advances in new crops. Timber Press, Portland, OR.
Petrie, S., Machado, D., Johnson, R., Prichett, L., Rhinhart, K., & Tuck, B. (2010). Adaptation and Yield of Spring and Fall Sown Safflower in Northeastern Oregon. Columbia Basin Agricultural Research Center Dryland Research Report 101. Oregon State University. http://cbarc.aes.oregonstate.edu/sites/default/files/adaptation_and_yield_of_spring_and_fall_sown_safflower_in_northeastern_oregon.pdf
Smith, J. R. (1996). Safflower. p 77. The American Oil Chemists Society (AOCS). The Development of the PVO Strategy. By AOCS Press http://www.crcnetbase.com/doi/abs/10.1201/9781439832080.ch4