Hundreds of acres of sunflowers, bright golden faces beaming, are a sight to make one feel exhilarated on a summer day.
Last year in Yolo County, nearly 25,000 acres of sunflowers were planted. That could be a lot of bird seed. But 95 percent of the sunflower seeds grown in Yolo County are sent around the world to be planted for oil. They end up as far away as Russia, Ukraine and Argentina.
According to Glenn Cole, research scientist for Pioneer Hi-Bred International in Woodland, the United States grows sunflower for oil on only about 2 million acres, largely in the Dakotas. Russia and the Ukraine each have 20 million cultivated acres of sunflowers.
Helianthus annuus is native to North America and was cultivated in what is today Arizona and New Mexico by Native Americans about 3000 B.C., perhaps before corn was domesticated. Spanish explorers took the plant back to Europe where it became popular as an ornamental plant but also was used for oil production.
The Russian Orthodox Church ensured its popularity by forbidding the consumption of animal fat during Lent, so sunflower oil was a natural substitute. Little was known at that time of its high nutritional value.
When you look around Yolo County at expanses of mature sunflowers standing straight and tall, you notice three things:
* One is that the large single flowers all face east. All day long. Given that the name of sunflower in Spanish is girasol and in French, tournesol, meaning “turning with the sun,” that is surprising.
The explanation is more complicated. The flower buds do move with the sun before they open, an activity known as heliotropism. It is driven by changes in fluid inside the stalk at the base of the bud during daylight as the stalk grows. As the plant matures, the stalk stiffens and the flower begins to open and no longer moves.
* The second thing one might notice is that there are six to eight to 10 rows of sunflowers of uniform height and two rows of sunflowers that may be taller or shorter. The two rows are males needed to pollinate the female flowers. Unlike the single-headed females, the male plants have branched stems and carry several smaller flower heads to maximize pollen production and male bloom period.
To illustrate, near the S-curve on Russell Boulevard between Davis and Winters, a large field was planted this summer with multiple rows of very short female flowers, only a foot or so high. The double rows of male plants were roughly twice the height of the females.
“There are many different varieties of sunflower that have been developed by the seed companies,” Cole explained. “There could be almost any variation in height or other characteristic between the male and female flowers. The one sure fact is that you need them both to make a viable hybrid first-generation seed to plant for oil production.”
* The third thing that becomes apparent later in the season is that male plants suddenly disappear from the field. A double row of barren ground appears between the multiple lines of female flowers. Males are removed early before the female seed-bearing plants are allowed to dry out and harvest begins. This eliminates contamination of the female-produced first-generation hybrid seed (F1 hybrid seed) that is used for oil production.
According to literature of the National Sunflower Association, sunflower is not a genetically modified plant. Two factors make this not an option. One is that Europe is a large market and the European Union will not accept GMO seed. Secondly, because wild sunflower is a native and widely dispersed plant in the United States, it would be virtually impossible to grow GMO seed and prevent gene flow to the native species.
Managing the logistics of which grower is going to plant which variety, in what field and when is something of an organizational nightmare. There are several seed companies and many growers, so allocating varieties to distinct fields becomes a difficult task.
In any given year, a seed company is not only growing the F1 hybrid seed for export but also must be growing the parent seeds, both male and female, to use for next year’s plantings, Cole said.
“Sorting this out starts by the growers telling the seed companies what fields are available,” said grower Tony Turkovich. “A field cannot have had sunflowers planted in it in the past couple of years, in order to reduce the probability of unwanted seeds growing.”
Added grower Rick Rominger, “In roughly January, the seed companies get together with a big map, and ‘pin the fields.’ It’s like a horse-trading marathon. They solve the puzzle of how to isolate the fields in space and time. And, if a grower has had to plant second the year before, he gets a first planting this time.”
“It’s a matter of being courteous,” added Turkovich.
After the female flower heads have developed seeds and the male plants have been removed, water is withdrawn from the fields and the female seed heads are allowed to dry. The harvester used for sunflowers has a front end as wide as the multiple rows of female flowers and cutting blades like Edward Scissorhands fingers that move down the rows, decapitating the heads.
The seeds drop out and are conveyed by a chute into the bed of a waiting truck like a flow of black oil.
Each lot of seeds is tested for percentage germination, weed seed, inert matter and varietal purity. During the growing season, the fields are inspected one time before bloom and twice while in bloom to certify that there are no “rogue” plants growing or other crop and disease contamination that may negatively affect seed quality, according to Timothy Blank, a seed certification specialist with the California Crop Improvement Association.
In 2013, the sunflower seed crop in Yolo County was worth $1,143 per acre on average, gross, according to the 2013 Agricultural Crop Report.
Sunflowers are a nutritious snack. They have higher levels of folate (vitamin B9), vitamin E and selenium than almonds, walnuts, pecans and hazelnuts, according to the National Sunflower Association. Their website, www.sunflowernsa.com, has a wealth of information about sunflowers.