By Padma Nagappan
The majority of California’s sunflower crop is grown in the Sacramento Valley, mostly for seed production.
The state accounts for 95 percent of the U.S supply and 25 percent of the world’s supply of sunflower seeds.
Planted acreage tends to vary greatly year-to-year, because most of it is used as planting seed for farmers that grow it for cooking oil, so the commodity markets dictate demand. Sunflower acreage was at 45,000 acres in 2016 and went up to 54,000 acres in 2017, according to the U.S Department of Agriculture’s estimate in 2018.
Khaled Bali is a University of California Department of Agriculture and Natural Resources statewide water and irrigation specialist who has been working since 2016 on a four-year trial on sunflower varieties.
He was asked by the University of Georgia to help ascertain which varieties were drought resistant. He chose to conduct his trial in the low desert region of the Imperial Valley, since it gets little rain during the growing season between February when it’s planted, and June when it’s harvested. This would make it easier to control and measure the actual water applied to the crop varieties.
“We’re looking at 285 varieties of sunflowers, to see which ones do well under stress,” Bali said. He has tested different plantings each growing season for the past three years, and will finish the trial this year.
Although he had not worked with sunflowers before, he found it was an easy crop to grow. The season can range from 120 to 140 days, but if the crop is planted later in the season, it cuts short the growing period.
He used subsurface drip irrigation to test the crops at different water levels, ranging from 60 to 100 percent. Bali explained that drip works better than furrow irrigation, since it offers better control and precision.
At the end of Year One, they found little difference between the stressed plants and the ones that got ample water, so they switched gears for Year Two. His team tested the stress group with 10 percent of water requirements, supplementing with 50 percent additional water from ground water sources.
For this current last round of trials, they will select the varieties that did well under stress conditions and plant them again, but spread out the planting timeframe from February through March, to see the impact this has on yield.
He will have conclusive findings at the end of the growing season this year. Some varieties yielded 100 grams of seed while others gave 300 grams.
This is a relatively new crop for the low desert region in California, with about 1,700 acres planted, half for seed production and half for cut flowers. But Bali said it’s a good crop given it has low water use.