Fertilization and protection may increase health and yields in sunflower cropsWritten by Natasha Wheeler
South Dakota farmers Brian and Darren Hefty believe that properly feeding a sunflower crop, as well as protecting it from weeds, insects and diseases, will improve yields dramatically.
“Much like soybeans, sunflowers are very misunderstood when it comes to fertility,” remarks Darren.
Comparing two farms nearly 100 miles apart, he acknowledges the differences in growing conditions yet remarks on the significant crop improvements in a fertilized field.
“The first farm had a very specific fertility program for sunflowers. The stalks were big and mostly disease free. They stood very well until harvest and had big heads on the sunflowers,” Darren describes.
In the second field, the farmer’s philosophy is that sunflowers are a scavenger crop, and his plants had thinner stalks, lower quality stands and more disease.
“When we looked at a plant tissue analysis, we saw a lot of deficiencies. It was amazing to me what a difference there was in fertility from one farm to the next and what a difference that made in production,” he states.
The field with a special fertility program yielded nearly twice the crop as the unfertilized field.
Brian notes that there are three key nutrients to think about when growing sunflowers.
“If we’ve had lodging problems in any crop, it’s probably a potassium issue. It could also be manganese or copper. Those nutrients are all important if we’re looking at sunflowers,” he says.
Protecting the crop
Various diseases may also occur in sunflower crops, and Darren notes that many successful farmers use fungicides, with at least one application, if not two, per year.
“We’re protecting against white mold, powdery mildew and other diseases that can be very problematic in sunflowers,” he explains.
Insects can also pose a threat to sunflower crops, and there are a number of critical stages where bug pressure can become a problem, according to Darren.
“It’s important that we are out scouting on a timely basis. The best sunflower producers in the country are out at least weekly, looking in their fields with sweep nets, identifying which bugs are out there and spraying with appropriate products,” he states.
Brian adds, “The good news is, the appropriate products are very inexpensive. If we have a seed that’s protected from bugs and we spray foliar once or twice for bugs, we’re generally in pretty good shape, and we haven’t even invested $10 an acre.”
When it comes to preventing weeds, Brian and Darren highly recommend using pre-emergence strategies.
“We have two options. We have yellow, and we have PPO. We want to make sure we are using them both,” Brian remarks. “The problem is, sunflowers don’t give us very good crop canopy later on, and we don’t have any good foliar options for weeds.”
The combination of herbicides helps to deter small-seeded broadleaves that cause weed problems in sunflower crops, and they can be followed with a post-emergence grass killer later in the season.
“It’s fairly inexpensive if we need rescue options for grass, but we don’t have any good rescue options for broadleaves,” he says.
Brian also suggests giving management changes a few years to yield results as the potential benefits for the crop increase after a few seasons of providing protection and fertilization.
“There are many things we can do if we want to improve tonnage on our farms,” he remarks.