It won't be long until farmers are in the fields. Going into the spring season there is some talk about dry weather possibly occurring in the summer of 2011, based on indications of the La Nina weather pattern. "We have plenty of subsoil moisture in our area of northwest Iowa and in the rest of the state," observes Paul Kassel, Iowa State University Extension agronomist at Spencer. "A drier- than-normal spring would be welcome to get corn planted on time. But we need normal rainfall the rest of the growing season. With corn supplies low this year and demand continuing strong, the market is telling us we don't need a drought.
"There are things farmers need to be thinking about before it comes time to head to the field," says Kassel. He outlined several considerations and answered questions at an ISU Extension crop meeting at Pocahontas in northwest Iowa recently.
One question he's received often from farmers this winter is "How can I control Sudden Death Syndrome in soybeans?" SDS is a devastating disease that hit some areas of Iowa hard in 2010. "SDS isn't a totally new disease here in northwest Iowa," notes Kassel. "But it is somewhat new. Many bean fields had a little bit of SDS infection here and there last summer in northwest Iowa. SDS wasn't as bad here as it was in central Iowa and southeast Iowa—the two areas of the state where it seemed to be most widespread."
Last spring's weather was 'perfect storm' to set up SDS infection
Have ISU agronomists been able to narrow down what is causing SDS? "I've heard farmers speculate that it's weather, everything from too dry to too wet," he says. "I've also heard some farmers speculate that SDS has shown up more in recent years because of the widespread use of glyphosate herbicide. But that hasn't been proven."
Most of the soybeans were planted in Iowa by the end of the first week of May, this past spring. "Then we had rainy, cold weather and frosted corn on Mother's Day," recalls Kassel. "So that was part of the reason why we had problems with SDS last summer. The infection happens early and then with all the rain we had through the summer, it caused more SDS occurrence and damage to beans."
Can farmers find a variety of soybeans has more resistance to SDS? One thing you may want to consider is the connection between SDS and SCN. "Soybean cyst nematode resistance is bred into a lot of soybean varieties now," answers Kassel. "The availability of nematode resistance in soybean varieties is something farmers and agronomists are well aware of and there is a connection between SDS and SCN. In fields where there is more SCN, there's usually more SDS infection. Soybean cyst nematode problems aren't as severe as they used to be, as more farmers are planting SCN-resistant beans today."
Planting bean varieties that have SCN resistance helps control SDS
Planting bean varieties that have SCN resistance won't get rid of SDS, but it will help you manage the SDS problem somewhat, says Kassel. And of course, SDS resistance is something you should look for in selecting soybean varieties to plant. "Planting varieties that show SDS resistance is something you should do," he adds. "Look for the good yielding varieties that have some SDS resistance."
You also have to realize that weather has a lot to do with how serious a disease infection will be in a field. Last year's cold, wet spring and wet growing season favored the development of SDS.
Corn or beans in 2011? More corn will be planted in Iowa this spring
Farmers have seen a big rise in corn and soybean prices since last spring. Will more corn or more soybeans be planted this spring? "My view is there will be more corn acres planted," says Kassel. "We've had a trend that way even before ethanol got going as a huge user of corn. Farmers are still frustrated with growing soybeans. The yields haven't increased for soybeans like corn yields have, and beans have problems such as soybean cyst nematode and disease problems."
The yield level for soybeans hasn't keep up with the increase in corn yields, he adds. "Farmers are concerned about that, and from what I gather from farmers I talk to here in northwest Iowa, I think there will be more of an increase in corn acres planted this spring than in soybean acres."
Also, farmers and agronomists have kind of figured out the corn-on-corn rotation, notes Kassel. Many farmers have chopping cornheads on combines now to help them handle the crop residue, beginning at harvest. And they are using better tillage implements to help manage the extra crop residue you get with corn on corn. Many farmers have been quite successful with corn on corn.
More farmers figuring out how to grow corn on corn successfully
Is there a yield penalty with corn on corn? "Yes, I think there probably still is a yield penalty, but it's been minimized somewhat," says Kassel. "Farmers have the harvesting and tillage equipment now that's better at chewing up the corn residue and burying some of it, but still leaving some on top for erosion protection. Planters are better, too, at slicing through the crop residue and kicking some of it out of the way so you can get proper placement of seed in the soil.
"We're seeing less of a yield penalty with corn on corn," he notes. "But we still have some fields here and there that will yield 20 or 30 bushels less per acre than a neighboring field of corn following soybeans. But there is less of that now. So, people have been able to figure out better ways to manage corn on corn to make it quite successful."