Sprayer

A sprayer makes its way across a field. To combat weeds on prevent plant acres, WinField agronomist Kyle Gustafson urges growers to spray weeds early before they are 4 inches or taller.

Heading into what’s likely to be another wet spring, farmers can take some stress out of the planting season by planning ahead.

“Put together multiple plans of action … and take some of that emotion out of the in-season decision making process,” advised Kyle Gustafson, agronomist with WinField United based in Brookings, South Dakota.

That includes evaluating planting dates and deciding when to switch to another crop or consider a prevented planting claim. He expects many of the acres that stayed wet throughout the season in 2019 will likely be prevent plant again. He had advice for managing those acres, as well as fields that will see a crop this year after going unplanted in 2019.

Last spring, some growers tried to plant corn well into June – something Gustafson advises against. Much of the crop planted in June didn’t reach maturity, and it had a low test weight and other issues. He likes to see farmers have a hard and fast date for when they’ll switch to planting soybeans or evaluate the option of prevent plant.

Soybeans can be planted well into the second week of June without changing the maturity, he said. Another option – especially for livestock producers – is growing a forage crop such as sorghum or sorghum-Sudan grass that can be planted late in the season and harvested in multiple cuttings.

The next consideration is weed control. Without a crop to compete with last season, weeds ran wild and created a massive seed bank. Gustafson sticks to the fundamentals of weed control when tackling those problem acres: use an herbicide program with at least three effective modes of action, spray weeds before they’re 4 inches high, and don’t forget to use the correct adjuvants.

“To me, those are the table stakes this year to weed management on prevent plant acres,” he said.

The best bet on common weeds such as mare’s tail, foxtail barley, and kochia is to rely on a burndown herbicide application before planting, then follow up with an in-season residual herbicide for late emerging weeds such as waterhemp, Gustafson said. He added that applicators should use the full rate, not half-rate, and plan to spray more often. If you normally spray two or three times, it might take three or four passes this season.

“I would make sure I stay on offense this year to try to control those weeds,” Gustafson said.

If a field won’t be planted and will go into prevent plant for a second growing season, managing weeds is still important. Gustafson stresses not to let weeds get too tall. Herbicides are designed to work on plants 4 inches or less, but last year he saw growers spraying monster weeds, 5 feet tall.

“That’s asking a lot out of an herbicide to do the job,” he said. “We have to get the timing a lot better this year.”

Cover crops can be a good tool to choking out noxious weeds, but growers should be careful when buying seed. Mixes that come from southern states such as Kansas and Texas, where weeds like Palmer amaranth are prevalent, have the potential of introducing weeds to new areas. Gustafson expects Midwest growers may find Palmer amaranth in new places this year as a result of such a problem.

“That’s the last thing we need,” he said, advising growers to take the time to research where their cover crop seed was grown.

Once a cash crop is in the ground, getting the right nutrients it needs to grow is the next concern. Phosphorus and potassium don’t change much when a crop isn’t harvested, but on prevent plant acres, fallow syndrome that was an issue in days of old can become a problem. Without a host plant, the fungi in the soil that helps crops use phosphorus can die off, Gustafson explained. On 2019 prevent plant acres, he suggests using a starter fertilizer with phosphorus and maybe some zinc.

Providing enough nutrients throughout the growing season is another consideration. It’s a good year to split applications of fertilizer because wet soils are more prone to leaching and denitrification.

Gustafson suggests putting on half to 70% of your nitrogen and sulfur before planting and adding the other 30-50% when the corn is at the V5 to V6 growth stage in mid-June – either by side or top-dressing. Soil and tissue sampling can help determine the crop’s needs.

“I’d take some in-season measurements and let that guide your decision on in-season nutrients,” Gustafson said.

Another late start to the planting season could shift more acres to soybeans. Growers can plan ahead to protect their beans from problems caused by wet conditions, such as root rot. Gustafson saw that seed treatments made a difference last year. They can help a soybean stand combat disease pressure.

“A good, quality seed treatment is a must,” Gustafson said. It’s all part of making the most of what’s looking to be another wet year.

Janelle is editor of the Tri-State Neighbor, covering South Dakota, southwestern Minnesota, northwestern Iowa and northeastern Nebraska. Reach her at jatyeo@tristateneighbor.com or follow on Twitter @JLNeighbor