While some areas of Missouri saw high water and flooding this year, parts of Iowa and northern Illinois experienced dry conditions during the growing season.
Agronomists and ag engineers say growers should evaluate each situation when making fall tillage decisions.
Kent Shannon, University of Missouri Extension ag engineering specialist, says for fields that had water on them, the first step is getting them clear of any debris that washed up, then determining how deep to till.
“Figure depth of tillage,” Shannon says. “If there was some minor sand deposits, you may want to think about tilling it a little bit deeper.”
Joel DeJong, an Iowa State University Extension agronomist based in northwest Iowa, says soil type is also a factor to consider. It was a dry year in his area, which he says could grant a good opportunity to take care of any compaction zones, although the area has received some fall rains now.
“I’m in a part of the state where we have a lot of loess soils, wind-blown soils,” DeJong says. “If there’s a soil type that needs less tillage, it’s these loess soils.”
Gentry Sorenson, an Iowa State University Extension agronomist based in Algona, covering parts of north central and northwest Iowa, says his area has more clay soils. He says farmers sometimes opt for fall tillage for a few reasons.
“Getting the residue worked in, breaking up the hardpan if they can,” he says.
Sorenson says the tillage helps the soil warm up quicker and be ready for spring field work sooner. He says many farmers in his area use a chisel plow or strip tilling. Some of them have looked to cover crops to help prevent offseason erosion, especially after tillage.
“There are a lot of guys that ask questions about cover crops,” Sorenson says.
In general, Shannon says the rise of no-till practices have led to tillage being a more targeted approach.
“Tillage is more of a minimal-type operation,” he says.
DeJong says fall tillage should only be done when necessary, not out of habit.
“Don’t do fall tillage if you don’t have to,” he says. “… Make sure there’s a reason other than just tradition.”
DeJong says one important reason to till is if farmers have compaction zones, which can limit root development. He says in the loess soil they have measured roots over 9 feet deep, and the difference between roots that are 5 feet deep and 2 feet deep can be huge, in terms of how much water they can get from the soil and how much rain they need.
“Do we have roots that are able to utilize the water-holding capacity of soil?” he says.
DeJong says to only till to the depth of compaction.
“I don’t encourage going any deeper than you have to,” he says.
Sorenson says with the dry conditions in his area this year, there probably won’t be a lot of compaction issues.
But for farmers who had to harvest in slightly wetter conditions, they may need deeper tillage implements for fixing ruts.
“A vertical tillage tool is probably not going to be able to deal with good-sized ruts,” Shannon says. “Then you’re going to need a deeper-type tillage tool.”