A good year to dodge fall tillage?
It's fall. You're busy with not just harvest, but likely starting to plan ahead for next year's crop. One of those preparations may be better left until spring, one expert says.
Despite recent rainfall around the Corn Belt, it's been bone-dry in a lot of the region leading up to harvest. That means the soil's going to need all the help it can get in getting fully recharged with moisture between now and next spring. Under the current circumstances, keeping the disc out of the field until then, says Iowa State University Extension agronomist Mahdi Al-Kaisi, is a good idea.
"Pay attention to tillage intensity after harvest; tillage affects soil conditions and destroys soil structure, which can create significant problems. Tillage accelerates organic matter loss, which results in more problems of accelerating soil erosion and surface runoff," Al-Kaisi says. "Those changes in soil condition with tillage during rain events after harvest can also reduce soil profile recharge due to increased surface runoff.
"Leaving crop residue on the soil surface has many benefits not only in minimizing future negative effects of soil erosion and sediment and nutrient losses, but also works as an effective method of trapping soil moisture, which later easily penetrates into the soil and recharges the soil profile. Tillage of any kind damages the soil by reducing the residue cover and its effect in protecting the soil surface," he adds.
This may sound counterintuitive; Al-Kaisi says a common misconception lies in the notion that integrating crop residue improves overall soil organic matter. Though it does function in this way, tilling it up can also break up soil structures to the point that the benefits to organic matter are outweighed by the drawbacks to soil structures.
"A common misconception is that shredding or incorporating residue with tillage will enhance soil organic matter or improve other physical and biological properties, which are essential to a well-functioning soil," Al-Kaisi says. "However, research documents that crop residue can be most effective when left intact on the soil surface protecting soil quality, such as soil structure, water infiltration, soil moisture holding capacity, and soil bulk density to name few. During dry conditions, removing residue or incorporating it can affect those soil qualities, especially at the soil surface, causing surface sealing during rain events and subsequent soil crusting."
Al-Kaisi recommends these tips to better manage soils this fall if you're facing potential issues with compaction and resulting adverse effects on the land between now and next spring:
Avoid "unncessary" tillage. "Conventional tillage to incorporate residue, such as deep ripping, chisel plow and even vertical tillage, etc., can have negative effects, especially after persistent drought conditions when soil structure is weakened," he says.