Unless you use no-till or strip-till, tillage is the key to water movement. A variety of vertical-till harrows can be used to level fields after primary tillage, without putting in a dense horizontal layer.
How tillage can establish and maintain a vertical growing system that allows water to work its magic
Tillage helps manage old crop residue and creates a seedbed. We all know that. But did you know the primary purpose of tillage is to manage water?
For successful crop production, water must move up and down through the soil in a vertical format. If you fail to view tillage as a way to enhance water movement, your tillage tool can actually build a barrier to maximum yield. (If you no-till or strip-till, we’re talking about the tillage that occurs before transitioning from conventional tillage or to fix problems afterward.)
Water transports nutrients from the soil into the plant. It is the raw ingredient that makes photosynthesis possible. It constitutes 95% of each plant, and it literally gives plants the strength—called turgor pressure—to stand up. Water works its magic by moving upward from the soil through the plant, where most of it eventually transpires into the atmosphere, starting the entire cycle again.
Tillage is critical to the movement of water because water must be lifted upward through the soil to the plant roots. This lifting action occurs in two ways. One process is adhesion, in which water molecules hook to soil particles. The second is cohesion, which involves one water molecule hooking to another, moving water toward the surface in a wicklike action.
Ultimately, water leaves the field by evaporation from the soil and trans-piration from the plants. If the process hits a snag, water in the soil might be unavailable to plants.
The distance you can lift water varies with soil type. There are various management steps that you can incorporate to help keep water cycling. One of those steps is vertical tillage, which removes compacted layers and creates uniform soil density.
"If roots hit a man-made horizontal layer, they might not be able to penetrate it to reach water," explains Farm Journal Field Agronomist Ken Ferrie.
"In addition, the dense layer causes a barrier to water movement, weakening the adhesion and cohesion processes to the point that water can’t move up fast enough. Once the water near the surface separates from deeper water [creating two water fronts as opposed to one front], your corn plants might wilt, even though there is usable water below the roots."
Farmers understand the benefits of vertical tillage—a term you never heard until a few years ago. Industry has picked up on the concept too, as witnessed by the array of vertical tillage tools now on the market.
"But I see a lot of farmers making mistakes when transitioning from horizontal to vertical tillage," Ferrie says.
The vertical tillage system. "When a farmer tells me he’s switching to vertical tillage, I ask him about his entire tillage program," Ferrie says. "Too many tell me they simply switched to a vertical tillage harrow in the spring. They don’t understand that vertical tillage is a system, not a tool."
It might help to think of it this way: Your goal with vertical tillage is to set up a vertical growing system. That’s true whether you plan to continue doing vertical tillage every year or go all the way to no-till or strip-till.
Problems occur when farmers transition from horizontal to vertical tillage or when they mix and match components without understanding the vertical-tillage system.
- October 2011