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Vertical Tillage Should Move Little Soil
One of the most recent trends in tillage equipment is vertical tillage. There are several manufacturers of vertical tillage equipment, and none of the implements is exactly the same. But there are some common features.
"From a distance, many vertical tillage tools look very similar to discs in that there are a series of round blades in a gang on a toolbar," says DeAnn Presley, soil management specialist for Kansas State University. "However, some models have blades individually mounted on springs, similar to a field cultivator."
"Offset discs are primarily used as primary tillage tools and tandem discs are usually used as a finishing tool. In contrast, most vertical-tillage implements are being used as a one-pass operation directly on crop residues prior to planting."
One of the physical differences between the two types of implements is that tandem disc blades are more curved, go a little deeper into the soil profile and turn up some soil as they go across the field, Presley says.
Vertical tillage blades are generally straighter, more like coulters, and are often fluted. In fact, many manufacturers refer to the blades on vertical-tillage implements as coulters. The degree of curvature and amount of fluting on the coulters varies by manufacturer, as does the angle of the gangs.
"The blades on vertical-tillage implements typically go only about 2 to 3 inches into the soil, and do not move much soil as the implement goes across the field," Presley says. "Vertical-tillage implements will have a slight to moderate smoothing effect, which is usually enhanced with smoothing bars, harrow tines or rolling baskets behind the discs."
Tandem discs create more draft and have a somewhat higher power requirement than vertical-tillage equipment. Producers using a vertical-tillage implement can usually go faster across the field, up to 6 to 7 mph, than when using a tandem disc, Presley adds.
"Vertical-tillage equipment is used to lightly till the soil and cut up residue, mixing and anchoring a portion of the residue into the upper few inches of soil while still leaving large quantities of residue on the soil surface," she says. "This action helps speed up residue decomposition."
Presley says the best description for vertical tillage is to call it a form of mulch-till, as it generally leaves greater than 30% residue on the soil surface, yet creates nearly full-width disturbance on the soil surface.
"The main objective of using vertical tillage is to break up surface soil compaction or smooth out areas in a field with shallow rills from water erosion or ruts and tire tracks from tractors, combines, grain carts, trucks and other equipment," Presley says. "It's also used to help improve rainfall penetration by breaking up crusts.
"However, if a hard rainfall occurs after the vertical-tillage operation on a low-residue environment, it could have the opposite effect. Vertical tillage should only be used when the soil is dry enough to shatter; otherwise, it may create shallow compaction."
This type of equipment tends to leave the soil somewhat fluffy, but not quite to the extent that a tandem disc will.
Presley says Kansas State has begun to evaluate the effect of vertical tillage on corn stalks and subsequent soybean yield, soil bulk density, soil aggregate stability and water infiltration on various soil types in northeast Kansas.