By MIKE MILLER
OSU Extension Medina County

Farmers may practice tillage to break up compacted soil, aid in seed germination and control weeds, but how the soil is tilled has the most impact on crop productivity.

Although agronomists encourage the use of no-till for the agricultural and environmental benefits it affords, there are some instances where farmers may want to use tillage. In those cases, vertical tillage is usually more beneficial than horizontal tillage, said Randall Reeder, an Ohio State University Extension agricultural engineer.

“Helping farmers understand that there are differences between tillage practices helps them choose the proper tools to get the most out of crop productivity, maximizing yields as well as their profits,” said Reeder, who also holds an Ohio Agricultural Research and Development Center appointment.

With horizontal tillage, usually about 4 to 8 inches of topsoil is sheared off, broken up and laid over a previously cut surface. If the soil is moist, the process smears the soil between the tilled and the untilled layers.

“If you scraped away the tilled layer of soil what you would see is a smeared soil surface, like if you had smoothed out the soil with a butter knife,” said Reeder. “That smeared surface often creates a physical barrier that impairs root growth and water and air movement and has a major impact on the soil and crop performance.”

Moldboard plows and field cultivators are examples of horizontal tillage tools. Reeder said the long-term result of using a moldboard plow is the development of a plow pan, a compacted layer of soil that generally is too hard for roots to penetrate. Vertical tillage includes a wide range of equipment, Reeder said.

Subsoilers and chisel plows, for example, are designed to create vertical zones by cutting slots about 6 to 16 inches deep, shattering the soil between the tillage shanks at natural break points and lifting the soil to loosen it.

Strip-till units create narrow tilled strips 30 inches apart, where the next corn crop will be planted, and do not disturb the soil between.

Other vertical tillage tools, such as straight or slightly angled coulters, penetrate only an inch or two, mainly mixing a little soil with the crop residue. Tools with “rolling spikes” can punch holes 2 to 8 inches deep, improving water infiltration and soil aeration.

Reeder said vertical tillage is a much more attractive option than horizontal tillage due to a number of benefits, including improved root growth, reduced soil erosion by leaving more crop residue on the soil surface, and energy savings.

“I prefer continuous no-till. But if a grower wants to till, vertical tillage is the next best choice,” Reeder said. “Vertical tillage tools that leave most of the crop residue on the surface can maintain or increase yield while at the same time providing environmental benefits and reducing costs.”

Miller is the agriculture and natural resources agent of Ohio State University Extension, Medina County. For more information, call Ohio State University Extension Medina County at 330-725-4911, 330-336-6657 or 330-225-7100, ext. 9237. Visit the Extension’s Web page at www.ag.ohio-state.edu/~medi.