Timing and intensity of tillage can have dramatic, long-term effects on soil health. Mechanical disturbance of the soil can destroy the soil's natural structure, close macro pores, and pave the way for compaction and erosion. In addition, excessive tillage has been shown to decrease soils' ability to hold water and speed the breakdown of soil organic matter.
This, along with other factors has led to the popularity of no-till cropping. But researchers at Michigan State University underscore the need in some situations for tillage. Crop residue can build up and block nutrients from the soil requiring shallow tillage. Certain crops like potatoes or peanuts require a great deal of soil disturbance, but with corn, beans and wheat, little disturbance is needed on a yearly basis.
According to MSU, "Herbicides, tolerant crop varieties and innovative equipment now make it possible to control weeds and plant a field without upsetting the ground."
However, tillage does not always present the doomsday scenario of compacted, crusty or cloddy soils, low yields and general soil calamity. In fact, tillage is a big part of many Midwestern operations because it works. The initial MSU study was conducted with soybeans in mind, but it is worth a look whether you are growing beans or corn. Michigan State offers the following to help growers think about two major tillage considerations -- timing, and intensity.
- Before tilling, check soil moisture to a few inches below the anticipated tillage depth to make sure the field is sufficiently dry.
- It is hard to be patient, but tilling too early increases the likelihood of soil compaction, non-uniform soil moisture, crusting and clodding.
- When tilling for seedbed preparation, a single pass just prior to planting will maximize moisture uniformity and minimize water loss from the seed zone compared to multiple passes.
- Each additional spring tillage pass increases the potential for soil erosion, compaction and excessive drying while also adding to production costs.
- If primary tillage was completed in the fall, consider no-till options for weed control and planting this spring.
- When tillage is necessary, choose the least aggressive implement and run it as shallow as possible to meet your objectives.
Michigan State University Extension research on tillage effects on soybean yields in Michigan has demonstrated that no-till cropping systems can yield as well as conventional systems. This spring, no-till may be an especially attractive option for growers thanks to a winter of multiple freeze-thaw cycles that loosened soils across the Midwest. It is important to consider how the timing and intensity of operations can be managed to minimize any negative impact.
The following links are provided by Michigan State University Extension for further reading:
Agronomist: Winter weather loosened soil; no-till a viable option -- Purdue Agriculture News
Spring Tillage Preparation -- Iowa State University Extension Integrated Crop Management News
Just Say No to Spring Tillage, NRCS Advises -- Carbon County, Utah Sun Advocate
Timing of Tillage Crucial to Crops -- Soil Science Society of America