A summary of tillage effects on soybean yields in Michigan (2010 and 2011)

Local and current research can help Michigan soybean producers understand how various tillage operations affect soybean yields.

The quantity and quality of the corn stalks remaining following harvest operations has increased in recent years. This situation has led to damaged tires, decreased planter and drill performance and delayed soil drying and warming in the spring. Tillage is one of the options for managing corn residue prior to planting soybeans. This article summarizes the results from eight Michigan on-farm research trials evaluating tillage effects on soybean yields.

Case Turbo Disk 330 versus no-till

The Case Turbo Disk 330 was compared to no-till in three trials in central Michigan in 2010 and in two trials in 2011. At all locations, the treatments were replicated four times and tillage implements were run in the spring just prior to planting. Both the no-till and the vertical tillage treatments were planted with equipment designed to handle no-till conditions.

When the three trials conducted in 2010 were combined, the Case Turbo Disk treatment increased yield by 2.2 bushels per acre when compared to the no-till. However, when the 2011 trials were combined and analyzed, the vertical tillage yield and the no-till yield were not significantly different from each other. White mold pressure was much higher in the tilled treatment than the no-till treatment at the Clinton County trial. When all five trials were combined and analyzed, the average yield for the Case Turbo Disk was 1.7 bushels per acre higher than the no-till treatment. The quick economic analysis presented in Table 1 shows that the Case Turbo Disk generated approximately $8 per acre more than the no-till treatment when all five trials were combined.

Table 1. Case Turbo Disk effects on soybean income in 2010 and 2011

No-till

Case Turbo Disk

Yield (bu/ac)

48.1

49.8

Gross Income ($/ac)

$545

$563

Tillage Costs ($/ac)

$0

$10

Gross Income – Tillage Costs

$545

$553

Assumptions: Soybean market price of $11.30 per bushel.
Soybean seed costs of $50 per 140,000 seeds.

2011 Center for Excellence tillage trial

Five tillage treatments (an in-line ripper, a disk ripper, strip tillage, vertical tillage and no-till) were compared at the Center for Excellence in Lenawee County in 2011. Figure 1 clearly shows that there were no significant differences in the yields for the tillage treatments in 2011 at this location.

Figure 1. Tillage implement effects on soybean yields at the Center for Excellence in 2011
Tillage chart

Salford RTS versus no-till

The Salford RTS vertical tillage implement was compared to no-till at two locations in 2010. The Salfort RTS was run in the spring prior to planting and all treatments were planted with no-till planters or drills. When both trials were combined and analyzed, tillage did not significantly affect soybean yields (Figure 2).

Figure 2. Salford RTS effects on soybean yields in 2010
Tillage chart

Dawn Pluribus strip tillage versus no-till

Fall and spring strip tillage treatments were compared to no-till at one location in southwest Michigan. The strip tillage treatments were performed using a Dawn Pluribus Strip-till operating on 30-inch centers. The strip tillage treatments produced higher soybean yields (Figure 3) and higher soil temperatures (Figure 4) than the no-till treatment. Based on the results from this trial, strip tillage looks promising for soybean production in 30-inch rows. However, strip tillage should be restricted to fields having slopes less than 5 percent to reduce the potential for water erosion occurring in the rows.

Figure 3. Strip tillage effects on soybean yields in 2011
Tillage chart


Figure 4. Strip tillage effects on soil temperatures on May
Tillage chart

Tandem disk versus no-till

A single pass of a tandem disk was compared to no-till at one location in Hillsdale County in 2011. The tandem disk was operated in the spring just prior to planting and both treatments were planted with a no-till drill. The soybean yields in the tandem disk treatment averaged 3.4 bushels per acre higher than those in the no-till treatment. However, due to the variability in the field, the yield difference between the two treatments could not be attributed to tillage with a high degree of confidence.

Historically, the effects of tillage on soybean yields have been relatively small and may not offset the additional fuel, labor and depreciation costs. Tillage operations will reduce residue cover exposing soils to wind and water erosion. So producers that farm highly erodible land should check with their local Natural Resources Conservation Service office to make sure that the tillage operations they want to perform comply with their conservation plan.

This article was produced by the SMaRT project (Soybean Management and Research Technology). The SMaRT project was developed to help Michigan producers increase soybean yields and farm profitability. Funding for the SMaRT project is provided by MSU Extension and the Michigan Soybean Checkoff program