Vertical tillage effects on soybean yields in Michigan

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

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. Vertical tillage is one of the conservation tillage options for managing corn residue prior to planting soybeans. This article summarizes the results from five Michigan on-farm research trials evaluating the effects that two different vertical tillage implements had on soybean yields.

In all cases, the untilled control was not tilled prior to planting soybeans, but had been tilled prior to planting corn the previous year and therefore should not be considered no-till. All vertical tillage operations were performed in the spring into untilled corn stalks and all treatments were planted with no-till planters or drills.

Salford RTS versus an untilled control

The Salford RTS vertical tillage implement was compared to an untilled control at two locations in 2010 and one location in 2012. When the 2010 trials were combined and analyzed, tillage did not significantly affect soybean yields (Table 1).

Table 1. Salford RTS effects on soybean yield in 2010 (two sites)

Treatment

Yield (bu/ac)

Untilled control

50.8 a

Salford RTS

51.5 a

C.V.%

1.7

LSD 0.1

0.8

However, in 2012, a single pass of the Salford RTS did significantly increase soybean yields by 2.5 bushels per acre over the untilled control at one location near Hamilton, Mich. (Table 2).

Table 2. Salford RTS effects on soybean population and yield in 2012 (one site)

Treatment

Population (plants/ac)

Yield (bu/ac)

Untilled control

173,659 a

56.4 b

Salford RTS

169,884 a

58.9 a

C.V.%

5.0

2.1

LSD 0.1

14,175

2.0

When all three sites were combined and analyzed, the yield advantage produced by the Salford RTS was statistically significant, but was reduced to 1.3 bushels per acre (Table 3). The Salford RTS produced an additional $8 per acre more income than the untilled control when all three sites were combined (Table 3).

Table 3. Salford RTS effects on soybean yield and income in 2010 and 2012 (three sites)

Treatment

Yield (bu/ac)

Income ($/ac)

Untilled control

52.7 b

$751

Salford RTS

54.0 a

$769

C.V.%

1.9

 

LSD 0.1

0.7

 

Assumptions: Soybean market price of $14.25 per bushel; Salford RTS costs = $10 per acre

Sunflower 6630 versus an untilled control

The Sunflower 6630 vertical tillage implement was compared to an untilled control at two locations in 2012. The Sunflower 6630 increased soybean yields by 2.8 bushels per acre in Monroe County, but decreased soybean yields by 6.8 bushels per acre in Hillsdale County (Table 4). The Sunflower 6630 increased income by $30 per acre in Monroe County, but reduced income by $107 per acre in Hillsdale County (Table 4). Plant populations were not affected by tillage at either location. The Hillsdale County site was planted on a coarser-textured soil and was planted 12 days later than the Monroe County site. These factors combined with the drought conditions may have contributed to the reduced yields in the Sunflower 66330 treatment at the Hillsdale County site.

Table 4. Sunflower 6630 effects on soybean populations, yields and income in 2012

 

Monroe County

Hillsdale County

Monroe County

Hillsdale County

 

Treatment

Population (plants per acre)

Yield (bu/ac)

Income ($/ac)

Yield (bu/ac)

Income ($/ac)

Untilled control

174,240 a

125,235 a

43.0 b

$613

47.0 a

$670

Sunflower 6630

179,757 a

120,592 a

45.8 a

$643

40.2 b

$563

C.V.%

7.6

3.1

2.4

 

3.7

 

LSD 0.1

22,521

6,284

2.2

 

3.3

 

Assumptions: Soybean market price of $14.25 per bushel; Sunflower 6630 costs = $10 per acre

Historically, the effects of tillage on soybean yields have been relatively small and may not offset the additional fuel, labor and depreciation costs. Research results from more locations and more years are needed to determine if vertical tillage consistently improves soybean yields and profitability in Michigan.

Tillage operations will reduce residue cover exposing soils to wind and water erosion. 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.

Related MSU Extension article

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. SMaRT is a partnership between Michigan State University Extension and the Michigan Soybean Checkoff program.