Effect of Vertical and Strip-Tillage on Corn and Soybean Grain Yield
April 9, 2024
TRIAL OBJECTIVE
- Possible benefits of vertical tillage include improvements in seedbed, root growth, and water infiltration while preventing compaction layers in the soil profile.
- Vertical tillage can also help with residue management, especially in reduced tillage systems where the accumulation of biomass in the soil surface can impede the correct planter operation and keep soil temperatures lower, delaying emergence.
- The objective of these trials was to determine the effect of vertical tillage on corn and soybean yield compared to other tillage practices such as strip-till and no-till.
RESEARCH SITE DETAILS
- The trial design was a randomized complete block with four replications and four tillage treatments:
- Vertical-till at 0 degrees gang angle
- Vertical-till at 6 degrees gang angle
- Strip-till
- No-till
- Both trials (corn and soybean) were planted next to each other using the same experimental design. The Bayer products used were a 111 relative maturity (RM) corn and a 2.5 maturity group (MG) soybean.
- Strip-till and vertical-till were conducted on 05/01/2023 and 05/03/2023, respectively, according to treatments.
- Zero to 3 inch and 3 to 6 inch composite soil samples were taken from each plot in the corn experiment on 05/22/2023 (Table 1).
- The trial received a 2 x 2 starter fertilizer application of 29 lb/acre nitrogen (N), 60 lb/acre P2O5, 25 lb/acre sulfur (S), and 0.25 lb/acre zinc (Zn) at planting across all treatments. Both crops were planted in 30 inch rows.
- Nitrogen was side-dressed across all corn plots using 360 Y-DROP® nozzles at a rate of 150 lb/acre on 06/21/2023.
- Two pictures per plot were taken at planting on the corn experiment for soil coverage classification. The software used was the Stover App from Kansas State University.
- Weeds were uniformly controlled with herbicides and no other pesticides were applied.
- Plots were combine-harvested with grain moisture content, test weight, and total weight collected. Statistical analysis for Fisher’s Least Significant Difference was performed.
UNDERSTANDING THE RESULTS
Corn Trial
- Several soil test results were affected by tillage treatment, especially in the first 0 to 3 inches of soil. Soil samples were taken 19 to 21 days after the tillage operation (Table 1).
- With more soil disturbance (strip-till and vertical-till at 6 degrees) there was higher nitrogen mineralization. However, increases in phosphorus and potassium levels were only seen under strip-till.
- The average percentage of soil covered by residue was similar under no-till (66%) and vertical-till at 0 degrees (69%) (Figure 1). Tilling with no angle cut the residue but most of it was left on the surface.
- A statistically significant difference was observed when comparing residue coverage between vertical-till settings. Plots tilled at 6 degrees had less than half of the residue coverage compared to the same equipment but at 0 degrees (28% and 69%, respectively).
- Although no statistically significant effects were found on corn yield between tillage treatments (Figure 3), yield was numerically the highest on plots where vertical-till was done at a gang angle of 0 degrees (198.5 bu/acre). The lowest average yields were achieved using the same equipment but at 6 degrees (179.4 bu/acre). It is important to select the appropriate equipment settings depending on the specific objective.
- Corn yield was on average 8.7 bu/acre higher under no-till compared to strip-till.
- Soil nutrient differences observed between tillage treatments early in the season (Table 1) did not impact in yield. It is important to notice that those lower levels in plots with less soil disturbance were still sufficient to sustain early plant growth. Also, all plots received starter fertilizer at planting.
- No statistically significant results were obtained when looking at corn plant heights at the V5 to V6 growth stage (Figure 4). Corn plants tended to be taller in vertical tilled plots with a gang angle of 6 degrees (24.3 inches). Strip-till and no-till obtained similar plant heights (23.5 and 23.2 inches, respectively) but slightly lower than vertical-till at 6 degrees. The shortest plants were measured under vertical-till at 0 degrees (22.2 inches).
Soybean Trial
- The effects on average soybean yield between tillage treatments were similar to the effects observed in the corn trial. Vertical-till plots at 0 degrees obtained the highest yield (48.3 bu/acre) but the difference was not statistically significant (Figure 5).
- Small differences in soybean yield were observed between no-till, strip-till, and vertical-till at 6 degrees.
KEY LEARNINGS
- Vertical tillage at a gang angle of 0 degrees tended to obtain the highest yields in both corn and soybean studies, though the result was not statistically significant. No numerical yield advantage was detected in plots where the equipment was set up at 6 degrees.
- Nutrients such as nitrogen were more available at planting in tilled plots. The effect was more noticeable under strip-till and vertical-till at 6 degrees. However, this availability did not impact the average yield in these experiments.
- The percentage of soil that was covered by residue at planting was similar in plots under vertical-till and no-till. Residue cover is important when preventing wind and water erosion.
- More research is needed to assess the long-term impacts of vertical tillage on soil test properties.
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