December 22, 2020
TRIAL OBJECTIVE
- Each planting season there are soybean fields in the South with unintentionally high plant populations due to equipment or operator planting errors.
- Previous work has shown that high populations of soybeans can be more susceptible to lodging. Soybean plants are also typically capable of overcoming many stand deficiencies including skips, missing rows, and non-uniform emergence.
- This study was conducted to evaluate the effectiveness of using conventional techniques to remediate excessive seeding rate planting errors and to reinforce previous work on the compensatory ability of soybean. Two primary questions were asked:
- Should/can overplanted soybean populations be reduced?
- Do soybean products continue to demonstrate the ability to compensate for missing plants, skips in stands, and missing rows?
RESEARCH SITE DETAILS
| Location | Scott, MS | ||
| Soil Type | Mixed silt loam | ||
| Previous Crop |
Cotton | ||
| Tillage Type |
Conventional |
| Planting Date | 5/2/20 | ||
| Harvest Date | 10/2/20 | ||
| Potential Yield (bu/acre) |
80 | ||
| Seeding Rate (seeds/acre) |
120K, 360K |
- All agronomic inputs were per local standards.
- Two Asgrow® soybean products were planted:
- AG46X0 Brand
- AG48X9 Brand
- Two seeding rates were used for this study:
- Standard: 120,000 seeds/acre
- High: 360,000 seeds/acre
- Remediation treatments were applied at three weeks post planting:
- UTC 120K: Untreated control (UTC) planted at 120,000 seeds/acre with NO remediation treatment applied (Figure 1).
- UTC 360K: Untreated control planted at 360,000 seeds/acre with NO remediation treatment applied (Figure 1).
- Bed Conditioner: Planted at 360,000 seeds per acre and one pass with a conventional bed conditioner to attempt to reduce standing plant number (Figure 2).
- Plowed: Planted at 360,000 seeds per acre and Orthman bedder run at an angle across the rows to non-uniformly reduce the standing population. Rows were rerun for irrigation and drainage. This resulted in large 3- to 4-foot skips distributed uniformly across the plot area (Figure 3).
- Rotary Hoe: Planted at 360,000 seeds per acre and one pass with a conventional rotary hoe to attempt to reduce standing plant number (Figure 4).
- Spray Out 1:1: Planted at 360,000 seeds per acre and a broad-spectrum herbicide applied to every other row to result in a 1:1 skip row (76-inch row spacing) (Figure 5).
- Plots were single replicate strip plots of approximately 0.2 acre.
- Post-treatment stand counts were taken on representative plot areas to quantify stand.
- Yields were collected using commercial harvest equipment with the Climate FieldView™ Platform digital app and Precision Planting® YieldSense™ yield monitoring systems.
Figure 1. High vs standard population soybean: untreated control soybean plots planted at 120,000 seeds/acre (left) and 360,000 seeds/acre (right).
Figure 2. Bed conditioner vs high population: bed conditioner treatment (left) and untreated soybeans planted at 360,000 seeds/acre (right).
Figure 3. Soybean planted at 360,000 seeds per acre and plowed with an Orthman bedder run at an angle across the rows to non-uniformly reduce the standing population.
Figure 4. Soybean planted at 360,000 seeds per acre and remediated with one pass with a conventional rotary hoe.
Figure 5. Soybean planted at 360,000 seeds per acre and a broad-spectrum herbicide applied to every other row to result in a 1:1 skip row (76-inch row spacing).
UNDERSTANDING THE RESULTS
Figure 6. Effect of planter error remediation treatments on average soybean stand count in 2020.
Figure 7. Effect of soybean planting error remediation treatments on stand counts of Asgrow® soybean products in 2020.
- The rotary hoe treatment did not substantially reduce standing plant populations and in some cases, increased plant population (Figures 6 and 7).
- The bed conditioner treatment reduced the stand (Figures 6 and 7) but did not increase average yield compared to the untreated control with either the standard or high seeding rates (Figures 8 and 9).
Figure 8. Average yield response of Asgrow® soybean products combined over planting error remediation treatments in 2020.
Figure 9. Response of Asgrow® soybean products to planting error remediation treatments in 2020.
- There was little difference in average yield response observed across the study (Figures 8 and 9).
- Similar to previous work, the remediated soybean plots were able to compensate for lower plant populations even with an entire row missing in the Spray Out 1:1 treatment (Figures 8 and 9).
- As in previous studies, the soybean plants were also able to almost completely compensate for 3- to 4-foot skips in the field as created in the plowed treatment (Figures 8 and 9).
KEY LEARNINGS
- None of the stand reduction treatments were necessary in this case. Despite the excessively high planting error of 360,000 seeds/acre, the soybeans were best left without remediation.
- Little yield response to population or stand variability was observed across the study. This is similar to previous results from the Scott Learning Center.
- In 2020, soybeans maintained the ability to compensate for large amounts of variability across the field whether with missing rows or large skips in this simulation.
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