Response of Soybean Varieties on Calcareous Soils
Response of Soybean Varieties on Calcareous Soils
TRIAL GOALS
As soybean farmers gauge chlorosis response of soybean products to calcareous soils and growing conditions, soybean product selection is one of the most efficient management tools to combat iron deficiency chlorosis (IDC) in soybean production.
This research evaluated nine commercially available soybean products for tolerance to IDC in order to provide updated information on soybean product responses. The study’s objective was to determine local soybean products with greater tolerance to IDC and gain perspective of product IDC ratings for the Central Plains region.
STUDY INFORMATION
- Trial location was identified based on the occurrence of IDC in previous soybean crops as observed by the farmer cooperator. The previous crop was double-crop corn.
- Weeds were controlled uniformly across the study.
- Irrigation was estimated as 8 inches for the crop growing season.
- Soil pH ranged from 8 to 8.2.
- The study was a strip-trial design evaluating nine Channel® soybean products.
- Plots consisting of six rows of soybeans were planted into 30-inch rows at a depth of 1.5 inches.
- A 9-point scale was employed to score the severity of IDC symptoms:
- 1 = Excellent – green, no yellowing
- 2 = Very Strong – little to no yellowing
- 3 = Strong – minimal yellowing
- 4 = Average – mild yellowing
- 5 = Above Average – moderate interveinal chlorosis
- 6 = Below Average – pronounced interveinal chlorosis
- 7 = Weak – severe interveinal chlorosis
- 8 = Very Weak – predominantly yellow
- 9 = Poor – dead meristems or plants
| Location | Assaria, KS |
|---|---|
| Soil Type | New Cambridge silty clay |
| Previous Crop | Corn |
| Tillage Type | Conventional |
| Planting Date | 6/21/21 |
| Harvest Date | 10/20/21 |
| Potential Yield (bu/acre) | 80 |
| Seeding Rate (seeds/acre) | 150,000 |
Table 1
| Channel® Brand Soybean Product | Trait | Maturity Group | Harvest Moisture (%) | Test Weight (lbs/bu) | Average Yield (bu/acre) | Iron Deficiency Chlorosis (IDC) Rating |
|---|---|---|---|---|---|---|
| 3222RXF | XtendFlex® Soybeans | 3.2 | 10.1 | 53.2 | 61.4 | Strong |
| 3322RXF | XtendFlex® Soybeans | 3.3 | 9.3 | 58.5 | 49.6 | Above Average |
| 3622RXF | XtendFlex® Soybeans | 3.6 | 9.1 | 59.6 | 59.4 | Average |
| 3721RXF/SR | XtendFlex® Soybeans with Sufonylurea (SR) herbicide resistance | 3.7 | 9.2 | 56.2 | 56.5 | Average/Above Average |
| 3922RXF/SR | XtendFlex® Soybeans with Sufonylurea (SR) herbicide resistance | 3.9 | 9.6 | 57.4 | 57.7 | Below Average |
| 4121RXF/SR | XtendFlex® Soybeans with Sufonylurea (SR) herbicide resistance | 4.1 | 9.6 | 59.1 | 56.6 | Strong |
| 4320RXF | XtendFlex® Soybeans | 4.3 | 9.6 | 59.9 | 60.8 | Above Average |
| 4422RXF/SR | XtendFlex® Soybeans with Sufonylurea (SR) herbicide resistance | 4.4 | 10.1 | 56.6 | 57.4 | Average |
| 4720RXF | XtendFlex® Soybeans | 4.7 | 12.7 | 49.4 | 63.7 | Above Average |
BREAKING DOWN THE RESULTS
- All soybean products tested showed IDC tolerance at some level. Yield differences between soybean products are due to relative maturity as well as IDC rating.
- Overall, soybean yielded well despite the extended periods of drought in the area during the 2021 growing season.
- Seasonal rainfall accumulation was 27.6 inches, approximately 4 inches less than the 10-year average.
- Farmers applied irrigation more often this year as compared to the last three years in this field.
SUMMARY OF RESULTS
Here are some key takeaways from this study:
- All the soybean products in this study exhibited some level of tolerance to IDC. The difference in one product to the next is a result of a complex interaction between plant physiological response to soil characteristics, topography, weather and irrigation practices. Screening soybean products for IDC is critical for farmers with fields with a history of IDC.
- Reduced plant growth due to any IDC symptoms can have a negative effect on yield potential. Significant yield reductions have been attributed to IDC throughout the north central United States. Planting soybean products with higher IDC tolerance is an effective technique to protect against yield losses related to IDC.
- Correcting IDC can be very difficult, and the most important management consideration is to identify products with greater IDC tolerance to minimize plant stress. Selecting the best soybean product for fields with a history of IDC decreases plant death rates and increases the likelihood of plants to recover from IDC.