2017
Increasing Soybean Yield by Enhancing Seed Fill
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Contributor/Checkoff:
Indiana Soybean Alliance
Category:
Sustainable Production
Keywords:
Field management Nutrient managementSoil healthTillageYield trials
Parent Project:
Increasing Soybean Yield by Enhancing Seed Fill
Lead Principal Investigator:
Shaun Casteel, Purdue University
Co-Principal Investigators:
Project Code:
Contributing Organization (Checkoff):
Indiana Soybean Alliance
$79,820
Institution Funded:
Purdue University
$79,820
Brief Project Summary:

Modern soybean cultivars are more active later in the growing season than older cultivars, especially in regard to leaf retention, accumulation of nitrogen (N), phosphorus (P), and sulfur (S), and remobilization of N, P, and S. These advancements join together to improve yield and nutrient removal. Project objectives are to: determine the duration and the rate of seed fill during late soybean development, especially after R6 (full seed) until harvest; and determine the opportunities to enhance seed fill (e.g., higher daily gain, extended seed fill duration), thus improving grain yield through synergies in nutrient supply and foliar protection.

Key Benefactors:
farmers, agronomists, Extension specialists

Information And Results
Final Project Results

Update:
refer to final results

The greatest yield response in the MG II study was in the combination of enhanced fertility (sulfur and phosphorus) plus the prophylactic application of fungicide and insecticide (i.e., TSP+AMS+R4) across the two years of the study. The effective seed filling period (EFP) was the main driver in 2016 since the seed growth rates were comparable across management treatments and the EFP was 5 d longer for TSP+AMS+R4. Seed size was also marginally higher in the same treatment. In 2017, the EFP also drove the improvements in grain yield (and marginally seed size). In the MG III study, the greatest yield effect in 2016 was TSP+AMS+R4. However, the source of yield improvement seems to be more related seed growth rate (SGR) than the duration of the effective seed filling period. Little differences were noted in 2017, since SGR and EFP were similar across the 3 intensely sampled management treatments. Thus, no major yield improvements were noted. Management can improve the seed fill period of soybean. Preliminary conclusions are that the combination of enhanced fertility (sulfur and phosphorus) and foliar protection provided greater benefit to the shorter season varieties than the fuller season varieties. In other words, the management extended the critical seed filling window of the shorter season varieties to utilize more of the season (e.g., sunlight, heat units). Whereas, the fuller season varieties are already utilizing the growing season that they are adapted to grow in. The yield improvement target for full season varieties would be to increase the rate of seed fill. Further investigation into the interactions of maturity group, sulfur supply (and potentially phosphorus), planting date, and foliar protection will help to decipher the instances of increasing in seed fill rate vs. extending seed fill window, and ultimately, yield.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.