2022
Optimizing Residual Herbicides to Manage Pigweeds in Early Planted Soybeans
Home
Contributor/Checkoff:
Kansas Soybean Commission
Category:
Sustainable Production
Keywords:
AgricultureCrop protectionHerbicide
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Sarah Lancaster, Kansas State University
Co-Principal Investigators:
Project Code:
2201
Contributing Organization (Checkoff):
Kansas Soybean Commission
$41,071
Institution Funded:
Kansas State University
$41,071
Brief Project Summary:
Kansas farmers have requested information to help manage weeds in early-planted soybeans. This project will identify how soybean planting date influences the effectiveness of common residual herbicides used in both 15- and 30-inch row spacings. Researchers will compare the duration of weed control by residual herbicides in soybeans prior to the crop insurance initial planting date (early) to soybeans planted shortly after the initial planting date (late). They will quantify the benefit of layered residual herbicides in terms of weed control and weed seed production when soybeans are planted early vs late, and compare profitability among evaluated treatments.
Key Beneficiaries:
#agronomists, #applicators, #extension specialists, #farmers, #weed specialists
Unique Keywords:
#herbicides, #planting, #profitability, #residual herbicides, #weed control, #weed management
Information And Results
Project Summary

This project is evaluating interactions of planting date, row spacing, and residual herbicide programs on weed control and yield in soybeans at three locations in Kansas.

Project Objectives

1. Compare the duration of weed control by residual herbicides in soybeans planted in 15” and 30” rows prior to the crop insurance initial planting date (early) to soybeans planted shortly after the initial planting date (late).
2. Quantify the benefit of layered residual herbicides in terms of weed control and weed seed production when soybeans are planted early vs late in 15” and 30” rows.
3. Compare profitability among treatments evaluated.
4. Evaluate on-farm use of residual herbicides through a survey.

Project Deliverables

This research will provide research-based information to farmer questions and will help understand how to manage herbicide-resistant Palmer amaranth in ways that slow the development of resistance to Group 15 herbicides. The budget and economic analyses will provide information on the profitability of the factors included in the study. This information will be shared with farmers through media outlets including newsletters, presentations, and field days.

Progress Of Work

Update:
Studies are in place at Manhattan, Ottawa, and Scandia. Planting was delayed in some locations due to weather and equipment challenges.

Final Project Results

Updated August 15, 2024:
Field trials were completed. Data were reported at field days in Ottawa and Scandia (handout attached). A graduate student was identified to complete year 2 of the study. In addition, we collaborated with other scientists to explore the use of remotely-sensed data to quantify weed cover (poster and abstract attached).

View uploaded report PDF file

View uploaded report 2 PDF file

View uploaded report 3 Word file

Results after one year (three locations) of data suggest that there were no difference is waterhemp or Palmer amaranth control associated with planting date, row spacing, or residual herbicide selection. Weed control was excellent in all experimental treatments. Canopy cover did vary across locations. In Manhattan (the earliest planted), there were no differences in canopy cover. In Scandia, the northern-most location and the only irrigated location, canopy cover in early August was 76 to 93% ranked as follows: Late-planted 30" rows < Early-planted 30" rows < Early-planted 15" rows = Late-planted 15" rows.

Benefit To Soybean Farmers

Data-based weed management recommendations that are appropriate for current production practices.

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.