2025
Soybeans inter-seeded with cover crops in Western North Dakota
Contributor/Checkoff:
Category:
Sustainable Production
Keywords:
Cover cropsSoil healthSustainability
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Leandro Bortolon, North Dakota State University-North Central Research Extension Center
Co-Principal Investigators:
John Rickertsen, North Dakota State University- Hettinger Research Extension Center
Chris Augustin, North Dakota State University-North Central Research Extension Center
Charlie Lim, North Dakota State University-Williston Research Extension Center
+2 More
Project Code:
NDSC_2025_Agronomy 16
Contributing Organization (Checkoff):
Institution Funded:
Brief Project Summary:
Soybean is increasing acreage in Western North Dakota in the past years and this trend will continue. Cover crop utilization is a great tool to reduce soil erosion, manage soil moisture, and weed suppression while improving soil health. In Western North Dakota, farmers face challenges with weed control specially Kochia, and also with the low soil cover after soybean harvest. Intersseding cover crops into standing soybeans is a well-investigated practice in Eastern North Dakota; however, there is a need for regional data for Western North Dakota farmers about intersseding cover crops into standing soybeans and its effect on weed suppression, soil cover, soybean yield, and return of the investment. Two trials will be implemented in four locations across Western North Dakota. Cover crops will be interseeded into standing soybeans in two different soybeans stages and we will consider two soybeans row spacing. Data from this regional study will be helpful to better understand the cover crops establishment after soybean harvest and its effects on weed suppression, soil cover, and soybean yield.
Information And Results
Project Summary

There is a lack of information regarding the impact of soybean yield when cover crops are established into standing soybeans in Western North Dakota. Weed control is becoming an issue and a more integrated approach to control weeds is necessary to improve herbicide efficiency, while increasing profitability. Also, soil erosion is a great issue in Western North Dakota due to little residue in the soil after soybean harvest. Winter hardy cover crops will be investigated as an option to increase soil cover after soybean harvest. The studies (two separate trials) will be conducted in four locations in western North Dakota (Minot, Williston, Dickinson, and Hettinger). We will consider two rows spacing, being narrow (7½-10”) and wide (22-30”). We will consider each row spacing as separate trials. The reason for investigating two rows spacing is that is a considerable number of farmers who use air-seeders and planters to plant soybeans. We will interssed cover crops into standing soybeans in two stages (R2 and R5).However, based on the study carried out in 2023, the moisture will also be considered to broadcast the cover crops.The reason for adding the moisture component to broadcast the seeds is to increase the chance of germination and establishment. Sometimes the soybeans were in the right stage, but little moisture to provide germination and establishment. Interseed cover crops at R2 stage is to provide more time for the cover crops to get established. The reason for interseed cover crops at R5 stage is because is close to the senescence and we can reduce the cover crop competition with soybeans. We will investigate five cover crops treatments: no cover crops; winter rye; winter rye + winter canola; winter rye + winter camelina; winter rye + oats + radish. Cover crops seeding rates will be at the recommended rates for cover crops establishment, and the seeds will be broadcast applied at the two soybean stages. All trials will be conducted using best management practices for Western North Dakota soybean production, and all trials will be under no-till. The experimental design will be a randomized complete block with four replications. Evaluations will be carried out before, during, and after trial establishment. For soybeans, we will evaluate plant population at harvest; yield; test weight; oil, and protein. For cover crops, we will evaluate soil cover (using the software Canopeo) and biomass 30 days after harvest, and in the spring (before burndown for the next crop); cover crop stand. For weed, we will evaluate weed presence/suppression in the fall and the spring, and the percentage of suppression will be calculated. In all trials we will calculate the return on the investment (ROI): we are going to calculate the ROI based on the equation: ROI = gross income (yield × commodity price) -treatment cost.

Project Objectives

Effects of cover crops interseeded into standing soybeans in Western North Dakota as an integrated tool to suppress weeds, increase soil cover, and improve soil health. We will measure the percentage of weed control and soil cover, and soybean yield to the cover crops treatments, and we will calculate the return on the investment by using cover crops.

Project Deliverables

The multi-location study will allow us to provide research-based recommendations regarding the time of implementing cover crops into standing soybeans in Western North Dakota, considering cover crop species and soybean row spacing.

Progress Of Work

Final Project Results

Benefit To Soybean Farmers

Results will help farmers from Western North Dakota to fill a research gap regarding intersseding cover crops into standing soybeans. Results will help farmers to decide what cover crops are more suitable for their operations, considering weed presence and soybean row spacing.

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.