2024
Soybeans Interseeded with Cover Crops in Western ND
Contributor/Checkoff:
Category:
Sustainable Production
Keywords:
AgricultureField management
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:
Project Code:
Contributing Organization (Checkoff):
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....
Unique Keywords:
#cover crops
Information And Results
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.

Project Objectives

Investigates the 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

Updated January 5, 2024:
Research Overview and Objectives
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 controlling 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.

The objective of this research is to investigate the 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 soil cover, and soybean yield to the cover crop treatments, and we will calculate the return on the investment by using cover crops.

The studies (two separate trials) were conducted in four locations in western North Dakota (Minot, Williston, Dickinson, and Hettinger). The study considered two rows spacing, being narrow (7½ - 10”) and wide (22-30”), and each row spacing was evaluated as separate trials. The reason for investigating two rows spacing is that there is a considerable number of farmers who use air-seeders and planters to plant soybeans. Cover crops were broadcasted into standing soybeans in two stages (R2 and R5). The reason for interseed cover crops at R2 stage is to provide more time for the cover crops to get established, and we can increase the chance of getting more moisture in the field for seed germination. The reason for interseed cover crops at the R5 stage is because it is close to the senescence and we can reduce the cover crop competition with soybeans, even though soil moisture at this stage is typically low for seed germination. We investigated five cover crop treatments: no cover crops; winter rye; winter rye + winter canola; winter rye + winter camelina; and winter rye + oats + radish. Cover crop seeding rates were at the recommended rates for cover crop establishment, and the seeds were surface broadcast applied at the two soybean stages.

All trials were conducted using best management practices for Western North Dakota soybean production, and all trials were under no-till. The experimental design was a randomized complete block with four replications.

Evaluations on soybeans were plant population at harvest; yield; test weight; oil, and protein. For cover crops, we evaluated: soil cover (using the software Canopeo) and biomass 30 days after harvest.
For weeds, we evaluated weed presence/suppression in the fall.

Completed Work: Deliverables and/or Milestones.
The trials were planted according to Table 1. All the trials were planted as planned. The evaluations cited in Table 1 such as soybean harvest, soil cover evaluation with Canopeo, cover crop biomass evaluation, and weed count were all done for all sites. We also have finalized the soybean oil and protein content and soybean test weight.

Table 1. Soybean Planting date, R2 and R5 stage, and harvest dates. Soil cover, cover crop biomass, and weed count dates.
Operation Minot Dickinson Williston§ Nesson Valley§ Hettinger
Planting June 2 May 19 June 6 May 29 May 18
R2 stage July 26 July 5 Aug 3 Aug 3 July 11
R5 stage Sep 15 Aug 22 - - Aug 22
Harvest Oct 16 Oct 25 - - Oct 6
Soil Cover Nov 17 Nov 21 - - Nov 21
CC Biomass Nov 17 Nov 21 - - Nov 21
Weeds count Nov 17 Nov 21 - - Nov 21
§ Dates missing for Williston and Nesson Valley due to the trial lost by hail

Progress of Work and Results to Date
The trials were well established in all locations across Western North Dakota. The excessive moisture during the spring imposed a challenge to plant the trials early in the season. On August 3 a severe hailstorm happened in northwestern North Dakota and the trials in Williston and Nesson Valley were lost. Cover crops were not established in Dickinson and Hettinger. The reason for the no establishment was related to the lack of moisture for the cover crop germination and establishment. In Minot, given the late planting date, the cover crops got more moisture after planting. However, most winter rye was properly established in both R2 and R5 stages. Percentage of soil cover and cover crop biomass data were collected in all trials. Weed counts were performed in all trials as well as planned in the project. The most common weed found was voluntary grains in very low incidence.
The results are still being processed for further analysis and they cannot be completed to present in this report.

Work to be Completed.
Data analysis for all variables in the trials must be completed in the months to come. Amino acids evaluation on soybean seeds will be analyzed in the weeks to come since we need to find a laboratory to run those analyses. In the spring (before burndown for the next crop) cover crop stand will be evaluated again. For weeds, we will evaluate weed presence/suppression in the spring before the burndown for the next crop, 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.

Other relevant information: potential barriers to achieving objectives, risk mitigation strategies, or breakthroughs.
We found that for Western North Dakota using the soybean stage only to define the time to seed the cover crops will impose risk for the cover crop establishment. In the second year of the study, we will couple the stage and moisture available to improve the chance of cover crop establishment.

View uploaded report 2 Word file

Final Project Results

Updated June 27, 2024:

View uploaded report Word file

Soil erosion is a major problem in Western North Dakota following the soybean harvest due to the low residue and stubble left in the soil. Keeping the soil covered is key to improving soil health by preventing soil losses by wind and runoff erosion. Interseeding cover crops into standing soybeans is an effective tool for implementing cover crops. 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 in North Dakota, especially Kochia. A combination of crop management practices to control weeds is necessary to increase profitability. This research aimed to investigate the effects of cover crops interseeded into standing soybeans in Western North Dakota on soybean yield. Field research was implemented in five locations across Western North Dakota. Cover crop trials were implemented in two soybean row spacing (narrow - 7½-10”; and wide - 22-30”). Cover crops were broadcasted into standing soybeans at the reproductive stage (R2 - full bloom; R5 - beginning seed). We investigated five cover crop treatments applied via surface broadcast at each soybean stage: no cover crops; winter rye; winter rye + winter canola; winter rye + winter camelina; and winter rye + oats + radish. Evaluations on soybeans were yield; test weight; oil, and protein. For cover crops, we evaluated: soil cover and biomass 30 days after soybean harvest. Soil moisture was evaluated at the same time as cover crops at 0-3” and 0-8” soil depth. The return on the investment (ROI) was calculated based on the equation: ROI = gross income (yield × commodity price) - treatment cost. Cover crop cost-sharing program was considered to calculate ROI. Interseeding cover crops into standing soybeans in western North Dakota does not affect soybean yield. The establishment of cover crops is highly dependent on soil moisture and precipitation pattern. Cover crop biomass increased soil cover even with low amounts of biomass observed across locations. Soil moisture was not affected by cover crops across all locations. The ROI using cost-sharing program can offset the cost for farmers to use cover crops with soybeans. More research must be carried out to investigate the cover crop seeding time and seeding rate to achieve the desired cover crop population and yield. Crop yield in the crop followed by cover crop must also be investigated in western North Dakota.

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.