Soybeans are a familiar crop for North Dakota producers with almost 7.0 million acres planted in 2024 (USDA Agricultural Statistics Service). Close to all of this acreage will be harvested for grain. Soybean can be a viable forage crop that can produce good yields and high quality. Work by Hintz and coworkers in the 1980s with grain type soybean varieties reported yields of 1.0-3.0 T/ac with crude protein levels ranging from 18-20% which is similar in quality to alfalfa. Rogers (unpublished data) in 2024 collected forage soybean yields of 1.28-1.6 T/ac but when combined with a sorghum-sudangrass hybrid yields increased to 1.4-3.0 T/ac without nitrogen fertilizer. Sorghum sudangrass alone with the benefit of nitrogen fertilizer produced 1.1-2.7 T/ac of forage biomass. Soybean forage quality data collected by Rogers has averaged 16% crude protein. Grain type and forage type soybeans have been found to have similar yields, but grain types can have greater pod formation at harvest, resulting in higher crude protein and lower fiber concentration (Sheaffer, et al., 2001).

Forage soybeans has the potential to produce a quality forage similar to alfalfa and can be mixed with other forage crops to improve forage quality. Because it is a legume it can reduce or eliminate the need for nitrogen fertilizer thereby reducing input cost, increasing sustainability and reducing potential for nitrogen runoff. Being an annual, it will fit into current crop rotations easily with similar agronomic production practices that are used for soybean grain production. More work needs to be done to further evaluate the compatibility of forage soybeans with other crops and the effect on total yield, forage quality and economic viability. Therefore, this project is proposed to evaluate the inclusion of forage soybeans as a viable forage crop either in a monoculture or mixtures for North Dakota producers.

1. Measure forage yield of forage soybean mixed with spring forage barley, spring forage oats, winter rye, or sorghum sudan grass in comparison to monocultures of each.
2. Evaluate forage nutrient content of forage soybean mixtures compared to forage monocultures.
3. Evaluate the effect of a May, June, or July planting date on forage production.
4. Subject the agronomic results to an economic analysis to determine the economic viability of this system compared to alternative systems.
5. Evaluate the use of a hay tedder to reduce field drying time of forage soybean-sorghum sudangrass mixtures for hay on a field scale.

Research results will be communicated through presentations at field days, producer meetings, news releases, social media, popular press, and presentations at national meetings. The major benefit to North Dakota producers will be the availability of a reliable, productive warm season annual legume that is competitive and compatible to be grown alone or in grass mixtures. Soybeans can potentially reduce input cost, and improve forage quality for producers. As an annual it fits well into existing North Dakota production systems and crop rotations.

Soybean farmers will benefit from this work in a number of ways. Data will be generated on the inclusion of winter cereal rye with soybeans at the time of planting and the effect it has on yield. This can then be extrapolated on the inclusion of cereal rye with grain type soybeans at the time planting and the benefit of the inclusion of rye to act as a winter cover crop following grain harvest. This project will also demonstrate the use of soybeans as a legume companion crop in forage mixtures. This can open up alternatives uses for soybeans not only as a grain but as a forage crop as well.