Based on initial observations of cereal rye use in southeast ND, we expect to find that it is an effective tool for managing soil salinity, and thus improving soybean productivity in saline threatened soils. The mechanisms behind these suspicions are presumed to be both direct and indirect, through the management of soil, water, prevention of salt migration, increase in soil water holding capacity through organic matter contributions, and protection of the soil from desiccating winds. Through this study, we also expect to find that cereal rye will substantially contribute to building overall soil health and managing weeds (including herbicide resistant weeds of concern). We anticipate that soybean aphids and other insect pests will be suppressed in response to cereal rye presence. However, it is not clear what to expect from natural enemies (beneficial insects) and potentially new insect pest species. We expect that these findings will not be universal across space and time, and that we will successfully identify conditions required for optimizing soybean productivity across a range of limitations.

Updated July 4, 2018:

View uploaded report

In 2017, we initiated a study to see if we can use a cereal rye cover crop to improve soybean and corn production on saline soils. Soil salinity is a common cause of poor crop yield throughout North Dakota, and we need effective strategies for improving the soil health and productivity of salty soils. Cover crops have a lot of soil health benefits, and we think they can help improve productivity in saline soils, but they might also compete with the cash crop or encourage pests (See Figure 1 in attached report).

Our goals for this research:
(1) Understand the differences in soils, plant growth, and insects in moderately saline soils (soils with an electrical conductivity between 2-4 dS/m).
(2) Test if a cereal rye cover crop in a soybean-corn rotation can improve soil health and crop productivity without introducing too many risks.

We established cover crop trials on four farms that all have patches of salty soil (in Aneta, Jamestown, and Northwood). We surveyed the soil for salts and inter-seeded cereal rye (40 lbs/ac) in strips across the field so that we have sampling points with and without cover crop and with and without salts (Figure 2). In the first year of the study, we collected baseline soil data, measured yield, and surveyed insects. We’ll continue to measure these for three more years, since it takes time for the soil to change.

In 2017, crops on the saline soils had lower yields, and the cereal rye did not further reduce yields. Saline soils often occur in landscape depressions, so they are also consistently wetter throughout the growing season; the cover crops did not necessarily dry out the soil in the Fall. Since there is less plant growth and more water in saline soils, there’s a chance that the saline patches contain unused nutrients (like nitrogen and phosphorus). In the next few years of the project, we’ll continue measuring these properties, and we’ll be measuring the different organisms that live in the soil and in the plant canopy, to see if they are good or bad, and if they change in the areas that have cereal rye.

We still have a lot to learn about cereal rye as a tool for managing soil salinity. In addition to understanding salt management, this research will also help us understand the uses and limitations of cereal rye for improving soil health and crop yield.