Cover crops once established, suppress and compete with weeds for its entire duration in the field, and not too dependent on temperature and weather conditions as when applying herbicides to control weeds. Cover crops can also compliment herbicides for weed control. Experiments conducted at NDSU North Central Research Center showed that the combination of a fall cover crop (cultural) and herbicide (chemical) as integrated weed management strategy reduced kochia density by more than 70% (Endres, 2022), leaving chemical weed control programs implemented into the growing season with better spray coverage on smaller weeds thereby effective in weed control. A four-year study conducted at CREC showed excellent (up to 99%) control of green foxtail and common lambsquarters when cereal rye alone was used as a fall cover crop in front of dry bean, although dry bean yield was reduced when cover crop was terminated close to or after dry bean planting (Endres, 2022). However, use of cereal rye as a cover crops in northwestern ND to manage weeds annual weeds that emerge in the fall or early in the spring, especially in dryland no till situations where soil moisture is generally thought as the limiting factor in planting a cover crop after the harvest season, has not been thoroughly investigated. Limited yearly precipitation can deter growers to adopt a cover crop program preceding soybean due to soil moisture concerns, either not enough moisture for cover crop germination in the fall or the overwintering cover crop such as rye takes up the moisture in the spring that soybean yield could get affected. Northwestern, ND receives an average precipitation (rain and snowfall) of 13 inches, with about 2-3 inches fall as rain in the summer months. Additionally, herbicide-resistant kochia populations, particularly to group 9, group 2, and group 14 herbicides have been a huge concern in recent years especially in western ND (Ikley, 2023; Jenks, 2023). With the growing problems brought about by weed resistance to herbicides, and the slow turnover for new herbicide modes of action, there is a need for a diversified and integrated approach to control and manage weeds and soil weed seedbanks. In wetter regions of North Dakota and in eastern states which receive far more precipitation, rye planted in the fall has been shown to provide control or suppression of weeds that emerge late in the fall and weeds that emerge very early in the following spring (Werle, 2018). However, there is limited information regarding the use of rye as a fall cover crop in combination with fallor spring-applied herbicides and their effect on kochia under the climatic and moisture
conditions of northwestern ND.

This study aims to determine the effects of increasing seeding rates of a fall rye in conjunction with a fall- and spring-applied pre-emergence herbicides on kochia control
(and possibly green foxtail control), available soil moisture, and soybean yield in no till dryland field conditions in northwestern ND.

This study aims to provide recommendations for optimum rye seeding rate in conjunction with herbicide use for weed control, and to give light the trade off in soybean yield (if any) when used in western ND

This study also hopes to promote soil conservation practices and soil benefits from the use of cover crops such as rye, where applicable. Results from this study will be presented to grower and extension meetings at the county and state level, and at regional and national scientific meetings.