Benefit To Soybean Farmers
Rye use for a cover crop prior to soybeans has become a trend being adopted in North Dakota. Rye makes up for a lot of weaknesses that soybeans bring to a cropping system. Some of the primary benefits include reducing soil erosion, increased weed control, additional grazing/forage material, utilization of excess soil moisture by rye allowing soybean to be planted timely, and allowing soybeans to be planted further into saline regions. The concept of this system is that winter rye is planted the fall before soybeans. The rye is terminated prior to or shortly after soybean planting. In the spring, prior to soybean planting, the rye is suppressing weeds, reducing wind and water erosion (after soybean planting too), and putting out roots and using water (in saline areas). Rye is best terminated with glyphosate.
Rye provides selective weed suppression, meaning that it is more effective against some species than others. Rye is particularly effective at suppressing kochia (up to 70% control in a heavy kochia infestation at CREC), and also does well against pigweed species, ragweed, and yellow foxtail. Rye has very little or no suppression of mint species (like lanceleaf sage), or most legumes. Thus, soybeans are not influenced by the presence of rye, except when moisture is limiting. In 2016 and 2017, when the springs have been very dry in Carrington, we’ve seen heavy injury to soybeans as a result of the limited rain. From 2013-2015 our results have shown rye to be very safe to soybeans, when there was more available moisture. This past research has led us to the finale of this current project which would seek to identify when soil moisture drops to a level that creates risk to soybeans from the rye. The research leaders involved with this project have had past experience and training in monitoring soil water use and moisture status with other projects.
Many producers are beginning to see the advantages of using rye prior to soybeans. However as mentioned, this system comes with risks. As more people adopt this system there are more opportunities for things to go wrong (particularly as people get familiar with managing a new system). By accomplishing the stated goals of this study, we would provide the information needed to minimize risk to soybean producers. In 2016, the moisture deficit was so severe in Carrington that the only time rye was safe with soybeans was when it was terminated early in the spring. I haven’t been made aware of any crop failures from rye as of yet, but the potential is there. The key to avoiding that scenario is to manage the risk factors.