Large areas of the soybean belt have poor quality soybeans that are being either severely discounted or outright refused at the elevator. In Kansas, there are confirmed reports of loads being rejected at local elevators and large terminals due to high levels of purple seed stain (Figure 1). One reason for these rejections could be due to a reduction in feed value.
Figure 1. Purple seed stain on soybeans (Photo by Michael Tokach, K-State Research and Extension).
What led to the reduction in quality?
When seeking a cause, look no further than the constant rain during the crop’s reproductive period. According to Kansas Mesonet records, many areas in northeast and east central Kansas received between 5 to 16 inches of rain between August 7 and September 7. Rain during these parts of the reproductive growth stages provides an ideal climate for infection by seed and stem pathogens including pod and stem blight, purple seed stain, and anthracnose. Following this initial infection period, further significant rainfall in the early part of October allowed these diseases to progress. Collectively, they are responsible for the shrunken, discolored, poor quality beans. Besides the poorer quality, these diseases can cause empty pods or pods with seeds so small they are left in the field because they are too light to make it past the fans, resulting in direct yield loss.
Options for feeding damaged soybeans
Rather than taking a significant dockage or even a rejection at the elevator, producers have the option to use these soybeans as a feed source for animals, particularly cattle. Given their protein value, soybeans are a good source of protein for cows and can be used in developing heifers. However, given the fat content in soybeans, damaged soybeans can become rancid. This is less of an issue in colder weather. Aside from younger calves, it is recommended to limit inclusion of these beans to no more than 10-15% dry matter in a ration. If possible, its preferred to slightly roll them as they are being used. Mature cows could be allowed up to 4 pounds before fat levels and ruminal fiber digestion is a concern. For pigs, the soybeans would need to be roasted or extruded prior to feeding to destroy the urease activity.
Considerations for grain storage
For producers seeking to store their beans rather than take the elevator discount, they should keep in mind that the quality of grain coming out of a bin will never be better than when it went in. Therefore, the main storage goal is to keep it from further deteriorating. Since bean mold and discoloration is caused by actively growing fungi, the aim is to slow or stop further growth in the bin. This is best done by controlling grain moisture, temperature, and relative humidity in the bin. For longer-term storage, grain moisture needs to be below 15% moisture, but 12 – 13% would be even better. Cool the grain to below 50 degrees F as quickly as possible. Initially, when weather is still warm, this is difficult to do. It is best to run bin fans at night when temperatures are cooler and then shut them off during the day as it warms. Eventually, you will be able to reach the 50-degree mark, but of course, cooler is better. As the grain dries, relative humidity levels should also decrease. These storage conditions will be sufficient for short-term storage over the winter.
Regularly monitor storage bins. Check for leaks in the structure and be on the lookout for condensation in the headspace. If condensed water drips on the grain surface, fungi may resume growing and this may lead to surface crusting. Inspect bins for sour, musty, earthy, or putrid odors. These odors indicate a fungal problem — most likely due to high grain moisture from improper drying, leaks, or insect activity. If the grain gets wet, use a fan to increase airflow and reduce grain moisture — this can halt fungal growth.
Before filling any grain bin, be sure to clean it by removing all grain from the floor and walls. Thorough cleaning will help remove any grain carryover from the previous crop that may increase the chances of additional contamination. Some of this information has been adapted from Storing Mycotoxin Affected Grain, Bulletin CPN-2004, https://cropprotectionnetwork.org
Other options
For producers that do not wish to feed or store these beans, they can blend affected loads with clean soybeans to reduce the dockage and reach an acceptable threshold. Some growers may not harvest some of their soybean fields this season. Grazing these fields is an option. It is important to supplement with an additional forage source, such as hay or corn residue, as soybean plants have little nutritional value. Also, cattle may select full bean pods and can scour if they consume too much. Avoid over consumption of soybeans by providing limited access to these fields and/or having hay or another feed as an alternative.
Remember, do not provide access to any supplements that contain urea when allowing cattle to consume raw soybeans.
For more information on using soybeans as cattle feed, please see an article from University of Nebraska’s CropWatch: Can Damaged or Discolored Soybeans be used as Cattle Feed? at: https://cropwatch.unl.edu/2018/soybeans-as-cattle-feed
Stu Duncan, Northeast Area Crops and Soils Specialist
sduncan@ksu.edu
Doug Jardine, Extension Plant Pathologist
jardine@ksu.edu
Dale Blasi, Extension Beef Cattle Specialist
dblasi@ksu.edu
Michael Tokach, University Distinguished Professor, Extension Swine Specialist
mtokach@ksu.edu
Ignacio Ciampitti, Crop Production and Cropping Systems Specialist
ciampitti@ksu.edu