Results from Kansas State University seed treatment trials (2004-2012) on soybeans at planting found an average yield increase of 2.5 bushels per acre when a seed treatment was routinely used. According to Dr. Doug Jardine, K-State Plant Pathologist, these results demonstrate that soybean planting time seed treatments are a very reliable way to “protect” yields.
How do I know if I should treat my soybeans?
Fields that are poorly drained or no-tilled fields, continuous-soybean or soybean-corn rotations and a history of replanting are the most likely to see the added benefit of using a seed treatment. – The Ohio State University
Cool and wet spring conditions. – University of Wisconsin-Madison
Fields with a propensity towards soil crusting, temporary flooding, or compaction. – University of Kentucky
Treatments are also useful when farmers use low seeding rates and when farmers’ plant seed with a moderate germination rate or when the germination rate is unknown. – University of Kentucky
Using a fungicide treatment on soybean seeds will increase the probability of achieving a satisfactory stand and will enhance the early-season vigor of established seedlings. – Mississippi Soybean Promotion Board
Do I need inoculant?
Inoculant is highly recommended for fields that have either never been planted to soybeans or have been out of soybean production for more than several years. Soybeans use high levels of nitrogen, removing approximately 3-4 pounds of nitrogen per bushel of seed produced. If soybeans are poorly nodulated, then they will have to take up most of their needed nitrogen from the soil.
It is important to note that neither soybeans nor the Bradyrhizobium japonicum bacteria strain are native to the United States, so there will be no Bradyrhizobium japonicum in the soil unless it was introduced at some time in the past on inoculated soybean seed. This species of bacteria is responsible for nodulation and will help the soybean plant produce somewhere between 40-80 percent of the soybeans plant’s nitrogen needs for the year.
Do I need inoculant if I am on a corn-soybean rotation?
Your field should have some remaining bacteria population from previous years, however one must remember that bacteria are live organisms so many of Mother Nature’s forces can have negative effects on their population in the soil. Fields that have experienced severe drought or flooding will have significantly lower bacteria populations. Other environmental factors that can reduce bacteria population in your soil include low organic matter and extreme pH levels. The short answer to this question; soybean inoculation is a good insurance policy for your field if you are worried about the bacteria population levels.