Soybean Seed Quality Issues for Spring 2008
It’s no secret that soybean seed quality across the industry is coming in below average this year. Hot and dry conditions during 2007 harvest resulted in thin, fragile seed coats. Handling beans with weakened seed coats leads to a high degree of mechanical damage (cracking and breaking) resulting in low germination percentages. In fact, the more the beans are handled, the lower the percent germs are coming back from the seed lab. This is the reason many companies have opted not to treat their bean varieties this year due to the extra handling step involved and the potential for lower germs.
So what’s a farmer to do? The first step is to check the seed tag for the germination percentage and adjust your seeding rate accordingly (more on that subject later). Handle the beans with extra care. Don’t drop bags while tossing them here and there. If possible use belt conveyors rather than metal augers when moving seed. Delay planting until the soil is dry and soil temperatures are above 55-60º degrees. In short, do everything possible to eliminate stresses and maximize emergence.
If you receive some low % germ soybeans and anticipate that stands will be less than desirable, then don’t lock yourself into planting soybeans by applying a preplant soybean herbicide such as Canopy, Scepter, FirstRate, Classic, Extreme, etc. Keep your options open in the advent that replanting to corn would be a better management decision.
One advantage soybeans have over corn is their ability to compensate for missing plants by developing branches. This characteristic will come in handy this year as low germ beans will no doubt produce gaps in the row. The more branches, the more nodes per plant, and the more nodes means more places for pods to form and seed to develop. So if soybeans can compensate for thin stands, what is the lowest plant population that will produce a “normal” yield? Midwest university agronomists* all agree that a uniform, final plant stand of 100,000 is sufficient to produce an adequate crop. Use the table below to estimate the final plant stand based on the percent germs from your seed tags and your target seeding rate.
**Purdue University, Shawn Conley; University of Illinois, Emerson Nafziger; Iowa State University, Palle Pedersen
Have a good weekend!
Dan Childs, Agronomist
