Source: Ohio State University Extension
At several meetings and based on a few emails this winter, it is very clear that soybean farmers are examining their budgets and looking for ways to cut costs in 2015. Planting "naked" seed — no fungicide seed treatment — is one place that some growers are contemplating.
There is plenty of concern if this is really a good choice to reduce costs. It is true that soybeans do not always need a fungicide seed treatment. However, on soils with poor drainage where replanting is relatively common, replanting costs today are much higher than our estimates of $80 per acre from 10 years ago. Basically, seed treatments are an insurance policy to protect that young seed/seedling until it is out of the ground and growing.
Here are some reasons to consider using seed treatments:
1. Farm has a history of replanting. No question — use fungicide seed treatments. Even at the older estimates of replanting associated costs, one replant will pay for more than 10 years of a seed treatment.
2. Farm drainage system has not been updated or field is slow to drain after heavy rains. More often than not, seed treatments will protect and have added yield benefits compared to non-treated seed. All of the soil-borne pathogens that can infect soybean require high moisture. With a properly designed, well-maintained drainage system, the amount of time a field is saturated is greatly reduced. If the system is poor, old or not functioning well, the time the field is saturated is much longer, which amounts to more seeds/seedlings becoming infected when those heavy rains occur.
3. Reduce seeding rates in 2015. This is another place where seed treatments are beginning to play a larger role. With reduced seeding rates, every seed becomes important and seed treatments can have a large contribution to maintaining early plant populations. In some of our seed treatment studies, the treated seed is emerging at greater than 90% of the seed we planted compared to non-treated seed, which may be less than 50%.
4. Fields with numerous pathotypes of Phytophthora sojae that causes early season damping-off. We have shown over a number of studies that if a grower is totally dependent on the partial resistance portion of the resistance package, seed treatments are needed to protect the plants until they are up and out of the ground.
5. Early planting and very cool temperatures. The cooler the spring, the longer the seed/seedling will sit belowground, giving these soil-borne pathogens more time to feed. For those first fields, seed treatments can provide the protection, especially when it takes 2-3 weeks for them to emerge.
There are some field conditions when a seed treatment is not needed, and they're are also the conditions needed for no seed treatments so a grower doesn't pay a penalty (replant) down the road.
1. Planting into warm, well-drained soil. Those perfect planting conditions when the seed will probably emerge 2-3 days after planting. Or it feels like that.
2. No heavy rains are predicted for the region for the 2 weeks following planting.