Smart-Till: A Potential Solution to SDS

Drainage is one of the best ways to combat SDS

Dr. Daniel Davidson, Agronomist

Sudden Death Syndrome (SDS) is an increasing problem for soybean producers and it seems to be partly associated with the wet springs growers having been experiencing in the last few years. Scott Hon, a producer from Crossville, Illinois, believes that the Smart-Till is helping alleviate the SDS problem in his soybeans. Hon says he bought into vertical tillage after years of deep-ripping his soils in southeastern Illinois along the Little Wabash River.

Hon commented that as growers are getting bigger they are switching to all no-till and cannot spend as much time managing individual fields which he still tries to do. After running aeration tools for a number of years he noticed that he needed to rip less, soils warmed up more quickly in the spring and he is able to get in the field 5 to 7 days sooner. He calls his Smart-Till his starter because he gets the same benefit to corn growth that his neighbors get from using a starter yet he gets to plant sooner.

He added that his soils are tight clays, heavy blacks or gumbo and lack drainage and routinely result in cool and wet soils. "We work at managing compaction," said Hon. "We tippy toe around to keep our fields in good shape and prevent compaction and realized we needed a tool to get more aeration."

"No tillers in my area are seeing more SDS in their fields and I just don't see it in my field," said Hon "We have noticed that when running an aeration tool the soils dry and warm faster and that seems to have an effect." Hon has zeroed in on one of the conditions that contributes to SDS, wet and cool soils in the spring. The other is the presence of the disease in the field. And since he hasn't seen the disease in his fields and he works to keep his soils dry and aerated in the spring, he has lessened his chances of the disease getting a foothold.

SDS is a fungal disease that infects plants in the spring but doesn't show up until mid-summer. The soil-borne fungus infects roots early in the season but symptoms are not evident until later. As growth continues, root rot symptoms develop and the fungus produces a toxin that is translocated to the foliage leading to death. SDS development favors cool and moist conditions in the spring and warm and humid conditions during the summer. Leaves begin to cup and turn necrotic. It may start with a single plant or circular areas of the plant. Eventually plants will defoliate and die and seeds will be small. Historically the disease was most prevalent in headlands, compacted areas and wet depressional areas.

So how can the Smart-Till help alleviate SDS? Remember the pathogen infects seedling roots during wet springs when root rots are more common place and anything you can do to drain the dry the soil should help reduce the risk of SDS infections. The Smart-Till tine design along with the rolling harrow is intended to process and fluff up crop residue which can help the soil surface dry faster. In addition, the tine operation, running to a depth of 8 inches will break compaction and improve drainage and aeration and drying. The end result is a moist, but not overly wet soil profile that resists SDS infection.

SDS management recommendation includes planting resistant or partially resistant varieties, reducing excessive soil moisture with drainage, minimizing soil compaction from excessive trafficking when wet, and planting fields with a history of SDS last; reducing exposure to cool, wet conditions early in the season that fosters SDS infection.

Aeration tools like the Smart-Till are another tool to help combat the threat of an SDS outbreak.