8/16/2014 7:00 AM
By Michael Short Delmarva Correspondent
GEORGETOWN, Del. — Even though torrential rains forced changes to Tuesday’s soybean Diagnostic Day, the day was still well-received, according to organizers.
The Delaware Soybean Board’s Diagnostic Day drew around 40 farmers from the area. This year’s program was held at the University of Delaware’s Carvel Research and Education Center just west of Georgetown. Farmers listened to university experts talk about weeds, herbicides, pest problems and the life cycle of the soybean.
A downpour forced organizers to change plans. Farmers were forced inside and under tents instead of using sweep nets to capture pests or spending the afternoon in fields to see the impact of herbicide timing.
The event was designed to help growers feel more comfortable diagnosing soybean production problems. The event was a joint effort of the Delaware Soybean Board, United Soybean Board and the University of Delaware.
Susanne Zilberfarb of the Delaware Soybean Board, explained that the organization holds an event each year to help sharpen the skills of farmers. She said the board tries “something new and different and educational,” she said.
Tuesday’s session helped farmers identify pests and how and when to spray pesticides or herbicides. It also touched on the topic of whether or not to apply nitrogen to soybean crops.
Soybeans are able to fix nitrogen and farmers don’t usually add any additional nitrogen. But in some cases, farmers may want to reconsider that idea.
University nutrient specialist Amy Shober said that adding nitrogen in high-yield situations may be worth considering. She said that for yields below 60 bushels per acre, it’s probably not beneficial. But nitrogen, in amounts of less than 45 pounds per acre, could help farmers in high-yield situations.
“The research is really mixed,” she said.
Adding too much nitrogen can actually reduce yields, so it’s a delicate balance, and the university does not recommend adding more than 30 pounds per acre. For dry-land soybeans, Shober said water is probably the limiting factor, not nitrogen. If the beans have cyst nematodes, then that’s probably the limiting factor, not nitrogen.
Farmers were told manganese deficiency is the most common micronutrient deficiency for soybeans. If additional manganese is added, speakers at the event said it should be applied before soybeans reach the reproductive stage.
Farmers were urged to add manganese with caution because even small amounts of manganese can be potentially toxic. Because of that, Shober said farmers should make sure there really is a problem before applying any extra manganese.
She said a manganese deficiency can mimic several other soybean issues such as pesticide drift problems, making testing a necessity.
Shober also told farmers that university recommendations for potassium levels may be low and are currently being looked at. Her suggestion was to monitor potassium levels, especially if soybeans are double-cropped and grown on irrigated soils. Irrigation can potentially leach out potassium, she said.