Shaun Casteel thought it was time to look at the concept of applying starter fertilizer on soybeans again. It has been examined before, but no one has ever proven a consistent yield response for doing it. With the drive for top yields, he's giving it another look.
Some of the plots with starter fertilizer are located at the Southeast Purdue Ag Center near Butlerville in Jennings County.
"Notice how this set of rows are somewhat greener and a bit taller," he told an audience at a recent field day. "Starter fertilizer was applied on that plot." The same trial also compares planting dates and soybean populations.
Casteel explains that based on past testing, the soybeans may be bigger or greener mid-season. But they may not yield more in the end.
If something isn't significantly better, there is more probability than scientists like that the increase seen for the treatment, if any, is due to experimental error.
Someone asked Casteel that if there was ever going to be a response, could it be this year? He turned the question back into a question for the audience. After fielding comments, he noted that yes, if there was ever going to be a response it might be in 2014, at least in the SEPAC plots.
Why? Because soybeans were slow to take off in some areas. Several factors went against plants early. Soybeans should look awkward and slightly yellow at the V3, or two trifoliates emerged stage, he says. That's because the nodules haven't kicked in producing nitrogen for the plant yet. But this year some plants still looked that way by V6. Some fields were so extreme in a slow take-off that he actually recommended adding 40 to 60 units of nitrogen as urea to kick-start growth in the field.
At that level, the nodules won't be impacted. Instead, they will eventually more likely take off and do their job, and the plants will grow again.
If starter fertilizer helps avoid that occurrence, then it's possible that a yield advantage might, emphasize might, show up.