Scouting fields aerially, either with an unmanned aerial vehicle or through satellite imagery, was worth its weight in gold this year. If you’re not convinced, take a close look at the picture taken by a drone flying over the Soybean Watch ’19 field in mid-August.
There are several strips of greener soybeans running at an angle from the middle of the picture. In between are lighter patches where perhaps the canopy isn’t fully closed yet. Because the strips don’t go all the way across the field, and the field was no-tilled at an angle to the strips, not tilled, Steve Gauck ruled out soil compaction or any tillage effect as the cause.
Gauck, a Beck’s sales agronomist based near Greensburg, Ind., was the remote pilot flying the drone. Beck’s sponsors Soybean Watch ’19.
“It became pretty clear that the darker strips were soybeans growing over tile lines,” Gauck says. “The areas in between didn’t get the full effect of drainage.”
So why were the strips over tile lines showing up as greener, darker spots. Erma Bombeck wrote a book called “It’s Always Greener Over the Septic Tank.” These are tile lines, not runs from a septic tank, so it wasn’t extra nitrogen seeping out and causing the change in color in the plants.
“I believe it goes back to when the crop was planted,” Gauck says. The field was planted June 12. Rains set in June 15, with the field receiving around 5 inches of rain over the next 10 days.
“Areas over the tile line handled water better or dried out faster, and more soybeans germinated and survived compared to areas in between the tile lines,” he explains. “What we see in that picture is that by mid-August, areas over the tile lines had filled the canopy between the 15-inch rows, like most of the rest of the field. The soybean stand was thinner in the middles between lines, where soils remained too wet for good germination, emergence and survival of young seedlings. So, we’re seeing a difference in stand caused by wet weather in late June. For this field this year, that was the key time for germination, emergence and stand establishment.”
Picking up a pattern like that one in August may be unusual. It might seem more logical that perhaps it was a long dry spell, and soybeans over the tile lines were picking up moisture from the tiling. But that wasn’t the case in this field this year.
“It’s just been an unusual year from the beginning,” Gauck says. “If that field had been planted June 14, two days later, the entire field may have experienced more stand establishment issues because of saturated soils. Maybe soybean fields in that area planted June 14 were replanted once it dried out again.
“If this year proves anything, it reinforces the idea that timing is everything, and that adequate tile drainage at key times, especially when you’re planting and the crop is trying to establish itself, is crucial.”