Rain during pod fill helped beans finish strong

If you had told the grower operating the Soybean Watch ’18 field in April that he would harvest about 60 bushels per acre, he would have been thrilled. It would turn out to be likely the second-highest soybean yield ever harvested on this field, going back more than four decades.

Reports from other areas indicate that some growers harvested higher yields in 2018, but others harvested lower yields. Reports in the eastern Corn Belt ranged from 40 to 90 bushels per acre for field averages. After years of the state’s average yield being stuck in the 40s to low 50s, it’s difficult to feel anything but satisfied with 60 bushels per acre, says Steve Gauck, who scouted the Soybean Watch ’18 field throughout the season. Still, different areas saw different challenges this year, he notes, and even individual fields within areas faced their own obstacles.

When the dust settled after harvest, it was clear that good production practices, strong genetics and ample rainfall during pod fill turned 2018 into a good year for soybean yields.

Gauck is a Beck’s sales agronomist based in Greensburg, Ind. Beck’s sponsors Soybean Watch ’18.

Early-season scouting
The Soybean Watch ’18 field was no-tilled in 15-inch rows with a planter in early May. Soils are primarily silt loams, with internal drainage issues. Part of the field slopes, with soils in one corner underlain with sand and gravel as two distinct landscapes merge. The field isn’t tiled or irrigated.

Emergence was good with one notable exception, Gauck recalls. “There were tracks where planting began,” he explains. “We determined they were caused by applying fertilizer with a buggy after planting.”

In that part of the field, crusting resulted in nearly zero stand over the tracks. Where fertilizer was applied before planting, tracks were evident later in the season, but emergence wasn’t affected.

The first big challenge came when heavy rains returned in early to mid-June. “The crop needed rain, but without drainage, some spots became saturated and started yellowing,” Gauck says.

By checking roots, he determined that nodulation was affected. Where water could move through the soil, plants were greener in color and nodulation was good. Bacteria within nodules on roots provide nitrogen.

Mid- and late-season notes
Soils dried out and the crop appeared in relatively good shape by midseason. “Weed control was good overall,” Gauck says. “We did find a few tall waterhemp plants and some mutant pigweed plants. There weren’t enough to bother this season, but signify that they could be an issue in the future.”

Until that discovery, the grower was unaware that tall waterhemp was on the farm.

Rains returned in August and pod development proceeded at a good pace. By mid-August, Gauck saw signs of sudden death syndrome. “There were scattered plants showing symptoms here,” he says. “We had more numerous calls and reports of SDS elsewhere. We saw quite a bit this year.”

The agronomist also saw several fields with stem canker, although not in this field. Green stinkbugs were prevalent in this field, however, and in many others. They may be one cause of quality issues that developed in some areas by harvest.

Soybean quality remained good overall in this field, according to the grower. Since the field was binned, exact yield isn’t known. Based on yield monitor information, the field averaged around 60 bushels per acre, with only minor differences among the three varieties. The grower termed yield difference among varieties as “not significant.”