Matt Foster, doctoral student, left, and Al Orgeron, LSU AgCenter pest management specialist, inspect soybeans at the Sugar Research Station near St. Gabriel. Photo by Bruce Schultz

Al Orgeron, LSU AgCenter pest management specialist, and doctoral student Matt Foster have a series of studies at the Sugar Research Station near St. Gabriel aimed at helping sugarcane farmers who use soybeans as a rotational crop.

Cane farmers are eager to get their land planted to cane by late summer, so they want to get their fallow season of beans harvested as soon as possible, Orgeron said. “Typically, cane farmers plant earlier so they can plant cane in August.”

He said some farmers have had difficulty harvesting good yields with early planting of late-Group III and Group IV beans.

In their study, Foster and Orgeron planted Maturity Group 4.2 through 4.8 soybeans in four different plantings, starting on March 23, followed by April 6, April 19 and May 6. By mid-May, the earliest planted beans were in the R-2 stage, and plants in the second planting date had reached R-1.

“We’re just trying to push that planting window and not compromise yield,” Orgeron said.

The targeted harvest is the first week of August.

The test plots were planted in twin rows, 18 inches apart into a stale cane bed at the rate of 120,000 seedlings per acre, with 100,000 per acre actually emerging.

By planting earlier, the crop is more likely to develop ahead of the hottest weather during most years, Orgeron said. Also, a soybean crop that develops a full canopy earlier provides less sunlight for weed growth, he said.

Seed treatments tested

In another project, nine combinations of fungicide and insecticide seed treatments are being tested to determine if the extra expense can be justified through increased yields.

They also have a test evaluating no-till beans into the last stubble of a sugarcane crop, using different herbicides to control weeds.

“Purple nutsedge is becoming a bigger problem for cane growers,” Orgeron said. “Glyphosate alone is not taking it out.”

Orgeron said the study is evaluating Authority XL, Spartan and Permit Plus as potential pre-emerge treatments in combination with glyphosate.

Orgeron said another study is looking at the use of the product Bio-Forage ST as a seed treatment that could help soybeans better manage stresses such as drought.

Southwest Louisiana soybeans

Research is being done for southwest Louisiana soybean farmers by Dustin Harrell, LSU AgCenter agronomist. He said his soybean work includes a date-of-planting study at the South Farm of the H. Rouse Caffey Rice Research Station. Planting was done on six different days starting April 4, with the last on June 20. Because of weather conditions, no March planting could be done, Harrell said. But overall weather conditions have been much better than the 2015 growing season.

Near Mamou, a nutrient study is testing different rates of potassium, phosphorus and zinc, and an application test is being done for potassium and phosphorus at different growth stages, starting at planting and continuing through R-6 (full pod).

“We should have some good data coming out of this project,” Harrell said.

Bruce Schultz