David Moseley, LSU AgCenter soybean specialist

Article Highlights:

• It is important for a producer to consider how varieties perform in an environment similar to their own and in multiple environments.
• The LSU AgCenter conducts an Official Variety Trial (OVT) and Core-block demonstration plots to provide unbiased data to assist in variety selection.
• The LSU AgCenter also conducted other on-farm demonstrations including variety evaluations (conventional and nematode resistance) and fertilizer applications (potassium and manganese).

Selecting the most adapted and high yielding varieties is one of the most important decisions a soybean producer makes every year. The LSU AgCenter conducts an Official Variety Trial (OVT) and Core-block demonstration plots to provide unbiased data to assist in variety selection. The OVT and core-block demonstrations are planted throughout the state to collect performance data in different environments. It is important for a producer to consider how varieties perform in an environment similar to their own and in multiple environments. Varieties that perform consistently well across multiple environments and years could be considered to have more performance stability.

Official Variety Trial

The 2023 OVT includes varieties with maturity groups ranging from 3.7 – 5.8. The maturity groups are divided into sections including 3.7-4.4; 4.5-4.7; 4.8-4.9; 5.0-5.3; and 5.4-5.8, and there were 12; 22, 15; 10; and 12 varieties submitted to the maturity group sections, respectively, by nine seed companies and one soybean breeding program. The varieties consist of several different herbicide technologies. The trial is replicated at seven research stations across the state in different soil types including fine sandy loam, silt loam, silty clay, and clay. At each location, the varieties are replicated four times.

On-farm Core-block Demonstration Plots

In addition to the OVT, the LSU AgCenter collaborates with soybean producers to evaluate soybean varieties directly on farms. For the core-block demonstration program, the LSU AgCenter parish agents cooperate with producers to plant, maintain, and harvest strip trials submitted by seed companies and university soybean breeding programs. These demonstrations provide valuable yield data from local growing conditions and agronomic practices.

In 2023, seven seed companies submitted varieties to be evaluated in the core-block demonstrations. Twenty-seven demonstrations were planted across 14 parishes. The demonstrations were divided by maturity group (MG). A demonstration consisted of varieties with a MG of 3.9 to 4.4; 4.5 to 4.9; or 5.0 to 5.8. The number of varieties submitted for each MG were five (MG 3.7 to 4.4), twelve (MG 4.5 to 4.9) and eight (MG 5.0 to 5.6).

Nematode resistance demonstrations were conducted again in 2023. A total of seven varieties from four seed companies were entered into the nematode resistance screening trial. Among the varieties, six were entered as resistant varieties and one was entered as a susceptible variety. The nematode resistant demonstrations were planted in three parishes (Tensas, Franklin, and Bossier) in fields known to have nematode pressure. Along with yield, nematode assays were taken near the R8 (mature) growth stage. To complement this trial, Dr. Tristan Watson (LSU AgCenter Nematologist) also conducted greenhouse trials to determine the level of resistance for each variety.

Conventional soybean variety demonstrations were conducted in Acadia, Bossier, Franklin, and Tensas parishes. The University of Missouri and a seed company entered a total of seven conventional varieties. For comparison, a glyphosate and dicamba commercial check was included in the demonstrations. Data from these demonstrations will help farmers who produce soybean in herbicide restricted habitats and who are looking for a potential premium from conventional soybean varieties.

In addition to the variety trials, a potassium demonstration was conducted in Beauregard parish on a light soil with very low potassium soil levels. Granular and foliar applications of potassium were applied at various times and rates (eight different applications). This data will help farmers understand best management practices to economically correct low potassium levels.

In 2023, an on-farm manganese trial was initiated in Catahoula parish. The trial was initiated in two fields covering a total of approximately 170 acres. There were 13 different treatments with different fertilizer formulations, rates, and timing applied. In addition to manganese, the treatments included different fertilizers to help alleviate other nutrient deficiencies. Follow-up trials on the farm will be to examine different fertilizer rates and application timings for a better understanding of the most economical fertilizer program for those fields.

The parishes in which the soybean core-block demonstrations were located in 2023 are indicated in figure 1.

Variety Testing and On-farm Core-block Demonstration Results

The performance data from the soybean OVT and on-farm core-block demonstrations will be published by the LSU AgCenter in the annual soybean variety testing summary. Maturity date, height, lodging and disease reaction information from the OVT will also be included. The 2023 OVT results will be published following harvest to assist with 2024 variety selections and planting decisions. The variety publication for the 2022 growing season can be found at 2023 Soybean Variety Yields and Production Practices

More information on LSU AgCenter variety testing can be found in the Louisiana Agriculture Magazine Vol. 64, No. 1, Winter 2021.

Figure 1: 2023 soybean core-block locations