Louisiana soybean producers were able to plant an additional 6% of the crop during the week ending on June 7, 2020. The soybean crop in LA is now 94% planted with 87% emerged. Saturated soils and the threat of tropical storm Cristobal prevented some of the remaining 6% from being planted. A total of 31% of the crop has reached reproductive stages, 10% more than the 5-year average. A total of 1% of the crop is setting pods. The rating of the 2020 soybean crop continues to increase with 99% rated as fair-excellent. Furthermore, the excellent rating increased by 3%.

Figure 1. The Louisiana soybean planting progress has reached 94% complete as of June 7, 2020.

Figure 2. The rating of the 2020 soybean crop continues to increase with 99% rated as fair-excellent.

Soybean growth and development

On June 5, 2020, I recorded a video for a virtual field day at the Dean Lee Research Center. The main topic was the current development of a planting date trial. In the trial, I have maturity groups (MG) ranging from MG 3.6 to MG 5.4. For the field day, I focused on the development of a MG 4.5, 5.2, and 5.4 variety. The trial is designed to have six planting dates, ranging from March 19 to June 15. On June 5, five planting dates had been sown and the first three planting dates had varieties with growth stages ranging from vegetative (no reproductive structures) to beginning seed (R5 growth stage). Figure 3 shows how many days from planting each MG by planting date began blooming (R1 growth stage), the vegetative stage of the variety at R1, and the current growth stage (as of June 5). One thing I emphasized during the recording was the difference in growth and development between an indeterminate and semi-determinate variety. A soybean plant will be categorized as one of three growth habits: indeterminate, semi-determinate, and determinate. Indeterminate plants will begin flowering at an early vegetative stage and will continue increasing in the number of nodes on the main stem, while simultaneously producing reproductive structures. Determinate varieties will mostly cease vegetative growth at the onset of flowering, and semi-determinate plants will fall in the middle with a small increase of vegetative growth after the R1 growth stage. Figure 3 shows there were 35-39 days between planting and R1 for two indeterminate varieties (MG 4.5 and 5.2); and there were 58 days between planting and R1 for a semi-determinate variety (MG 5.4). In addition, the 4.5 and 5.2 varieties were between the V5-V6 growth stage at R1, where the MG 5.4 variety was between the V10-V11 growth stage.

Figure 3. Comparison of the growth and development of soybean plants of three different maturity groups and three planting dates.

Figure 4. An indeterminate maturity group 4.5 soybean plant that has reached the beginning seed growth stage (R5).

Figure 5. A semi-determinate maturity group 5.4 soybean plant that has reached the beginning pod growth stage (R3).