| [Image: barnyardgrass] |
| [Image: herbicideapplication] |
| [Image: post-atrazine-application] |
The LSU AgCenter is also conducting a sweet sorghum trial at the Rice Research Station South Farm location. The Rice Station sweet sorghum trial will focus on three major objectives: 1) to evaluate the fermentable sugar content differences of four varieties at a constant nitrogen (N) fertilization rate, 2) to evaluate the second (ratoon) crop potential of the four varieties and 3) to evaluate the ratoon crop response to various N fertilization rates. The varieties in the trial include Dale, M-81E, Topper 76-6 and Theis. Post harvest (ratoon) N application rates will include 0, 45, 90 and 135 lb N per acre, surface applied as urea.
The Rice Station trial was drill seeded to a conventionally tilled seedbed with adequate moisture on March 28. The sweet sorghum was planted at a rate of 1.5 pounds of seed per acre and to a depth of 0.25 inches. Row spacing was 30 inches. Emergence of the sweet sorghum was called on April 7.
Unfortunately, a flush of barnyard grass also emerged with the sweet sorghum, see Figure 1. To provide some control of the barnyard grass, atrazine (Atrazine 4L) was applied at a rate of 4 pints per acre with a 10-gallon-per-acre spray volume with using our 4-wheeler-mounted spray boom on April 11, as seen in Figure 2 below. In Figure 3, taken on April 17, you can see that the atrazine has slowed the growth of the barnyard grass, making it less competitive with the sweet sorghum. We will keep you informed of the progress of the sweet sorghum crop as the season progresses.
Dustin Harrell