The sweet sorghum varieties Dale, M81-E, Theis and Topper were planted in a variety trial at the Hill Farm Research Station on April 16, 2008. Since this is not a row crop area and has high soil erosion potential, plantings were made as close-spaced drill plantings similar to procedures used for annual forage crops such as forage sorghums and small grains. High plant populations, which contribute to smaller stems and increased quality of forage crops, are not necessarily appropriate for sweet sorghum used as an energy crop. Therefore, two seeding rates (2 and 10 pounds per acre) also were evaluated.
Emergence of all entries was quick, but it was followed a few days later by a very light and non-uniform frost, which thinned populations in some plots. Sufficient stands remained to accomplish objectives, and plants grew vigorously. After three weeks with essentially no rainfall, plants were expressing moisture stress as shown in the accompanying photo (No. 1) taken on June 6. Rain early the following week alleviated at least some of the moisture-stress symptoms as shown by return of leaves to upright positions in photo No. 2 taken on June 12.
Plant counts taken on June 9 resulted in an average overall plant population of 1.9 plants per square foot with distinct differences among plots associated with both the original seeding rate and minor variations in topography (due to frost effects).
[Image: Hill Farm Sweet Sorghum test 1]
| [Image: Hill Farm Sweet Sorghum Test 2]
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