Developing Row Spacing and Planting Density Recommendations for Sweet Sorghum Production in the Southern Great Plains.

Sweet sorghum is gaining in popularity as an alternative source for a biofuel feedstock.  Its low nutrient and water requirement appears to fit well within the southern Great Plains arid climate.  The objectives of this project are to determine the optimum row spacing and plant population for sweet sorghum production in the southern Great Plains. Three locations in Oklahoma were established, ranging in precipitation from 820 mm to 920 mm. At each location two separate studies were conducted. To determine optimum plant population, plots were arranged in a randomized complete block design and seeded at rates of 70,000 seeds ha^-1 to 170,000 seeds ha^-1 in row spacing’s of 20 cm and 76 cm. To determine the effect of row spacing on sweet sorghum production two varieties were evaluated in spacing’s of 20 cm, 38 cm, and 76 cm. Plots were harvested at soft dough stage to obtain wet yield. Samples were pressed to determine juice extraction and brix values.  Optimum yields were obtained with a population of 170,000 plants ha^-1.  However, biomass yield of the 20 cm row spacing never reached a maximum.  Observations from row spacing studies indicated 20 and 38 cm rows were superior to 76 cm rows.  High population and narrow row spacing offers the maximum yield of biomass and juice extraction.