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

Abstract

Sweet sorghum is gaining in popularity as an alternative biofuel feedstock. Its potential for low nutrient and water requirement appears to fit well within the southern Great Plains arid climate. The objectives of this project were 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 to 1,070 mm west to east, respectively. At each location two separate studies were conducted: row spacing and planting density. To determine the effect of row spacing on sweet sorghum production two varieties, Topper and M81, were evaluated in spacings of 20, 38, and 76 cm. To determine optimum plant density, plots were arranged in a randomized complete block design and seeded at rates of 74,100 to 172,900 seeds ha-1 in 20 and 76-cm row spacings using one cultivar, M81. Plots were harvested at soft dough stage to obtain wet yield. Samples were pressed to determine juice extraction and brix values. Observations from row spacing studies indicated 20 and 38-cm rows were superior to 76-cm rows. 175,000 to 250,000 plants ha-1 and narrow row spacing offers the maximum yield of biomass and juice extraction.