Optimizing Planting and Harvesting Dates of Energybeet Varieties Grown for Bioenergy in South Florida.

Sugar feedstocks such as energybeet (Beta vulgaris) are easy to convert and efficient for bioenergy production. Management practices including planting and harvest date and pest management can affect total biomass production and sugar yield, but relatively few data are available for energybeet grown in the southeastern USA. Therefore, a study was conducted at Belle Glade, FL on organic soil comparing the effect of planting and harvest dates on biomass and sugar yield of energybeet varieties during 2013. Three energybeet varieties were planted at three times (October, November, and December) and harvested at four times (March, April, May, and June), both under pesticide sprayed and non-sprayed conditions with four replications per treatment. October planting resulted in 17 and 59% increase in root yield and 17 and 68% increase in sugar yield compared to November and December planting, respectively. Delay in harvest from March to June resulted in increase in root fraction and decrease in leaf fraction. Root yield increased with delay in harvesting until June, however juice brix declined late in season resulting in greatest sugar yield in May (8.4 Mg ha^-1). Energybeet varieties used in this study did not differ in total sugar yield. Pesticide application resulted in significant root and sugar yield increase only under early planting (October-November) and late harvest (May-June). Overall, root and sugar yield of 70-80 and 7.5-8.5 Mg ha^-1 respectively were observed under early planting and late harvest in this study. Results indicated that energybeet can be grown as a rotational crop with sugarcane to produce high sugar yield on organic soil in south Florida.