Sweet Sorghum (for Ethanol) Harvesting Trials in Florida Using John Deere 3520 Cane Harvester

As much of the U.S. digs out from freezing weather and snowstorms, Florida's extended growing season allows Farmers to still be growing and harvesting crops like sweet sorghum for ethanol feedstock. A late fall/early winter crop rotation for sorghum takes a little longer to mature (approximately 105 to 110 days from planting) compared to warmer months (where plant maturity occurs in ~90 days) -- due to the reduced amount of daylight hours. Also, while the sorghum's brix (sugar content) appears to be consistent at ~18 throughout all yearly rotations, yields during the fall/winter rotation can be ~40% less than warm weather months primarily because of reduced rainfall (as we do not field irrigate our sorghum). Ratoon yields of our sorghum is extremely poor, as we are using commercial hybrids.

Because of this extended growing season, it is believed that the typical agriculture plan for growing sweet sorghum can be three (3) crop rotations per year on the same acreage (allowing for cyclical soil resting/building to reduce plant disease/pests by rotating in crops like soil nitrogen building white clover legumes).

In early December we conducted sweet sorghum harvesting trials using the newly developed John Deere 3520 cane harvester (developed primarily for the sugar cane industry in South Florida, Louisiana, and Brazil). The capital cost of the Deere 3520 is ~$310,000 with the ability to harvest between 8 and 10 acres per hour (or around +100 acres per day).

The first two pictures below show the Deere 3520 and its total 9 foot width, and 3 foot cutting area dimensions:





The next two pictures shows the sorghum product of the Deere 3520 Harvester -- a 4 to 6 inch billet which is blown into a trailing hay wagon.





The Deere 3520 provides for flexibility in field row planting configurations (18, 24, 36 inch centers) allowing for single pass, two row and even 3 row cutting. The below schematic illustrates the row planting configuration that we use.