If Florida sugar farmers stopped burning the cane fields before harvest, could they stay in business?

A class-action lawsuit was filed June 4, 2019, against Florida Crystals, Sugar Cane Growers Cooperative of Florida, United States Sugar Corporation, Flo-Sun Inc., American Sugar Refining Inc., Okeelanta Corp., Osceola Farms, Sugarland Harvesting, Trucane Sugar Corp., Independent Harvesting Inc., King Ranch Inc., J&J Ag Prodcuts Inc. and DOES 1-50, claiming that burning cane fields may be harmful to those who live in the area, and suggesting sugar farmers could switch from burnt cane harvesting to green cane harvesting.

However, research indicates the “green” method of harvesting sugar would mean lower crop yields for Florida farmers. Community leaders in the Glades worry such losses would mean the closing of sugar plants and the loss of jobs essential for the rural towns south of Lake Okeechobee. “I have seen the impact when you close down mills in this area and the economic impact it has on our community. We just can’t afford to lose the sugar industry,” said Pastor Robert L. Rease of St. John Missionary Baptist Church in Belle Glade at an Oct. 22 gathering in West Palm Beach.

The 2018 publication “Effects of Harvest Method on Microclimate in Florida Sugarcane” by Hardev Sandhu, Maninder Singh, Robert Gilbert, Kelly Morgan, Ronald Rice, Leslie Baucum, James Shine Jr. and Mike Irey, found green harvesting is more efficient in some places and burnt cane harvesting is more efficient in others. Much depends on the soil and climate of the area.

“The production systems for sugarcane (a complex hybrid of Saccharum spp.) include either green cane or burnt cane harvesting operations. In burnt cane harvesting, sugarcane fields are set on fire in order to burn off leafy material before harvesting in order to reduce transportation costs to the mill, improve harvesting efficiencies and enhance sugar recoveries at the mill. In green cane harvesting, sugarcane is harvested without burning, and a thick leafy residue (commonly called ‘trash blanket’ or trash) remains on the soil surface,” the researchers explained. That “trash blanket” may be beneficial for some soils as it adds nutrients back into the soil as it decays. But it can cause also cause problems.

The authors found differences in green harvesting vs. burnt harvesting in different types of soil. Green harvesting affects sugar cane grown in sand differently from the way it affects sugar cane grown in muck soil.

• In Brazil and South Africa, a study found green cane harvesting resulted in increases in sugarcane yield.
• In one study in Louisiana, green cane harvesting did not affect sugarcane yield. Another Louisiana study found burnt cane harvesting resulted in a greater yield than green cane harvesting.
• In Florida and Costa Rica, three-year average cane yield was greater following burnt-cane than green cane harvests.
• In Texas, switching from burnt cane to green cane harvesting saw a 20% yield reduction in the second ratoon.

(Ratooning is the agricultural practice of harvesting a crop by cutting most of the above-ground portion but leaving the roots and the growing shoots intact so as to allow the plants to recover and produce a fresh crop in the next season.)

“The amount of trash declined during the multi-year crop cycle, whereby plant cane had the greatest trash followed by progressively less trash for the first ratoon and second ratoon crops. As expected, green cane harvesting produced much more trash than burnt cane harvesting. The average amount of green cane trash on muck soil (7.7 tons/acre) was comparatively greater than sand (7.2 tons/acre), which is attributed to higher sugarcane yields on muck soils,” they explained.

The study found that leaving the “trash” on the ground had an effect on the soil temperature.

The researchers found that “air and soil temperatures are microclimatic factors, which control sugarcane emergence and growth. Young sugarcane plants can be very susceptible to freezes which highlight the importance of air temperature near the soil surface. It has been previously reported that soil capacity to absorb heat during daylight hours and then transfer this heat back to the air near the soil surface at night was greater in bare soil than for soils covered with mulch or crop residue.”