Sugarcane postharvest residue management in a temperate climate
Full retention of sugarcane (interspecific hybrids of Saccharum spp.) postharvest residue may reduce ratoon crop yields. The objective of this study was to determine the effects of different residue removal timings and methods on sugarcane yield. A two-factor (timing and method) experiment was conducted on both clay and silt loam soils in southeastern Louisiana. Removal timings consisted of the following physiological stages: predormancy, complete dormancy, intermediate dormancy, and postdormancy. Removal methods consisted of partial removal from the row top by mechanical means, complete removal by burning, and no removal (control) applied to first, second, and third ratoons. Sugar yields following burning at predormancy (6800 kg ha–1), complete dormancy (6610 kg ha–1), and mechanical removal at predormancy (6500 kg ha–1) were greater than the control (6190 kg ha–1) for all ratoons. Burning at postdormancy decreased sugar yields by 440 kg ha–1 relative to the control. Ratoons responded similarly to the residue management practices evaluated, and effects were consistent on both clay and silt loam soils. Results show that the residue generated during the green-cane harvesting of sugarcane in Louisiana should be removed from harvested fields as soon after harvest as possible to ensure optimum yields of subsequent ratoon crops.