Sugarcane Responses to Water-Table Depth and Periodic Flood

Sugarcane (Saccharum spp.) is exposed to periodic floods and shallow water tables in Florida due to practices that reduce P discharge to the Everglades. This study examined the yields and juice quality of four sugarcane cultivars (CP 88-1762, Cl 89-2143, CP 89-2376, and CP 96-1252) maintained at constant water-table depths near 20 (20CWT) and 45 cm (45CWT) and with periodic summer flooding. Prescribed lysimeters were flooded for the first 7 d of five, five, and four 21-d cycles in 2005 (plant-cane crop), 2006 (first-ratoon crop), and 2007 (second-ratoon crop), respectively. These treatments generally remained flooded during the next 7 d while they received no irrigation or drainage, and were drained to 20 (20FWT) or 45 cm (45FWT) for the final 7 d of each cycle. Water treatment affected CRS only in the plant-cane crop, where 45CWT had lower CRS than 20CWT, 20FWT, and 45FWT. Yields of cane and sucrose of CP 89-2143 were least affected by water treatments. Reductions in cane and sucrose yields at a 20 compared with a 45 cm water-table depth were common for the other three cultivars, but yields under the 20CWT vs. 20FWT or 45CWT vs. 45FWT treatments were generally similar. These results suggest that sugarcane roots function well in flood for up to 14 d, but do not grow well into saturated soil. This provides new options for sustaining high yields of sugarcane exposed to shallow water tables and floods; verification of root responses could enhance strategies to sustain yields while reducing P discharge.