Barry Glaz and Dolen R. Morris. USDA-ARS-SAA, 12990 U.S. Highway 441 N, Canal Point, FL 33438
Sugarcane (Saccharum spp.) in the Everglades Agricultural Area (EAA) of Florida is often exposed to high water tables and periodic floods. Growers are concerned that elevated water tables for prolonged periods and during certain phases of growth reduce yields. However, these wet conditions help conserve the organic soils of the EAA and help reduce unwanted phosphorus discharge to natural areas of the Everglades near the EAA. The purpose of this presentation is to review research on the effects of high water tables on sugarcane yields, to identify morphological and physiological mechanisms of sugarcane that improve its water tolerance, and to identify and develop agronomic practices to improve sugarcane yields under elevated water tables. In a field study of nine sugarcane cultivars exposed to target water-table depths of 15 and 38 cm, ‘CP 80-1743’ had yield losses of 25% at the 15-cm depth, but ‘CP 72-2086’ had similar yields at both depths. A lysimeter study with two sugarcane genotypes indicated that the presence of constitutive aerenchyma in sugarcane stalks provided tolerance to water-table depths as shallow as 16 cm and to repeated 7-day periodic floods. Although monitoring leaf photosynthesis has not been useful, high tiller number combined with large stalk diameter may be useful traits for identifying water tolerance among sugarcane genotypes. Yields were improved for two sugarcane cultivars by repeated 2-day periodic floods in the plant-cane and first-ratoon crops. Genotype responses to 6-day floods applied at planting ranged from no emergence reductions to lack of emergence. Current sugarcane yield losses due to elevated commercial water tables vary from none to substantial and are influenced by duration and timing of wet conditions and cultivar.