Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/10/2008
Publication Date: N/A
Technical Abstract: Technical Abstract: Strict regulations limit the discharge of phosphorus from farmers’ fields in the Everglades Agricultural Area of Florida. University of Florida scientists have developed a robust set of best management practices (BMPs) that help farmers meet these regulations. Major principles of these best management practices are to encourage receding of shallow water tables more by evapotranspiration and less by discharging of water by pumping; and when pumping is necessary, discharge rates should remain as low as possible. The purpose of this presentation was to review applications to these BMPs of new information on sugarcane water tolerance. Response of sugarcane cultivars in Florida to shallow water-table depths commonly found in commercial fields varies from yield losses of 0 (CP 72-2086) to 25% (CP 80-1743). Presence of constitutive aerenchyma in sugarcane stalks is one trait that provides tolerance to shallow water-table depths. Cultivar responses to 4-day floods after planting also vary substantially; from essentially no emergence (CP 72-2086) to acceptable emergence (CP 89-2376). If fields are flooded before planted stalks are covered in the furrow, most cultivars can tolerate about 10 days of flood. Four cultivars had moderate yield increases when exposed to multiple cycles of 2-days flood followed by 12 days drainage; but one of two genotypes had substantial yield losses when exposed to multiple cycles of 7-days flood followed by 14 days drainage. Four cultivars had moderate increases when exposed to 10 or 20 day floods that were drained 3 weeks prior to harvest. A new hypothesis that is being tested is that sugarcane roots function adequately for up to 1 week while flooded, but sugarcane root growth is inhibited if the roots must grow into water beneath the soil. Sugarcane growers need to learn responses of their cultivars to shallow water-table depths and periodic flooding. The information presented about sugarcane water tolerance will better enable growers to comply with the BMP principles of reducing pump discharge amounts and rates.