|Daroub, Samira - UNIVERSITY OF FLORIDA|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 22, 2003
Publication Date: May 1, 2004
Citation: Glaz, B.S., Morris, D.R., Daroub, S. 2004. Periodic flood and water table effects on two sugarcane genotypes. Agronomy Journal. 96:832-838 Interpretive Summary: Sugarcane, the primary crop on the organic soils of the Everglades Agricultural Area in Florida intermittently is exposed to undesirably high water tables and short-duration floods. In this 3-year study, yield and morphological responses of two sugarcane genotypes to water-table depth and periodic floods were studied. The control treatment was a constant water-table depth of 50 cm. Three other water-management treatments were five (2000) or nine (2001 and 2002) cycles of 1-week flood followed by drainage to 16, 33, or 50 cm for 2 weeks. Yields of one genotype were not affected by periodic floods or drained water-table depth. However, these yields were not commercially acceptable. Yields of the second genotype were high under continuous drain and dropped substantially when exposed to periodic floods. Yields of this genotype were also higher when periodic floods were drained to 50 rather than 33 cm, and 33 rather than 16 cm below the soil surface. The genotype not affected by flood routinely formed air cavities (aerenchyma) within its stalks, but the other genotype only formed aerenchyma after exposure to flood. Results of this study suggest that flood tolerance can be improved by selecting for genotypes that form aerenchyma without exposure to flood. Identification of such will enable sugarcane growers in the Everglades Agricultural Area to reduce drainage to public canals. This will improve soil conservation efforts and reduce harmful export of phosphorus to the Everglades.
Technical Abstract: Sugarcane (Saccharum spp.), the primary crop of the Everglades Agricultural Area (EAA), periodically is exposed to floods for as long as 1 week and high water tables for extended durations. To sustain yields, it is necessary to identify and lengthen high-water and flood durations under which sugarcane yields remain optimum. The purpose of this study was to evaluate the effects of periodic floods followed by drainage to different depths on cane and sugar yields of two sugarcane genotypes. From 2000-2002, experiments with two sugarcane genotypes and four water treatments were conducted outside in lysimeters filled with Pahokee muck soil. Floods were applied for 7 days during five, nine, and nine 21-day cycles in 2000, 2001, and 2002, respectively. Drainage depths for the next 14 days of each cycle were 16, 33, or 50 cm. A fourth treatment was maintained continuously at a water-table depth of 50 cm. Genotype CP 95-1429 yields were not affected by water table or flood. Incrementally lowering the water table by 1 cm resulted in increased CP 95-1376 cane and sugar yields of 0.16 and 0.02 kg m-2, respectively, in 2000; and 0.25 and 0.03 kg m-2, respectively, in 2001. Drained water table did not affect CP 95-1376 yields in 2002. Each day of flood reduced cane and sugar yields of CP 95-1376 by 0.17 and 0.02 kg m-2, respectively, in 2000, and by 0.21 and 0.03 kg m-2, respectively, in 2002. Formation of gas filled channels in the stalks (aerenchyma) before exposure to flood may have accounted for the maintenance of yields in periodically flooded treatments of CP 95-1429.