Submitted to: Journal of Crop Improvement
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/19/2006
Publication Date: 9/1/2007
Citation: Glaz, B.S. 2007. Sugarcane response to month and duration of preharvest flood. Journal of Crop Improvement. 20 1/2(39/40):137-152. Interpretive Summary: Sugarcane, the primary crop on the organic soils of the Everglades Agricultural Area in Florida, is increasingly exposed to undesirably high water tables and short-duration floods. Some growers take advantage of high water tables by flooding fields for one day about 20 days prior to harvest. These floods minimize costly soil fires that ignite on the organic soils when sugarcane is burned before harvest. After about 20 days of drainage, growers report that fields are sufficiently firm to support harvesting equipment while still retaining sufficient moisture to discourage fires. Extending the duration of these preharvest floods would also enhance control of damaging soil insects, reduce subsidence rates of the organic soils, and reduce phosphorus runoff to the natural Everglades. This 2-year study tested yield responses of four sugarcane cultivars, CP 72-2086, CP 80-1827, CP 89-2143, and CP 92-1666, to preharvest flood durations of 0, 10, and 20 days in the plant-cane and first-ratoon harvest cycles. Floods were drained 20 days prior to harvest. Flooding minimally affected sugarcane yields. There was a reduction due to flooding in yields of theoretical recoverable sugar in the plant-cane crop, but not in the first-ratoon crop. Flooding generally did not affect cane and sugar yields per acre except that two of the four cultivars had yield increases only in the plant-cane crop. This new knowledge that, when tested in lysimeters, sugarcane tolerated preharvest flooding for up to 20 days, suggests that follow up field research is warranted to confirm that these floods can profitably expand the flexibility of Florida sugarcane growers in reducing phosphorus discharge to the natural Everglades, reducing oxidation of their organic soils, and in controlling soil insect populations.
Technical Abstract: Some Florida growers apply 1-day floods about 3 weeks prior to harvest to prevent fires that may ignite on organic soils during preharvest burning of sugarcane (Saccharum spp.). Extending these flood durations could improve sugarcane insect control, freeze protection, soil conservation, and reduce unwanted P discharge.Prior studies suggest that extending flood duration to 21 days may reduce cane tonnage and increase or decrease theoretical recoverable sucrose (TRS), depending on month of flood. The purpose of this study was to compare the effects of flood duration and month of flood application on TRS, cane yield, and sucrose yield of four sugarcane cultivars. During the plant-cane and first-ratoon crop cycles, 0-, 10-, or 20-day floods were applied in November or January to lysimeters at Canal Point, FL planted with cultivars CP 72-2086, CP 80-1827, CP 89-2143, and CP 92-1666. Floods were drained 20 or 21 days before harvest. In the plant-cane cycle, TRS declined 0.19 grams sucrose per kg cane per day of flood. Flooding did not affect TRS in the first-ratoon cycle. Yields of CP 72-2086 and CP 92-1666 increased by about 0.7 (cane yields) and 0.08 (sucrose yields) kg per square meter per day of flood in plant cane. Otherwise, flood duration did not affect cane and sucrose yields in either crop cycle. Responses to November and January floods were similar for all flood durations. These results encourage research to quantify the profitability of preharvest flooding of sugarcane, recognizing that these 10-20 day floods had minimal impact on yields while offering potential economic returns from other agronomic and ecologic benefits.