Sugarcane response to water table, periodic flood, and foliar nitrogen on organic soil

Sugarcane (Saccharum spp.) is routinely exposed to periodic floods and high water tables in Florida's Everglades Agricultural Area. Learning sugarcane responses to these conditions will help improve yields. This study evaluated the effects of constant water-table depths, periodic floods, and N on cane and sucrose yields of two sugarcane cultivars. In 2001 and 2002, two foliar N and four water treatments were applied to the first two crop-growth cycles (plant and first-ratoon crops) of 'CP 72-2086' and 'CP 80-1827' in lysimeters filled with Pahokee muck soil. Constant water-table depths were 23,37, and 51 cm. A fourth treatment was flooding for 2 d in each of eight 14-d cycles per year, otherwise its water-table depth was 44 cm. Foliar N did not consistently affect yields. In nonflooded treatments across cultivars and crop growth cycles, for every centimeter increase in water-table depth, theoretical recoverable sucrose decreased by 0.13 g kg(-1), and cane and sucrose yields increased by 0.16 and 0.02 kg m(-2), respectively. By cultivar and crop-growth cycle, the only significant linear responses to nonflooded water-table treatments were in the first-ratoon crop, where for each centimeter increase in water-table depth, cane and sucrose yields increased by 0.38 and 0.04 kg m(-2), respectively. Periodic flooding increased cane and sucrose yields in the plant crop and sustained or improved these yields in the first-ratoon crop. After rains, allowing floods to remain for up to 2 d may improve yields and reduce P discharge to the Everglades.