Seasonal Fiber Content of Three Sugarcane Cultivars in Three Crop Cycles on Sand and Muck Soils

Accurate seasonal estimates of fiber are needed to maximize profits whether producing sugarcane (Saccharum spp.) for sucrose or ethanol. The main purpose of this study was to determine the effects of sample date and crop cycle on fiber content of three sugarcane cultivars growing on sand and organic (muck) soils, and secondarily to determine if fiber could be reliably estimated 1 mo before the beginning of the harvest season. From September through February, from 2007-2009, fiber content was estimated from monthly sampled stripped stalks of cultivars CP 72-2086, CP 78-1628, and CP 89-2143 growing in three replications of field plots in south Florida in the plant-cane, first-ratoon, and second-ratoon crop cycles on Pompano fine sand (siliceous, hyperthermic Typic Psammaquent) or Margate sand (Siliceous, hyperthermic Mollic Psammaquent), and Torry muck (euic, hyperthermic Typic Haplosaprist) soils. Linear increases in fiber content ranged from 0.07 to 0.28 g kg -1 d -1 . Quadratic models usually predicted maximum fiber content from December through early January. On sand soils, the cultivar rankings were often similar to expectations, with fiber content of CP 78-1628 > CP 89-2143 > CP 72-2086. On the muck soil, CP 78-1628 fiber content was high, but differences between CP 72-2086 and CP 89-2143 were not consistent. For all soils, overall means were often not indicative of fiber status due to significant, but inconsistent interactions. Researchers should analyze fiber content whenever they analyze sucrose content, and mills should monitor fiber content daily of unique cultivar x crop cycle x soil deliveries.