Effects of the topping and harvesting dates upon technological parameters of sugarcane.

Abstract

The youngest internodes of sugarcane have lower levels of sucrose and are rich in compounds that reduce the industrial yield. However, the topping is seldom used by farmers, due to their fearing productivity losses. This research was undertaken to study the influence of the topping and harvesting dates of sugarcane (Saccharum spp.) on the technological quality of stalks. The experiment was carried out in Guariba, state of São Paulo, Brazil, in a completely randomized design with split split-plots and four replications. The laboratory analyses were performed at the Department of Technology of the FCAV-Unesp, Jaboticabal, SP, Brazil. The primary treatments were the sugarcane varieties RB85556, RB855536, and SP80-3280, early, mid-season, and mid-late cycled varieties, respectively, all at the second ratoon. The secondary treatments were the harvesting methods (with and without topping) and the tertiary the harvesting dates (May to September 200). The technological quality of stalks was analyzed through the following parameters: Brix, Pol, reducing sugars (RS), total reducing sugars (TRS) (% juice), percentage of fiber, and productivity (t/ha). The topping of sugarcane resulted in increase of Brix and TRS and decrease of RS. This practice improves the technological quality of sugarcane stems without productivity loss.Additional keywords: Saccharum; varieties; raw-material.