Abstract
Polaris, [N, N-bis (phosphonomethyl) glycine], was evaluated as a chemical ripener of sugarcane in small, replicated field plots and commercial-scale trials to determine optimal rates and time of application. When used early in the harvest season (December-January) in a field-plot experiment, Polaris at 2.24, 4.48, and 6.72 kg/ha at 6 weeks after application gave significant increases in sucrose-percent-cane over the untreated control. In addition, 6.72 kg/ha produced significant increases in sucrose over 2.24 kg/ha. At 8 weeks after application, the 6.72 kg/ha rate showed significant increases in sucrose over the control. For late harvest season application (May-June), Polaris at 6.72 kg/ha significantly prevented decreases in sucrose at 2 and 4 weeks, but not at 6 or 8 weeks after application. With 6.72 kg/ha of Polaris, the early-harvest application averaged a 12.9% increase in sucrose over control (10.74 vs 9.51) as compared to 7.3% for the late-harvest application (10.44 vs 9.73). Commercial-scale trials used 3.36 kg/ha of Polaris by airplane on test sites on the humid north coast and irrigated southern coast. A significant response was found for the combined north coast trials at 4 weeks after application, with sucrose increases ranging from 9 to 15% over the controls.