Effects of Meteorological Factors including Typhoon on Sucrose Accumulation in Sugarcane during Maturation Period

Abstract

Utilizing the data obtained during the past 20 years, we analyzed the effects of meteorological factors, including typhoons, which were not considered previously, on sucrose accumulation in sugarcane during the maturation period (October to January) using a standard variety “NiF8” in Tanegashima-island. The juice sucrose content was measured periodically and sucrose accumulation was calculated. Multiple regression analyses between meteorological factors and sucrose accumulation were conducted. In the analyses, the effect of a typhoon was defined as the inhibition of photosynthesis caused by leaf lesion and the hypotheses were 1) the inhibitory influence should last from the date of typhoon to 200 °C days in effective accumulated temperature, and 2) the efficiency of utilization of solar radiation should be reduced by the inhibition depending on the wind speed levels. Determination coefficient of the model was highest when the inhibition of photosynthesis was assumed to be 10% at maximum instantaneous wind speed of 20–30 m s^–1 and 60% at that over 30 m s^–1. By including the typhoon effects in the model, the estimated sucrose accumulation was closer to the observation data in 2017/2018 growing season when sugarcane was affected by two typhoons in late October; and, the estimation accuracy was higher compared to the model that did not include the typhoons. Results of the analyses indicated that solar radiation usable by sugarcane from October to December, and temperature and precipitation from November to December had significant effects on sucrose accumulation.