2021 Volume 14 Issue 2 Pages 81-88
Forecasting sugarcane yields from evapotranspiration is useful in Okinawa because water resources are limited and unstable. In this report, the evapotranspiration in a sugarcane field was estimated using the improved tank model that incorporates the radiation method that takes into account changes in soil moisture content. The purpose of this study is to clarify the relationships between estimated evapotranspiration(ΣETe) and dry weight production(DW) in fields where sugarcane is cultivated with different m e t h o d s and in different seasons in the southern part of Okinawa Island. The relationship between ΣETe and DW can be approximated by a logistic curve for new planting and a straight line for ratooning, and a significant positive correlation(new planting, r=0.99; ratooning, r=0.99) was observed. The reason for the early growth in ratoonings is caused by the early increase of sprout and leaf area. The DW estimation contributes to forecast yield, and also to make plans for using irrigation water effectively.
