Abstract
Double cropping (DC) of corn (Zea mays L.) can be applied to produce high-quality whole crop silage twice a year. In this study, recent expansion of areas suitable for corn DC in the Japan’s Kanto region was investigated and the future situation was predicted. The effective cumulative temperature (ECT, 10°C basis) from April to December during the period from 1980 to 2009 was calculated for every third grid square (approximately 1km × 1km), and the decadal average ECT for the 1980s, 1990s and 2000s was calculated for all squares. Areas suitable for corn DC were taken as those with ECT values exceeding 2,300°C. In the Kanto region, the ratios of areas suitable for corn DC in the 1980s, 1990s and 2000s increased from 2.6% to 13.8% and 20.0%, respectively. Using a Meteorological Research Institute (MRI) model, the potential increase in mean temperatures until the 2080s was estimated. With data from the 1980s and 1990s as a base, the results suggested that mean temperatures would be 1.2°C and 2.3°C higher in the 2040s and 2080s, respectively, indicating that 44% and 60% of the Kanto region will be suitable for corn DC in the 2040s and 2080s, respectively.
