Climate in Kami-Yuchi brand potato-producing district in Wakkanai, Hokkaido, Japan

Abstract

　Potatoes grown in Kami-Yuchi district, the northernmost hilly part of Hokkaido, Japan, were well known and popular for their delicious taste. They were called "Yuchi-potato". However, farmers gave up their cultivation 60 years ago after the introduction of dairy farming in the district. Some farmers have recently tried to revive Yuchi-potato production, thinking that meteorological conditions in the district are favorable for high quality potato production. We examined this perception as follows. We compared normal values of meteorological factors in Kami-Yuchi district with those in other potato-producing areas of Hokkaido (Nayoro, Kitami, Biei, Kutchan and Memuro). Precipitation is within a suitable range. Although sunshine hours in Kami-Yuchi are moderate among the compared areas, there are many total sunshine hours in the growing season. This is because of a long growing season caused by the low temperature. Although the diurnal range of air temperature in Kami-Yuchi is smaller than those in Biei and Nayoro, the temperature in Kami-Yuchi (maximum, minimum, mean, nighttime in a day) is lowest, particularly in low-altitude locations along rivers, which could rise starch value.