Estimation of Meteorological Ecology of Soybean (Glycine max Merrill) for Crop Cultivation Regions of North Korea

The meteorological ecology of a soybean variety (Glycine max Merrill) and its characteristics are important factors in selecting soybean variety suitable for the environment. This experiment was conducted to estimate the meteorologicalecological characteristics of soybean for 27 crop cultivation regions in North Korea. The meteorological ecology of each region was determined by the last harvest date and the maximum growth day determined using the daily minimum temperature of the region. The soybean meteorological group for 27 regions in North Korea was classified by eight groups. The last harvest date of group I, the south-west and south-east areas, was from October 21 to 29, which was the latest harvest date among the eight groups. It became shorter toward the central inland and mountainous areas of group IV, and it ranged from September 18 to October 2. The maximum number of growth days was 153~160 days in group I, and 100~111 days in group IV-3, the northernmost area of the east coast. Assuming total growth days as 110 days, the ranges of last flowering dates (and the day length) of group I, II, III, and IV were August 12~19 (day length of 13.5~13.8 h), August 2~6 (14-14.2 h), July 27~August 2 (14.2~14.4 h), and July 10~22 (14.5~14.8 h), respectively. The accumulative temperature of 110 growth days was above 2,400°C in group II-1, the south to north area of the west inland, and above 2,300°C in all regions except Cheongjin, Seonbong, and Jung-gang. The accumulative temperature calculated based on the maximum growth day was above 3,000°C in group I and II-1 and above 2,500°C in group II-2, the central area of the east coast, III-1, the central inland area, and IV-1, the central inland mountain area.