The actual state of rice plant damage of Yamagata Prefecture caused by the salty winds of typhoon No.15, 2004 from the view point of typhoon characteristics

Abstract

Rice plants in an extensive area were damaged by salty winds caused by typhoon No.15, 2004 in the Shonai area of yamagata Prefecture. The yield index of rice was the lowest in 35 years. The characteristic of the typhoon was investigated in relation to rice yield. The main factors affecting the yield of rice were as follows. 1) Maximum south-west wind speed higher than 15 m s -1 and duration of strong winds (stronger than 10 m s-1) longer than 5 hours, 2) There was a lot of spindrift caused by mountain waves in the coastline, 3) Sodium, adhered to the rice panicles, was not washed out because of little rain, and 4) The critical rice stage which was sensitive to salt damage coincided with the typhoon. In general, rice yield was lower in the coastal area than in the inland area. The rice yield in the north part of Shonai area was lower than that in the south part of Shonai area probably because the velocity of the wind was higher in the north part and salt particles reached the inland.