Abstract: Based on the precipitation data from four meteorological stations in Bole Prefecture during 1958-2005, precipitation changes in the growing season of crops were analyzed. The results show that there was a remarkable rise trend for the precipitation in the growing season of crops, with flood years slightly more than drought years since 1990s; the periods of 5-7 years, 16 years, and 30 years were dominant for the mean regional precipitation; the spring-summer drought was very prominent in the Bole River valley since 1990s, which was mainly caused by the precipitation reduction in the upstream of Bole River in May, the delay of the first soaking rain and the decrease of the soaking rain frequency in the midstream of the Bole River. The flood in mountainous area was easily induced by the significant increase in rainfall amount and the frequency of heavy rain from June to August in the upstream of Bole River. The increase in autumn precipitation was unfavorable for crop picking and airing, but it was advantageous for being stored and used in the next spring.

Key words: Bole Prefecture, growing season of crops, precipitation change