Abstract: Based on the daily mean air temperature during the period of 1959-2009 from 82 weather stations and growth period of double-season early rice during the period of 1981-2008 from 14 agrometeorological stations in Jiangxi,the variation of beginning date of 10℃ and its impacts on growth period of double-season early rice was analyzed.The results showed that the beginning date of 10℃ changed obviously during the 51 years and the maximum change range reached 36 days.The decadal variation range was largest in 1980s and 1990s,which was second during 2000-2009,and relatively stable in 1960s and 1970s.The liner trend of the date was not significant in the whole 51 years,while it advanced significantly from 1991 to 2009.The 10℃beginning date's area distribution in the whole province changed significantly in the 51 years,the diving line of March 20th and March 10th expanded southward step by step from 1960s to 1990s,which shrunk northward by a large amplitude during 2000-2009.The change range in Southern Jiangxi was larger than in Northern Jiangxi and Middle Jiangxi.The beginning date of 10℃ positively correlated with the phonological periods of double-season early rice in vegetative growth stage,which were uncorrelated in reproductive growth stage.Compared typical early years of the date with typical late years,the rice's growth phases obviously advanced by average 3.7-9.1 days in vegetative growth stage,which turned to delay in some stations in reproductive growth stage,and the difference between them was bellow 4 days in most stations.The whole growth stage was 3 days longer.The study results could support local agriculture production.

Key words: Jiangxi, Beginning date of 10℃, Phenological period of double-season early rice