Abstract

The impact of global warming on rice production has aroused considerable concern. In China, rice cropping systems are diverse due to the existence of various agro-climatic zones. Hunan Province ranks first in rice production among the provinces in China, and double-rice cropping with early rice grown from late March (sowing) to late July (harvesting) and late rice grown from mid-June to end-October is the main rice cropping system in this province. We analyzed temperature data at six representative locations (Yueyang, Changde, Changsha, Hengyang, Yongzhou and Chenzhou) in Hunan Province to examine inter-annual temperature variations in early and late rice-growing seasons in the province during a period of relative stability in global temperature (1998–2008). Results showed that there was no significant time trend in annual mean temperature at most of the investigated locations, which is consistent with the global temperature change. However, significant warming trend was observed in early rice-growing season at all of the six locations. By contrast, temperature increase in late rice-growing season was not as common and obvious as in early rice-growing season. Our results suggest that the temperature change pattern in early rice-growing season in Hunan Province is different from the global temperature change, and it is necessity to alter the agronomic practices to cope with the temperature increase in early rice-growing season.