Winter chilling damage risk zoning for watermelon and vegetables in the Hainan Island

The Hainan Island, a vital agricultural zone in winter for watermelon and vegetables in China, often suffers from chilling risk during production. Using natural disaster risk analysis theory, data on daily meteorology, crop yield and planted area of watermelon and vegetables as well as chilling disaster and DEM, the paper constructed the chilling grade index in accordance with the biological characteristics of watermelon and vegetables, and built a comprehensive model integrating hazard index, damage environment index, damage loss index and damage prevention capability index to assess chilling risk of watermelon and vegetables in the Hainan Island. The results showed that hazard index for watermelon decreased from the central part to the east and west of the Hainan Island. It increased from south to north for cowpea and luffa, and increased from southeast to northwest for paprika. Furthermore, distribution of various grades of hazard index was different. Damage environment index reduced from central Wuzhishan Mountain to the peripheral regions. Chilling damage loss index and prevention capability index differed in different regions. Overall, the comprehensive chilling risk index was similar in zoning for watermelon and vegetables, and was higher in the center and north while lower in the south, east and west coastal areas. The characteristics of chilling risk distribution, mainly induced by cold air action and topography, conformed to real chilling conditions in the Hainan Island. The results provided useful information that contributed to better understanding of chilling disaster risk of watermelon and vegetables in the Hainan Island. The results were also useful for policy formation on disaster risk management in the Hainan Island.