Analysis on drought risk of maize in Southwest China based on natural disaster risk theory and ArcGIS

Abstract: Southwest China is an important region for maize production, accounting for about 15% of the total maize area and output in China. There were abundant rainfall and humid climate in Southwest China. But in recent years, severe drought events often occurred there, which caused huge damage to local social economy and attracted widespread interest. Agro-drought risk analysis is helpful for improving the ability of regional disaster management and reducing potential drought risk. In this paper, the daily meteorological observations from 60 stations and the data related to maize agricultural production in Southwest China during the period of 1961-2012 were used. Based on natural disaster risk theory, maize drought risk assessment model was established from four factors: hazard, exposure, vulnerability, drought prevention and mitigation, and maize drought risk was zoned and analyzed in Southwest China. It showed that maize spring drought mainly occurred in most of DistrictⅠ, DistrictⅡand District Ⅲ, maize summer drought appeared in north of DistrictⅠ, most of District Ⅲ and DistrictⅣ, DistrictⅤ and District Ⅵ. High and sub high drought hazard zones of maize in whole growth period were mainly located in District Ⅲ, parts of DistrictⅠand DistrictⅡ. High and sub high exposure zones were mainly located in DistrictⅡ and District Ⅲ; high and sub high vulnerable zones mainly were distributed in east of DistrictⅡ, parts of District Ⅳand DistrictⅤ; low and sub low drought prevention and mitigation zones were located in parts of DistrictⅡand District Ⅳ. The results showed that maize drought high risk and sub high zones in Southwest China were mainly located in District Ⅲ, small parts of DistrictⅠ, District Ⅱ, District Ⅳand DistrictⅤ, in the majority of which maize drought hazards in whole growth period were high or sub high, maize area ratios were higher than maize average area ratio in Southwest, and maize yield per unit was higher than maize average yield per unit in Southwest. Moderate risk zones were mainly located in DistrictⅤand District Ⅵ, in the majority of which maize drought hazards in whole growth period were moderate, maize area ratios, yield fluctuations and yield levels were comparable to maize average productivity level in Southwest. Low and sub low risk zones were mainly distributed in central of DistrictⅠ, southwest of DistrictⅡ, south and east of District Ⅳ, where maize drought hazards in whole growth period were low, and maize productivity levels were different. The study provides a theoretical basis for the maize production risk management and sustainable development in Southwest China.