Using geographical information system to generate a drought risk map for rice cultivation: Case study in Babahoyo canton (Ecuador)

Abstract

Extreme weather events are occurring more frequently, and they affect people, infrastructure and crops. Drought is one of the most important hazards that threaten agriculture and livestock. Such adverse events can result in yield losses over large cropping areas. It is difficult for farmers to cope with prolonged periods of drought. In the absence of government support, rainfed farmers have very limited adaptation capabilities. In this study, we used geographical information system (GIS) tools to generate a drought risk map (DRM) for rice cropping in Babahoyo Canton, Ecuador. This map represents production risks incurred through the onset of a drought event based on the interaction between vulnerability and threat. The vulnerability of rice cropping is determined through a soil land evaluation for rice cropping and the availability of water during the crop cycle rather than approaching the issue based on drought indices, such as the standard precipitation index (SPI). Threat is the likelihood of the occurrence of a drought event that affects rice crops. The DRM was compared to another drought risk map that was generated based only on climatic variables as risk factors (DRcM). We adjusted the DRM and DRcM by adding a layer of operational irrigation projects and by removing drought hazards from areas that are currently irrigated. Based on Normalized difference vegetation index (NDVI) temporal series and drought claims insurance data, the obtained DRM and DRcM were validated. Both maps show a significant relationship between zone classification and NDVI values. However, the DRM adjusted better to insurance data than the DRcM, which does not consider soil variables. The DRM is an effective tool for agricultural risk management decision-making and it serves as an important source of information that could be used for index-based insurance implementation.