Agro-climatic suitability mapping for crop production in the Bolivian Altiplano: A case study for quinoa

An agro-climatic suitability library for crop production was generated by using climatic data sets from 20 to 33 years for 41 meteorological stations in the Bolivian Altiplano. Four agro-climatic indicators for the region were obtained by validated calculation procedures. The reference evapotranspiration, the length of the rainy season, the severity of intra-seasonal dry spells and the monthly frost risks were determined for each of the stations. To get a geographical coverage, the point data were subsequently entered in a GIS environment and interpolated using ordinary kriging, with or without incorporating anisotropy. The presented case study focuses on quinoa ( Chenopodium quinoa Willd.), an important crop in the region that is cultivated during the short and irregular rainfall season and that is well adapted to the frequent occurrence of drought and frost. The GIS library was used to mark zones where deficit irrigation could improve quinoa production. With a data query, zones were delimited where the irrigation can be useful to stretch the length of the growing season beyond the limits of the rainy season and/or to mitigate intra-seasonal dry spells. Determined net irrigation requirements were used to assess the vulnerability of the delineated zones. Two regions with a high vulnerability, a severe drought risk and an acceptable frost risk are the eastern region of the Altiplano and the inter-salt depression region in the south. Together, they account for around one-third of the Altiplano area. In 1 year out of 2, irrigation in these regions can strongly improve crop production. The use of irrigation in other regions of the Altiplano will be less beneficial either because the irrigation requirements are low (region around Lake Titicaca), or because the frost risk is too high (the dry west, the south-west, and the region in between Lake Poopo and the Uyuni salt depression). Apart from the presented application, a general view on the climatic system of the Altiplano could be deduced from the library. The proposed routine in this study yielded a straightforward method to deal with large sets of detailed climatic information and to link them with practical agricultural advice. By redefining query limits and incorporating other data, the GIS library can be used for impact assessments of other agricultural practices and for studying the effects of climate change and of the El Niño Southern Oscillation on quinoa production in the delineated zones.