Evaluation of water requirement in quinoa producing areas under climate change conditions

Claudia Canedo; Magali García Cárdenas

Abstract

The objective of this research was to analyze the relationship between the probability of rainfall and the requirement of deficit irrigation of the quinoa projected to future conditions of climate change in the Bolivian Highland. This research work comprises three fundamental parts, the analysis of the precipitation frequency in the Highland, the projection of the future conditions obtained by the statistical downscaling of a general circulation model (MCG) and the requirement analysis of quinoa water with deficit irrigation. These three axes enabled the identification of adaptation measures of the quinoa crop under a possible impact of climate change. The frequency analysis of the precipitations in the Highland of Bolivia was carried out following the methodology of the regional analysis of frequencies based on L-moments proposed by Hosking and Wallis (1997). Annual precipitation was determined for a dry year (25% probability of non-exceedance of annual mean precipitation (PMA)), normal (50%) and wet (75%) for each region identified in the Highland from two criteria of homogeneity, which are the PMA and seasonality index of the precipitations. The analysis of the temperature and precipitation projections of four localities of the central Highland (Patacamaya and Oruro) and Southern Highland (Mulatos River and Uyuni) was carried out, through a statistical downscaling under the limits of the General Circulation Model ECHAM5.0 With the conditions laid down by the IPCC (2007) for scenario A2. Finally, the water requirement of the quinoa crop was determined for the present and for the projected conditions in the seasons 2020-2029 and 2046-2055, by comparing the crop yields obtained to rain fed and under deficit irrigation. The results show that precipitation frequencies present differences in the precipitation of the northern, central and southern plateau of Bolivia. For a non-exceedance probability of 50% (normal year), the north and central Highland presents an average precipitation between 404 and 800 mm / year, in the southern Highland between 156 and 400 mm / year. This shows the aridity characteristic of the southern Highland. The minimum and maximum temperature will increase by 2 to 3 ° C in all four locations. Changes in rainfall are lower, precipitation projected for the decade 2020-2029 will reduce by 1 to 4% and by the 2046-2055 annual rainfall will reduce by 1 to 8%. Lower changes are shown for the Central Highland. The application of deficit irrigation shows an increase in yields of the quinoa crop.