Assessment of AquaCrop model on potato water requirements in climate change conditions

Abstract

Potato is the most important non-grain crop in the world. Produced in a traditional way (without irrigation) in Bosnia and Herzegovina averages about 370 000 tons per year. Climate change will probably affect potato crop production, especially due to shallow rooting system. The aim of this paper is to assess the impact of climate change on the potato water requirements for the IPCC RCP 8.5 scenario. AquaCrop V6.0 model was used to estimate potato irrigation norms (In), drainage water and yield. Three distinct area were analyzed; Banja Luka, Bijeljina and Mostar. Climate data were obtained from a climate change simulation of a regional climate model NMMB. The simulation is done as a dynamical downscaling of the global model CMCC-CM over the Southeast Europe. Models are forced with IPCC RCP8.5 scenario. Four periods were analyzed; the reference period (1971-2000) and three time slices in the future: 2020s (2011-2040); 2050s (2041-2070; 2080s (2071-2100). Obtained results in three future periods were compared with referenced ones, and shown as a relative ratio. Sowing dates will be moved towards winter months in all areas. Such results will have an impact on yield increment in rainfed conditions up to 85%. Obtained data showed decrement of the In in Banja Luka and Mostar area up to 18% and 25% through the century, respectively. However, drier conditions in Bjeljina region will affect yield decline. In increment with magnitude of 70% to 34% will be expected in Bjeljina area due to lower precipitation. Thus makes irrigation very important in order to achieve genetic potential of potato. Drainage system should be implemented and/or well maintained in all areas.