Zornitsa Popova,Maria Ivanova,Veselin Alexandrov,Milena Kercheva,Luis Santos Pereira, Instituto Superior de Agronomia, Universidade Tecnica de Lisboa, CEER-Centro de Engenharia dos Biossistemas, lspereira@isa.utl.pt
Abstract:
This study assesses the vulnerability of Bulgarian rainfed and irrigated agriculture to drought using the WINISAREG model. This model was previously calibrated and validated for maize on soils of small, medium and large water holding capacity (TAW) in various locations of Bulgaria. Simulations are performed for Plovdiv and Sofia. Results relative to Plovdiv show that in soils of large TAW (180 mm m-1) net irrigation requirements (NIRs) range 0-40 mm in wet years and 350-380 mm in dry years. In soils of small TAW (116 mm m-1), NIRs reach 440 mm in the very dry year. NIRs in Sofia are about 80 mm smaller. Rainfed maize is associated with great yield variability. Considering an economical relative yield decrease (RYD) threshold of 60 and 48% of the potential maize productivity in Plovdiv and Sofia, 32 % of years are risky when TAW=180 mm m-1 in Plovdiv, that is double than in Sofia.
Keywords: Drought vulnerability, ISAREG simulation model, SPI-index