Evolution of drought severity for a 118-year period in the Republic of Moldova

The Republic of Moldova is among several Balkan countries affected by extreme drought. Some districts in the country suffer from severe droughts approximately once per every 3 years, with serious consequences for the agricultural and food sectors. Any contribution to understanding and predicting drought conditions will be a step toward minimizing drought impacts. Droughts in Moldova were evaluated using meteorological data since 1955 and/or a long time series (1891–2009) recorded at Moldova’s State Hydrometeorological Service. Evolution of drought severity for the 118-year and/or 54-year time series is based on the Si-m drought index, using temperature and precipitation series for the calculations. In addition to meteorological data, the crop yields for corn (Zea mays L.), a crop widely grown in Moldova, were used to demonstrate drought impact. The Si-m shows an increasing tendency toward more intensive and prolonged severely dry and extremely dry summer months. The analysis shows that 86% of the poor yield years were recorded for corn when drought occurred during April and July–August. Corn yield is also highly sensitive to the occurrence of a short drought spell in August (e.g., 1994, 1999, 2003 and 2007). Finally, the negative regression coefficient for corn yield indicates that corn is most vulnerable to extreme droughts during April. This was the second cause for poor yields, and particularly in southern districts during 1946, 1947, 2000 and 2009. In these dry steppe areas, extremely dry Aprils may explain 38% of the variability in corn yield.