Sequías agrícolas: recurrencia, clasificación y distribución en la Región Pampeana argentina

Abstract

Droughts, phenomenon of high frequency in Pampean Region (Argentina) are studied by means of an agroclimatic index derived from soil water balance, so a different contribution is presented to the subject bibliography. The annual value of soil water deficit is considered as index of the events. They take place almost every year, if not in the whole territory, in some area and temporal space. The resulting consequences are varied in severity, but always have socioeconomic impacts. The evolution and distribution of the events are analyzed and the corresponding climatology is done.

There were used daily precipitation data from the National Meteorological Service for the period 1950 - 2010, mean daily potential evapotranspiration according Penman-Monteith formula, soil water balance considering soil characteristics obtained «in situ» and with the application of Mann-Kendall and Sen non parametric tests. The data series of agroclimatic index values are employed to classified the events severity in mild, moderate, severe and extreme and the trend for each station and different period of time are studied. The annual soil water deficit values are employed as index of the severity classification. The quantity of mild, moderate, severe and extreme events are obtained and the trend for different time periods. Decreasing trends are obtained for the periods 1950 - 2010 and 1961 - 2010. Droughts present decreasing trend for the period of sixty one years (1950 - 2010) and fifty years (1961 – 2010) in almost analyzed stations.