Summary:

In the paper, the agricultural drought was defined as at least the 7-days constant period when the reserve of easily accesible water in the root zone is depleted. Calculations based on meteorological data 1996–2005 from Mochełek (near Bydgoszcz) brought the assessment of beginnings of droughts and their classification in regard of duration. The assumptions of balance method for irri-gation forecast were taken into account. Two types of soil (compact and pervi-ous) and five cultivated plants (spring wheat and barley, faba bean, potato, maize) were taken into consideration. Results of the studies confirmed that within 10-year period in Bydgoszcz surroundings 8–16 agricultural droughts occured (depending on the soil and cul-tivated plant type). The majority of droughts were moderate (series of 7–13 days with accesible water deplation). Severe (series of 14–20 days) and very severe droughts (series over 20 days) made 24% of the total number of drought spells. The qualitative assessment of severe and very severe agricultural droughts pre-sents a good compatibility to particular indexes used for atmospheric drought evaluation.