Alluvial soils of the Vistula River delta are one of the most fertile soils in Poland. Part of the area is a depression, whose agricultural utilization relies upon the efficient reclamation systems on polders. High ground water levels enhance redox processes, restriction of which is one of more important functions of the draining systems. This paper presents short characteristics of the redox status of alluvial soils in the delta and describes processes and consequences of oxygen deficits in soils. The importance of indices of oxygen deficit for the formation of water conditions, which would favour agricultural utilization of the delta soils, is underlined.