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4
86%
ODR was calculated for the soil water extracts prepared from freshly taken soil, wet soil stored in plastic bags and air dry soil. ODR in KCI solution was used as reference.ODR recorded for the extracts obtained from freshly taken soil was lower than for the extracts prepared from the stored soil samples. This indicates that for ODR measurements fresh soil should be investigated.
Influence of the measuring procedure on the repeatability of measurement of the potential oxygen flux density in the soil has been presented. Five measuring procedures were applied: measurements taken one directly after another, reinstallation of the electrode after each measurement , reinstallation of the electrode after each measurement with a simultaneous mechanical cleaning of surfaces, measurements with 15-min breaks between consecutive measurements, measurements with electrochemical "cleaning" of the electrode surface.The OFD value was determined by a voltamperometric method using a tri-electrode measuring system. It was found out that the best repeatability can be obtained by repeating the measurement with 15-min (or longer) time intervals.
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.
The relationship was examined between soil moisture tension expressed as soil water potential (pF) and microdiffusion of oxygen (ODR) values. Homogenized samples from various horizons of Eutric Fluvisol and Eutric Histosolwere investigated at 4 pF values (1.5; 2.2; 2.7; 3.2) using the classical Richard method. Oxygen diffusion rate (ODR) was measured in soil samples at these pF values according to theLemon and Ericksson method (1952),modified byMalicki and Walczak (1983), using platinum and reference electrodes. The highest values of ODR ranging from 59.3 to 74.9 μg O₂m⁻²s⁻¹ were formed at pF 2.2 forEutric Fluvisol.Meanwhile, the maximum values of ODR forEutric Histosolranged from 86.4 to 108.1 μg O₂m⁻²s⁻¹ at the pF 3.2 were estimated. The lowest values for ODR for bothEutric Histosol and Eutric Fluvisolwere found at pF 1.5.
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