Oxygen Relationships in a Soil Treated with Sewage Effluent
1975
Klausner, Stuart D. | Kardos, Louis T.
Field plots which have been irrigated with chlorinated secondary treated sewage effluent were examined for their aeration conditions using diffusion chambers and platinum microelectrodes. Average gaseous oxygen concentrations to a depth of 46 cm ranged from 19.6 to 19.0 to 18.4% as weekly application of effluent changed from 0 cm to 2.5 cm to 5.1 cm. Oxygen diffusion rates (ODR) measured by the polarographic method were not significantly different for the three effluent levels and ranged from 22.9 to 19.5 × 10⁻⁸ g O₂ cm⁻² min⁻¹ from the control plot to the 5.1 cm per week plot. Oxygen diffusion rate values diminished with depth with a minimum of 15 at 46 cm and a maximum of 27 at 8 cm. Gaseous oxygen concentration was not affected by crop cover (corn or hay) but ODR was less under hay than under corn. Water samples obtained at depths of 15.2 and 61 cm with suction lysimeters showed significantly greater NO₃⁻-N levels in the 5.1 cm effluent treatment plots, in the corn plot and at the 61 cm depth. Nitrite-N levels were also greater in the 5.1 cm effluent treatment but less in the corn plot than with hay. In all cases, nitrite levels were very low. Ammonium-N levels were also greater in the 5.1 cm effluent treatment but there were no differences with respect to vegetative cover or soil depth. Manganese and iron levels in the soil water were not affected by effluent treatment. Application of 5.1 cm of sewage effluent at weekly intervals has not degraded the aeration status of the soil.
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