Changes of Redox and pH Conditions in a Flooded Soil Amended with Glucose and Nitrate under Laboratory Conditions

The changes of soil Eh and pH during decomposition of nitrates at different levels of glucose (0%; 0, 5% and 1.0%) and nitrates (0%; 0,5%; 1% and 2% KNO3) in water saturated soil samples (Ah horizon of a Mollic Gleysol) were examined. It was found that in the presence of 0–2% nitrates and 0,5–1% glucose in the soil with 1–2 days anaerobiosis at 20°C resulted in the increase of reduction processes and a decrease of redox potential up to 500 mV (Eh). Soil pH increased in the range of 2.5 units. The results from the model experiment ‐ implying Eh > 200 mV and pH < 6.5 as range of nitrate stability in the soil studied ‐ can be useful for field conditions both to predict the stability of nitrates in the soil environment and to create proper conditions for the effective use of carbon sources as a main factor of redox transformations.