Redox potential, nitrate content and pH in flooded Eutric Cambisol during nitrate reduction
2007
Wlodarczyk, T.,Polish Academy of Sciences, Lublin (Poland). Inst. of Agrophysics | Szarlip, P.,Polish Academy of Sciences, Lublin (Poland). Inst. of Agrophysics | Brzezinska, M.,Polish Academy of Sciences, Lublin (Poland). Inst. of Agrophysics | Kotowska, U.,Polish Academy of Sciences, Lublin (Poland). Inst. of Agrophysics
Topsoils from 16 arable Cambisols developed from sand, loam and silt were used to study soil ability to nitrate reduction under flooding conditions. The strongest drop of redox potential (Eh) was observed during the first day of soil flooding. Decreasing tendency in pH values was observed in alkaline and neutral soils, and an increase in pH in acid and strongly acid soils, accompanied by a fall in Eh values. Redox potential was negatively correlated with the pH values (R2=0.3041; P less than 0.001). The fall of NO3- varied from 20 to 100% depending on the type of soil and on the time of incubation. With a decrease of nitrate content within the range from 100 to 10 mg NO3- N/kg, the value of redox potential decreased from 250 to 190 mV. The highest reduction of nitrates coincided with Eh values within a narrow range between 200 and 210 mV. Statistical analysis of redox potential in the function of the content of nitrates showed a curvilinear relation (R2=0.3823; P less than 0.001).
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