Variability of acidity, electrical conductivity and redox potential in two Podzols at the Smolenskoye Poozerye national park
Authors:   Lomonosov Moscow State University, Enchilik Polina R. ,   Center for Problems of Ecology and Productivity of Forests, Russian Academy of Sciences, Klink Galina V. ,   Institute for Information Transmission Problems named after A.A. Kharkevich RAS, Peunova Alisa A. ,   Lomonosov Moscow State University, Prilipova Elena S. ,   Lomonosov Moscow State University, Sergeeva Elizaveta A. ,   Lomonosov Moscow State University, Sobolev Nikolay S. ,   Lomonosov Moscow State University, Semenkov Ivan N. ,   Lomonosov Moscow State University; Center for Problems of Ecology and Productivity of Forests, Russian Academy of Sciences
Published: October 2024

Variability of acidity, electrical conductivity, and redox potential depends on processes affecting the soil quality. The study of these properties is important in planning and analyzing the results of ecological and geochemical monitoring. The purpose of the work is to assess the intrahorizontal variability of acidity, electrical conductivity and redox potential within different depths of automorphic sandy soils of the Smolenskoye Poozerye National Park. Variability of pH values, electrical conductivity of water extract, and redox potential were studied in each horizon of the postagrogenic Entic Rustic Podzol under a birchoak-spruce forest and the Katogleyic Albic Carbic Podzol under pine-spruce forest located at the Smolenskoye Poozerye National Park (55°32′ N, 31°24′ E). Entic Rustic Podzol was sampled at seven depths in five repetitions. Samples were taken from the Katogleyic Albic Carbic Podzol from nine depths in triplicate. The pH values, electrical conductivity, and redox potential of the samples from Entic Rustic Podzol were measured five times in aqueous suspension within one day after sampling and once in Katogleyic Albic Carbic Podzol. The variability of the physicochemical properties of soils in each data set was estimated using the three groups of coefficients of variation. In the Entic Rustic Podzol, Cv1 was a measurement variability calculated for five repeated measurements of the same suspension, Cv1av was averaged Cv1; Cv2 was calculated for averaged values of five samples which suspension was measured five times. Cv for Katogleyic Albic Carbic Podzol was calculated from three samples from nine depths and for Entic Rustic Podzol from the first measurement of five in each of five suspensions from seven depths. Variability of properties of all studied soils was at a low level: Cv < 50%. In comparing with the coefficients of variation calculated for pH and electrical conductivity in different soil horizons, the averaged coefficients of variation of the same properties, which were calculated for the whole data set characterizing Entic Rustic Podzol variability, were generally lower. The variability of the electrical conductivity was the highest among all the parameters studied, and the variability of the redox potential was the lowest. In the Katogleyic Albic Carbic Podzol, acidity variability increased in the Bs horizon. The variability of the redox potential was increased in the uppermost part of the humus horizon. The variability of electrical conductivity was maximum in the middle part of the profile and it was present in an extremely small amount in lacustrine sands with an uneven distribution of electrolytes. In the Entic Rustic Podzol, the variability of acidity increased in the middle part of the profile due to accumulation of Fe and Al fulvates. The variability of electrical conductivity varied slightly along the Entic Rustic Podzol profile. The variability of the redox potential was maximum in the forest litter, since the values of this parameter depend on the variability of moisture and microbiological activity.