ИСТИНА

Pedoanthracological methods are widely used for analysis of the local ecosystem history. We propose the additional using of analysis of patterns of soil profiles to interpret the data on soil charcoal stratigraphy. We present results of the first study on soil charcoal stratigraphy, taxonomy, and radiocarbon dating combined with morphological analysis of soil profiles performed for sandy soil (Podzols and Arenosols) in the Ryazan region in Russia (55.2N, 40.2E). Charcoal samples from the specified soil patterns with a visually high concentration of charcoals were taken from 19 soil pits located in four forest sites. Besides charcoal concentration, which has been defined for all samples, taxonomic identification of charcoals was performed for 24 samples and 12 charcoal samples were radiocarbon-dated. We specifically focused on soils that bear marks of pedoturbations, which included three distinct soil patterns: ancient arable layers, root channels, and pits formed after treefalls with uprooting. We compared samples selected from the specified soil patterns with randomly selected samples. For this, we randomly collected 90 soil samples from different soil horizons in 7 soil profiles located in the same sites. Charcoal concentration in randomly selected soil samples was identified. Results of soil charcoal analysis were compared with pollen and microscopic charcoal analysis of the cores taken in the surrounding peats. Taxonomic composition of trees in charcoal samples was very poor. Pinus charcoals of various age prevailed in all samples. Charcoal of Betula and Sorbus rarely occurred. The oldest charcoals were 2610 cal. BP; the remaining samples were mainly grouped into three clusters: about 2200, about 900–1000, and later 500 cal. BP. Charcoals were unevenly distributed both horizontally and vertically in the soil profiles. Mean charcoal concentration in randomly selected samples was 1.2±0.4 g*kg-1, whereas mean charcoal concentration in ancient root channels originated from artificial tree uprooting (grubbing) was 12.44±3.48 g*kg-1 and charcoal concentration was up to 30.92 g*kg-1 in the ancient arable layer. The largest and most abundant charcoals were located at the greatest depths of ancient pits formed after treefalls with uprooting: mean charcoal concentration was 55.1±23.15 g*kg-1 and the highest one was 133.36 g*kg-1. Periods of charcoal accumulation in soil and in surrounding peats have not coincided. Since 2000 cal. BP the supply of charcoal in the peats had decreased, but translocation of charcoal into mineral soil had widely started due to the pedoturbations as a result of plowing after tree burning and cutting for clearing. These human activities had provided the upper soil layer (arable layers and sometimes root channels) with charcoal fragments. Analysis of ancient pedoturbations allowed us to explain causes of charcoal stratigraphy in the soil and to interpret history of the local sites.