Anna I. Davydova, Sergei P. Davydov, Dmitriy G. Fyodorov-Davydov, Marina V. Schelchkova. The organic matter and movable biophilic mineral elements of high-latitude steppes soils

Oral presentation

The organic matter and movable biophilic mineral elements of high-latitude steppes soils

Anna I. Davydova¹, Sergei P. Davydov¹, Dmitry G. Fyodorov-Davydov² & Marina V. Schelchkova³

¹ North-East Science Station, Pacific Geographical Institute FEB RAS. Cherskiy, 678830 Russia
² Institute of Physicochemical & Biological Problems in Soil Science RAS. Pushchino, 142292 Russia
³ 3Ammosov’s North-Eastern Federal University, Yakutsk, 677980, Russia

High-latitude steppes (HLS) were widespread and had zonal ecosystem status in the Pleistocene. Similar steppes were represented the vast part of the Beringia tundra-steppes. Now the steppe patches survive on steep slopes under southern aspects. Nevertheless they serve as unique information sources about the Beringia “mammoth” steppes. A three-year study for total (TOC) and dissolved organic carbon (DOC), dissolved total nitrogen (TN), soluble reactive phosphate (SRP) in two types of HLS soils of the Kolyma Lowland, Eastern Arctic has been carry out. They are presented petrophytic steppes (PS, more 65 vascular species) which were formed on rock weathering crust and thermophytic steppes (TS, more 35 species) formed on Pleistocene loss-rich sediment of Ice Complex. Hydrothermal and physicochemical soils properties strongly differ from soil properties of a zonal taiga and tundra. HLS soils have about neutral pH and Ca dominates for the exchange adsorption complex, high contents of soil organic matter (SOM) and DOC (to 590 mg), TN (to 80mg, including NH4-N to 250g/100g soil) and highest value of labile P (PO4-P to 1200g/100g soil). SOM varied from 2.0 to 10.2% in humus-accumulative horizons and 0.6-1.9% of mineral part. SOM distribution has accumulative type and humus-fulvate composition of humus of the upper part. The soil biophilic elements in comparison with Beringia sediments has both similarity (TOC and DOC were comparable) and differences (SRP is higher in several times, but this trend is the reverse for NH4-N).The research was supported by the RFBR (projects 07-05-00313-а and 15-44-05109 r_vostok_a).