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The main controls of soil organic carbon in Russian cryolithozone
O.V.Chestnykh
Forest Ecology and Production Center of Russian Academy of Sciences, Moscow
Correct estimates of soil organic carbon reserves are very important in construction of the global and regional carbon budgets. The general methodical approach to receive above
estimations can be called cartographic. The procedure is next: a selection of some geographical base; collecting of empirical data, corresponding to different polygons of map;
averaging of data within polygons; multiplying of average values on polygon areas; summarizing of all polygon values. In the case of soil carbon estimation the maps of soil types
usually are used as main geographical base. From the other side, the carbon storage in soil is extremely variable even in same soil types. In our work we used also other types of
geographical bases, as map of landscapes (Fig. 1) or map of ecoregions (Fig. 2). The objective of present work was to find the factors, which determine maximal variability of soil
carbon storage values in initial data set. It is evident, that these factors need to be taken into account in developing of appropriate geographical base for soil carbon estimations.
Amongst bedrocks (Fig. 6) the least carbon reserves were found on sands (106.8 tC ha-1), with intermediate reserves on loams and maximal on clay (193 tC ha-1). We
found a decrease of carbon reserves in the sequence of the following soil types (Fig. 7): "sod – peat – brown – podzolic – gleic - grey" within the range from 184.8 tC ha-1 to
100.0 tC ha-1.
200
-1
160
C soil density, t ha
C soil density, t ha
-1
200
120
80
40
0
160
120
80
40
0
Sand
Sandy loam
Loam
Granit
Clay
sod
peat
gleic
grey
Fig. 7. Average Csoil density vs. soil types.
Fig. 6. Average Csoil density vs. bedrock types.
Fig 2. Geographical distribution of Csoil density in taiga zone of Russian
cryolithozone.
podzolic
Soil types
Bedrock types
Fig 1. Geographical distribution of Csoil density in tundra zone of Russian
cryolithozone.
brown
Soil carbon reserves (Fig. 8) in tundra subzones (arctic, typical, south) varied in the range of 95-105 tC ha-1 , whereas in forest tundra and taiga subzones at 141-163
tC ha-1. Soil carbon storage decreased within the following sequence of the main ecosystem types (Fig. 9): meadows, forests, bogs, tundra (165.8, 142.1, 130.2 and
112.6 tС ha-1 , respectively).
-1
200
160
C soil density, t ha
The reserves of soil organic matter were calculated for each soil pit. Horizon thicknesses, bulk weights of
horizons, soil organic matter content (%) in horizons were taken into account. All these data were summarized
by horizons to characterize a particular soil pit. The reserves of soil organic carbon were estimated by humus
content. Empirical data were grouped by selected factors and averaged with standard errors.
200
C soil density, t ha -1
We used an original database "Soils of the Northern Eurasia", including descriptions of more then 1000 soil
pits (Fig. 3). For each pit description the base includes information on 87 parameters, combined to next groups:
descriptive, physical-chemical features, gross chemical content. We selected from database the correspondent
information to cryolithozone of Russia, including all tundra and forest tundra subzones, northern taiga subzone
of Siberia and middle taiga zone of the East Siberia. Geographical latitude and longitude, soil type, bedrock
type, natural subzone and vegetation type were amongst the analyzed factors.
120
80
40
-1
200
160
C soil density, t ha
C soil density, t ha-1
200
120
80
40
0
56-60
60-64
64-68
68-72
72-76
Latitude ranges
Fig. 4. Average Csoil density vs. latitude ranges.
>76
80
40
re
stt
un
dr
N
a
or
th
er
n
ta
ig
a
M
id
dl
et
ai
ga
forest
swamp
cinders
tundra
Vegetation types
Fo
dr
a
tu
n
M
oi
nt
ai
n
tu
nd
ra
ut
h
So
al
Ty
pi
c
meadow
Geographical subzones
Fig. 8. Average Csoil density vs. geographical subzones.
Fig. 9. Average Csoil density vs. vegetation types.
We consider the range of carbon storage variations as a characteristic of relative importance of a particular factor. These ranges in the order of descending importance
were the following: latitude (113 tС ha-1), bedrocks type (86 tС ha-1 ), soil type (85 С ha-1), ecosystem type (53 tC ha-1), natural subzone (39 tC ha-1) and longitude (21 tC
ha-1).
160
CONCLUSION
It is widely accepted by soil scientists that for proper estimation of soil carbon reserves it is necessary and sufficient to consider soil or landscape type maps.
Our basic point is to add into consideration other important factors and to create the specific map, summarizing information on bedrock and soil type with
additional latitudinal subdivision.
120
80
40
0
<56
tu
nd
ra
ra
tu
nd
tic
rc
A
The most evident was a latitudinal trend (Fig. 4). Soil carbon reserves linearly decreased with latitude increase from 162.3 tC ha-1 at 56 N to 49.7 tC ha-1 at 76N (the step in latitude
was 4o). The longitudinal trend (Fig. 5) within the range of 60-150o E and 30o step wasn't found to be apparent.
120
0
0
Fig. 3. The profile of tundra gleic soil of
south tundra subzone (Vorkuta region).
160
<60
60-90
90-120
120-150
Longitude ranges
Fig. 5. Average Csoil density vs. longitude ranges.
>150
SELECTED PUBLICATION
D.G. Zamolodchikov, D.V. Karelin, O.V. Chestnykh. Phytomass reserves and primary productivity profiles of the Russian Nopth from Cola Peninsula to Chukotka. In:
Global Change and Arctic Terrestrial Ecosystem. ECSC - EC -EAEF, Brussels, Luxemburg, 1995. P. 191-200
O.V. Chestnykh, D.G.Zamolodchikov, A.I. Utkin, G.N. Korovin. Distribution of Organic Carbon Reserves in Soils of Russin Forest. Lesovedenie. 1999. No 2. P. 13-21
(in Russian).
O.V. Chestnykh, D.G. Zamolodchikov, D.V. Karelin. Resources of organic Carbon in the Soils of Tundra and Forest-Tundra Ecosystems in Russia. Russian Journal of
Ecology. 1999. V. 30. No 6. P. 392-398.
D. G. Zamolodchikov, V.O. Lopes de Gerenu, D.V.Karelin, A.I.Ivashchenko, O.V.Chestnykh. Сarbon Emission by the Southern Tundra during Cold Seasons. Doclady
Biologocal Sciences. 2000. V. 372. P. 312-314.