THE INTERDEPENDENCE OF WATER AND TEMPERATURE REGIMESOF TAIGA-ALAS LANDSCAPES SOILS
Desyatkin R.V., Semenova T.N., Desyatkin A.R.
Institute for Biological Problems of Cryotithozone SB RAS, Yakutsk, Russia
677980, 41 Lenin Ave., IBPC SB RAS, Yakutsk, Russia
tel. +7 (4112) 33 64 71, fax +7 (4112) 33 58 12, - ail: rvdes@ibpc.ysn.ru
The interdependence of the temperature and water regimes of soils on the zone of permafrost is much higher thansomethere. This is conditioned by a several features: the development of soils in yearly thawing through layer, thepresence of closely bedded moisture-proof aquiclude, the weak heat supply and small quantity of falling precipitations.
In such conditions the heat exchange and moisture exchange occurs in thin active layer. The water regime dynamics ofmeadow soils during investigation period can be determined by fluctuations of weather conditions. During theinvestigation time the appropriate layers of meadow soils in Ulakhan Sykkhan alas contained significantly much moremoisture reserves than meadow soils of Tungulu alas. The obtained results show great dependence between temperature
regime and grounds moisture level.
Key words: permafrost, moisture regime, temperature, interdependence

During whole summer season on every site there is
gradual growth in depth of seasonal thawing, thatprocess continues until the third decade of September(see fig. 1).
3,5
3
2,5
2
1,5
1
0,5

Tungulu meadow

18,09,03

09,10,03

08,08,03

29,08,03

04,07,03

24,07,03

30,05,03

10,06,03

10,05,2003

24.09.2002

02.10.2002

20.07.2002

027.08.2002

The interdependence study of water andtemperature regimes of soils during 2002-2003 wasconducted on two meadow soils of model alases
Ulakhan Sykkhan and Tungulu located 4 km from eachother. Both soil sites develop in the same natural andclimatic conditions under the real meadows on the flatarea of central part on aforenamed alases. The
dominating species in meadow associations
composition are Puccinellia tenuiflora with small mixof Glaux maritime and Polygonum sibiricum. The
height of herbage equals to 35-45 cm., the productivityof these meadows in 2002 was 382 tons per km2 and in2003 about 404 tons per km2.
Summer season of 2002 in Central Yakutia waswarm and arid. The average temperature of season was
14º , while the long-term average equals to 12,2º .
During the period between May and the end of October
the precipitations level made only 90.2 mm, but normal
quantity is about 174.9 mm, that is just a little bit
higher than long-term average. Summer of 2003 wascooler for 1° than the warm period of 2002, but it was

The dynamics of depth of thawing

03.06.2002

Observations location and weather conditions

warmer for 0,8° than long-term normal average.
During the period between May and the end of October
the precipitations quantity was 153 mm, while thenorm is 143 mm or for a bit higher than the long-term
average quantity.

30.06.2002

The interdependence of the temperature and water
regimes of soils on the zone of permafrost is muchhigher than somethere. This is conditioned by a several
features: the development of soils in yearly thawing
through layer, the presence of closely bedded moistureproof aquiclude, the weak heat supply and small
quantity of falling precipitations. In such conditions theheat exchange and moisture exchange occurs in thin
active layer. The integral index of intensity of heat andmass exchange of soil active layer on cryolithozone
conditions is the maximum depth of seasonal thawing
through. During years of observations depending on
weather conditions of the season the capacity of active
layer varies within 1.30 and 1.45 m. in forest; within
2.30 and 2.60 m. on tillage; from 0.80 to 1.30 m. on theedge of forest; from 1.00 to 1.15 m. on the layer ofexcess moistening; within 1.35 and 1.65 m. on thelayer of normal moistening and between 2.50 and 3.30
m. on the layer of insufficient moistening.

Depth in meters

Introduction

Ulakhan Sy kkhan meadow

Fig. 1. T he depth of soil thawing

The character of dynamics of thawing depth
growth in both sites does not have difference, thedistinction is only in tempo of thawed layer growth.
Meadow soils of Ulakhan Sykkhan alas thawed
considerably slower than the soils of Tungulu alas. By
the end of season in 2002 the maximum depth ofthawed layer in Ulakhan Sykkhan got 1.5 meters, whilein Tungulu alas 2.9 meters. In the beginning of season
in 2003 soils started to thaw slower than in thebeginning of warm period in 2002. The maximum
depth of thawed soils in 2003 in comparison withprevious summer on Tungulu alas meadows was lessfor 10 cm and on Ulakhan Sykkhan alas was less for 50
cm. The reduction of thawing depth in 2003 can beexplained by the dynamics of weather conditions: thelowering of air temperature and the increase of
precipitations quantity in comparison with 2002 year.

Water regime

The initial reserves of moisture in meadow soils ofstudied alases at the beginning of summer 2002 werealmost identical, total moisture reserves in thawed soils
layer was about 90 mm (Table 1 and 2). By the opinionof Abolin R.I. (1929) in conditions of permafrost zone,
during gradual thawing of frozen horizons get free newconserved moisture reserves, which in capillary way
rise up and provide the requirements of plants. By thetime of second term of observations became apparent
the features of winter moisture reserves in soils. As far
Table 1Moisture reserves in meadow soils of Ulakhan
Sykkhan alas, 2002 (mm)Depth incm

04.06.02

29.06.02

20.07.02

26.08.02

25.09.02

2.10.02.

120-130

17,016,730,826,0130-140

24,515,634,324,3140-150

32,026,0

33,524,6150-160

18,1

14,920,4

16,3160-170

20,7

21,018,3170-180

23,6

19,918,9180-190

9,620,922,2

190-200

18,618,0358,7200-210

22,520,5

as thawing the meadow soils of Ulakhan Sykkhan alaswith large winter moisture reserves dehydrated less,while the soils of Tungulu alas having less wintermoisture reserves dehydrated faster. On the whole themeadow soils of Tungulu alas during summer 2002
were provided by moisture insufficiently, the deficient
reserves of mosture is not enough for optimal
vegetation of meadow flora. Here takes place the fierce
dehydration in the upper one-meter layer, and only at
the third decade of September after precipitations
during brief period of time the upper soils layers get
saturated by the accessible type of soil moisture.
During summer season of 2003 the thawed layer of
meadow soils contained considerably more moisturereserve than in the same soil layer in 2002 (Table 3 and4). The appreciable dynamics of water regime inmeadow soils during the observation period can beexplained by fluctuations of weather conditions.
Table 3Moisture reserves in meadow soils of Ulakhan
Sykkhan alas, 2003 (mm)0-1025,326,1

12,5

11,6

27,3

21,6

10-20

23,7

37,0

15,3

16,2

26,3

26,4

20-30

7,8

22,0

14,1

4,9

5,7

23,6

30-40

13,5

38,5

12,0

5,8

8,1

23,340-50

19,130,4

18,1

5,1

5,2

23,550-60

40,8

37,4

9,9

9,5

15,960-70

44,027,413,7

8,320,070-80

21,8

41,0

13,3

14,4

22,680-90

29,9

32,8

14,2

29,826,390-100

28,435,530,328,634,5100-110

37,932,933,6

31,347,5

Depth incm

30,05,03

10,06,03

04,07,03

08,08,03

29,08,03

09,10,03110-12034,044,531,559,9

0-10

46,956,2

46,5

22,6

37,653,0120-130

28,7

23,3

28,7

36,3

10-20

59,6

70,243,4

29,0

41,3

51,6

18,220-30

34,047,940,027,332,530,425,330-40

49,466,446,833,339,527,840-50

57,556,0

37,147,2

29,050-60

72,553,251,455,7

25,4

74,8

23,0

67,3

8,670-80

7,810,1

6,280-90

8,425,58,2

130-140

39,4140-150

31,1150-160

39,1160-170

28,5
33,0
42,5
42,8

170-180

43,8180-190

50,930,828,3
27,731,330,4

37,136,435,432,4190-200

59,533,5200-210

51,646,190-100

Table 2
Moisture reserves in meadow soils of Tungulu alas,
2002 (mm)Depth incm

03.06.02

30.06.02

20.07.02

27.08.02

24.09.02

02.10.02

0-10

6,712,43,5

4,115,3

8,5

10-20

21,0

4,6

3,6

1,9

8,5

9,720-30

18,8

3,7

2,7

1,4

9,5

5,130-40

15,3

6,8

5,0

2,010,9

6,440-50

28,7

7,9

7,4

2,9

10,8

10,950-60

8,0

4,1

3,0

10,1

17,060-70

9,5

6,6

12,0

13,7

16,370-80

10,9

12,8

13,0

18,8

15,980-90

18,4

14,0

13,0

24,4

27,290-100

21,5

17,4

15,132,132,5100-110

16,6

13,0

19,8

32,533,3

14,2

18,923,925,1110-120

60-70

18,6Table 4
Moisture reserves in meadow soils of Tungulu alas,
2003 (mm)Depth incm

30,05,03

10,06,03

04,07,03

08,08,03

29,08,03

09,10,03

0-10

22,9

15,6

15,6

3,9

20,1

18,8

10-20

21,4

12,9

9,9

11,8

13,8

18,8

20-30

10,8

19,2

21,6

9,5

9,4

11,3

30-40

9,2

15,0

12,0

16,2

12,7

13,2

40-50

14,7

22,1

14,0

7,7

15,850-60

15,3

14,0

14,1

12,5

13,2

10,0

60-70

15,7

12,9

15,9

70-80

15,7

13,5

14,080-90

31,8

21,6

13,490-100

15,1

As is obvious from the mentioned actual data duringthe investigation time the appropriate layers of meadow
soils in Ulakhan Sykkhan alas contained significantlymuch more moisture reserves than meadow soils ofTungulu alas.

The temperature regime

The moisture of landscapes’s active layer plays
important role in forming of the soil temperature
regime. As Kononov K.E. noted (1978), inhydromorphous soils the main mass of incomingenergy consumes for evaporation and only 10%
consumes for thawing of frozen soil and it’s heating. In
soils with insufficient moistening the consumption ofincoming solar energy for evaporation abruptly
decreases and about 50% of radiation balance isconsumed for thawing and heating of soil active layer.
After snow cover melting process in 2002 spring
the investigated soils begin to slowly thaw through andheat up. In upper 0.2 meters-thick layer of Tungulu alasmeadow soils the active temperatures were fixed as
early as in the beginning of June and continued until
the end of August (Fig. 2). Soil temperatures more than>10° by the middle of July reached to the depth of 0.8
meters. Meadow soils of Ulakhan Sykkhan alas heatedup considerably less, the active temperatures penetrated
to the depth a bit more than 0.2 meters (Fig. 3).
2520
15Temperature,

1050-5-10-15-20

0,20,40,6

1,6

2,4

3,20,8

1

20,11,03

30,12,03

30,08,03

10,10,03

10,06,03

20,07,03

30,04,03

15,05,03

10,02,03

20,03,03

10,11,02

28,12,02

20,08,02

02,10,02

11,06,02

10,07,02-25

1,2Fig. 2. The temperature regime of Tungulu alas meadow soils

1510Temperature,

50-5-10-15-20

0.20.40.60.81.2

1.6

2.4

3.2

30,12,03

20,11,0310,10,03

30,08,03

20,07,03

10,06,03

15,05,03

30,04,03

20,03,03

10,02,03

28,12,02

10,11,02

02,10,02

20,08,02

10,07,02

11,06,02-25

1Fig. 3. The temperature regime of Ulakhan Sykkhan alas meadow soils

At both sites exists the dynamics of negative
temperatures in the upper layers of permafrost. Thus,

the temperature of permafrost upper layers in Tungulu
alas meadow soils on the depth of 3.2 meters during all
observation period remained nearly 0° . The amplitudeof negative temperatures fluctuations on upperpermafrost layer amount -0.2° . The insignificant
temperature rise in upper permafrost layer on this site
begins from September-October. Upper layers ofpermafrost in Ulakhan Sykkhan alas meadow soils are
considerably colder than in Tungulu alas. Heretemperature fluctuations in permafrost on the depth of
2.4 meters amount from –0,3 to –2,7° , on 3.2 meters
depth from –1,4 to –3,4° . The maximal rise ofnegative temperatures in permafrost upper layer on thissite noted in October.
Thawing process of surface soil layers in thebeginning of warm season in 2003 started at the last
decade of April. The summer of 2003 was cooler andmore humid than summer of 2002, as the effect of thisthe soils accumulated less heat, that brought toreduction of thawing layer’s thickness in Ulakhan
Sykkhan akas meadow soils almost for 2 times less.
The temperature regime of more moistened soils inUlakhan Sykkhan alas meadows were also significantly
colder than meadow soils of Tungulu alas. The
difference of temperatures at the middle of summer in0.2 meters thick layer reached more than 5° . The
Temperature in 0.2 meters layer of Ulakhan Sykkhanalas soils was about 9,2-12,6° , and in soils ofTungulu alas was between 15,8-19,7° (Fig. 2 and 3).
The similar tendency remained in all depths and dates.
Thereby, the obtained results show great
dependence between temperature regime and grounds
moisture level.

The interdependence of regimes

It is determined that in forming of thermal regimeof meadow soils the moisture reserves in soil active
layer play a big role. At winter season all adsorbed
moisture in soil turns into ice. When moistened soil
freezes it requires more negative temperatures thanfreezing of dry soil. The specific heat capacity equals
to 4.186 kilojoules (kilogram· ), so accordingly whilefreezing of each gram of soil required thecorresponding quantity of heat. Hence, soils containing
more moisture while conversion of water to ice during
autumnal and winter period extract more heat for water
crystallization. During winter such soils accumulate a
big amount of coldness.
The reverse effect is observed while thawing ofmoistened soils, it requires more heat for melting ofsoil ice. The warmth of melting of ice equals to 249,9
joules per gram, consequently for thawing ofmoistened soil it needs according quantity of energy.
For example, at autumn 2002 in active layer of
Ulakhan Sykkhan alas meadow soils the content ofmoisture was 6337 tons per hectare, and in soils ofTungulu alas was 3587 tons per hectare. In 2003
correspondingly 2402 and 1345 tons per hectare.
Accordingly for freezing and thawing processes ofUlakhan Sykkhan alas soils it needed in 2002 a 1.77
times more energy and in 2003 1.78 times. As a resultof such case soils of Ulakhan Sykkhan alas thawed forless depth and heated up considerably slower than soilsof Tungulu alas.
Thereby, on the zone of permafrost the moisturelevel of active layer presented as the determinative
factor of soil temperature regime.
References:Abolin R.I. The geobotanical and soil description ofLena-Viliy plain. – Leningrad., 1929, vol. 10. –378 p.
Kononov K.E. The ecological factors of meadow
cenosis forming and development on flood-landsof Lena river. – In book: Ecology and cenology
of meadows in Central Yakutia. Yakutsk, 1978,
7-37 p.