Upload
nyamdavaa
View
955
Download
0
Embed Size (px)
DESCRIPTION
Mongolian soi erosion study
Citation preview
Environment problem and Soil degradation in Mongolia
O.Batkhishig Institute of GeographyMongolian Academy of Sciences
Introduction• The Mongolia is Central Asian country with extra-continental nature
climate conditions and domination of dry steppe and Gobi-desert nature.
• Over the centuries living people on this land employ by nomadic husbandry. The nature condition of this land was keep pristine feature after long time harmonic relation between human, livestock and nature. These ecosystems have developed under highly variable climates, and are sensitive to grazing management and to changes in rainfall and temperature.
• The pristine grassland ecosystems develop rich fertile soil that have supported nomadic pastoralists for centuries.
Soil degradation and pollution becoming very serious problem in Mongolia, recently.
Up to 60 % of soil cover affected by soil erosion and soil fertility declining.
Soil degradation appears as a major limitation for increased food production.
Last decades Soil pollution in Mongolia increasing, due of gold mining where using mercury and cyanides. Soil pollution impacted on ground and surface water quality.
Result of soil pollution in several places in Mongolia died livestock, and human health problem. Such as Khongor, Boroo, Bayankhongor.
Problem
Causes of Soil degradation
• Climate warming: last 60 years Air temperature increase is 1.9o C,
(world 0.6o C)
3 times faster than world average Precipitation decrease 10 % Permafrost melt accelerating
• Human negative impact Pasture pressure, overgrazing Mining Agriculture soil erosion Road erosion
Permafrost melting
Melted pingos
Soil drying
Wetland decline
Most soil degraded and polluted area
is Central Mongolia, where more human impact
Soil erosion risk map
44,5 % or 700 thousand km2 area occupied by arid land or Gobi desert vulnerable for soil degradation
Pasture pressure, overgrazing impact on soil cover
• Number of livestock in 2007 reached up to 40 million head. Increase 15,7 % or 5,5 mln comparing 2006.
In Mongolian land number of livestock never reached 40 mln.
• Number of Goats increasing due of high price of cashmere. 2007 counts 18 mln or 45.6 % of total livestock.
• Goat is most destructive animal for pasture and soil, eat grass with roots.
• Over 60% of total pastureland is overgrazed. Pasture capacity overloading. But result of surface water shortage many of pastures not used.
A
B
C
0 10 20 km
Turag ---- --Shagnuul --
Noyon -
Sevsuul -
Dalbaa -
Borsog -
B – low grazed
C – non grazed
A - overgrazed
Overgrazing impact on soil
properties in case study of Eastern Hovsgol lake are
Soil temperature and moisture
y = -0.0511x + 13.173y = 0.079x + 9.2521
0
5
10
15
20
25
5 10 20 5 10 20 30 5 10 20 5 10 25 50 5 10 20 40 5 10 20 30 40 5 10 20 30 40 5 10 20 40 5 10 20 40 5 10 20 5 10 20 40 5 10 20 40
SU SL SU SL SU SL SU SL SU SL SU SL
BRG DLB SVL NYN SGL TRG
To C
0
5
10
15
20
25
30
35
40
VW
C %
Moisture VWC % To C Linear (Moisture VWC %) Linear (To C)
Soil humus
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
SU SL R NL SU SL R NL SU SL R NL SU SL R NL SU SL R NL SU SL R NL
Borsog Dalbay Sevsuul Noyon Shagnuul Turag
%
Soil Ammonium and Nitrate
0,0
0,5
1,0
1,5
2,0
2,5
3,0
SU SL R NL
SU SL R NL
SU SL R NL
SU SL R NL
SU SL R NL
SU SL R NL
Borsog Dalbay Sevsuul Noyon Shagnuul Turag
Am
mo
niu
m m
g/1
00g
0,0
2,0
4,0
6,0
8,0
10,0
12,0
Nit
rate
mg
/100
g
Nitrate mg/100g Ammonium mg/100g
Linear (Nitrate mg/100g) Linear (Ammonium mg/100g)
Livestock dung and manure have a direct increasing impact of soil Ammonium Nitrogen content. In the non grazing south slope soils of Dalbay valleys Ammonium content ranges 2,24-2,41 mg/100g, but in the heavy grazing Turag valleys soil Ammonium content ranges up to 3,80 - 4,58 mg/100g or increasing 50-80%.
Soil and pasture degradation accelerating Desertification in Mongolia
DESERTIFICATION
• 90 % of territory affected by desertification by 2006. – Slightly 37,2 % – Strong 34.0 %– Very strong 7.0 %
• last 40 years sand area increased by 3800 km2
This is 8.7 % of all sand area of country – Gobi region 3360 km2 88% – Khangai region 460 km2 12 %
• Between 1990 and 2005 arid area increased 5,4 %.
LAND COVER CHANGE OF MONGOLIA BY NOAA SATELLITE IMAGES
2002 îí
1997 îí1992 îí1992 1997
2006
Water
Coniferous forest
Rocks
Deciduous forest
Glaciers
Grassland steppe
Agricultural field
Dry steppe
Desert
Increasingaridization
Soil wind deflation and dust storms increasing
50 Days in year With dust storms
Agriculture field in Mongolia
Agriculture soil degradation
• Nearly 60% of total arable land or 0,7 million hectare area not more used as a result of degradation.
• It is estimated that over the past 30 years about 35–50 tons of soil have been lost from each hectare of cultivated land due to wind erosion alone.
• 46.5% of arable land was degraded: 12.9% - strong, 28.2% - medium, 58.9 % slightly degraded.
•
Strong, 12.9
Medium, 28.2
Sligthly, 58.9
Arable land degradation of Mongolia, (%)
Soil erodibilityNumber of samples
Average humus content
%
Decrease percentage comparing with non
eroded soils
Non eroded area
388 2.64
Slight 342 2.50 7.2
Moderate 195 2.08 21.3
Severe 88 1.60 39.4
Changes of soil erosion and humus content
Agriculture soil Erdenesant
Argalant
Pasture and abandoned agriculture field in Argalant soum of Central aimag
Erosion rates
Maximum erosion rates 110.2 t/ha/year
Average erosion 19.29 t/ha/year
Erosion area 59.5 %
Upper and middle slope 8-10o
Sedimentation rates
Maximum sedimentation rates 223.7 t/ha/year
Average sedimentation 25.14 t/ha/year
Erosion area 40.5 %
Lower slope and plain
Agriculture fields of Argalant area
Erosion rates 7.8-11.0 t/ha/year
Average erosion 9.2 t/ha/year
Abandoned year 1990
Plain
Mining soil degradation and pollution
Hongor
Zaamar
Bayankhongor
Uyanga
Baga Gobi
Boroo
Tamsag
Nariin sukhait
Tavan tolgoi
Pollution by mercury and cyanide
Road erosion in arid ares
Ouy tolgoi
Tumurtei
Choir
Mining soil pollution by mercury and Cyanide (2007)
Province (aimag) Places Volume m3 Area hectare
Bayankhongor 13 1189 2,4 well 22
South gobi 5113000 23,6
EastGobi 16
Bulgan 2
Central 2 11610 3,87
Selenge 5 174676,8 22,17
Darkhan-Uul 3 2485 1
Uvurkhangai 420 0,042
Sukhbaatar 128 0,4
TOTAL 203508,8 53,5
Ministry of Nature and Environment of Mongolia, 2008
Road erosion
Gobi (Semidesert) Brown soil
Mining soil erosion
• Since1975 total mining eroded land was 500 mln m3 • 300 mln m3 soil eroded after 1990-s “Gold fever”
Illegal gold diggers in 2007 count 65 000 peolpes. Distributed 16 aimag 80 soum Bayanhongor 24400 Uvurkhangai 15700
84%
16%
Mining soil erosion area
Eroded land 13718.5 ha Reclamation 2553.2 ha
Naturally regenerated soil after 100 years mining erosion
10 cm thick humus layer
Non eroded soil
25 cm thick humus layer
Eroo river basin, North Mongolia
Drying of top part Of Alluvial soils
In 1987 permafrost active layer depth was 1 meter In 2007 no permafrost
Soil propertis change
Alluvial soil covered by sand
Change of soil characteristics of Tuul river valley
Zone
Change value in year 2007 comparing with year 1987
Top soil depth cm.
pH (H2O)
Organic matter %
Exchangable cmol/kg Ca:Mg
Ca2+ Mg2+
Forest-steppe (Terelj) -1,6 0,1 -0,5 -0,4 -3,4 1,5
Steppe (Ovoot) -3,3 -0,2 -0,6 0,0 -1,0 0,3
Salty floodplain (Lun) -0,9 -0,3 -0,3 2,6 -1,5 1,2
Boggy floodplain (Bor bulan)
-1,8 -0,9 -2,5 -13,9 -0,2 -2,2
Average of Tuul river vallye
-1,7 -0,4 -1,2 -4,4 -1,3 -0,1
Zone Change % in year 2007 comparing in year 1987
Forest-steppe (Terelj) -17,9 2,2 -6,3 2,4 -43,9 112,1
Steppe (Ovoot) -16,7 -1,9 -23,1 10,5 -15,3 20,5
Salty floodplain (Lun) -13,3 -4,0 -19,7 9,7 -27,9 93,6
Boggy floodplain (Bor bulan)
-23,3 -11,2 -41,4 -28,1 5,4 -21,3
Average of Tuul river vallye
-18,4 -5,2 -25,8 -6,1 -16,2 41,7
• Last decades Soil degradation in Mongolia increasing result of climate warming and human impact.
• Need to comprehensive methods and approaches against soil erosion and pollution problems.
• This problem threatens not only food production of country also whole economic development.
CONCLUTION
Thank your for attention