manifestation of land use/land cover change analysis and its impacts on soil properties in gadarif...
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Manifestation of Land Use/Land Cover Change Analysis and Its Impacts on Soil Properties in
Gadarif Region, Sudan
Faculty of Forest, Geo and Hydro Sciences, Department of Geosciences, Institute for Cartography
Khalid Guma Biro, PhD student
Supervisor: Prof. Manfred Buchroithner
Fortaleza, Ceará, Brazil, 01 – 12 November 2010
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Main topics
• Use of multi-temporal satellite data for land use/land cover change analysis
• Impacts of land use/land cover changes on soil properties
• Soil compaction and infiltration rate characteristics under three different land use types in dryland vertisols
• Land use analyses in drylands: an object-oriented classification approach using TerraSAR-X data
• Synthesis: Discussion of interconnections and implications for soil conservation, soil management and sustainable land use
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Study area
African Sahel
(Source: NASA Earth
Observatory, 2007)
Gadarif Region East Sudan
Study site:Area: 40 x 30 km²Average altitude: 600 m
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Analysis of LULC change using optical data
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Unclassified (raw) images from Landsat and ASTER data
Acquisitiondate
Sensor Geometricresolution
Spectral resolution
05.11.1979 MSS 57 m 4 bands
12.12.1989 TM 30 m 6 bands
22.11.1999 ETM+ 30 m 7 bands
17.01.2009 ASTER 15 m 3 bands
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Maximum likelihood classification showing LULC through the period 1979 – 2009
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0
200
400
600
800
1000
1200
1979 1989 1999 2009
Cultivated land Woodland Fallow land
Bareland Settlement Water
Are
a (
km
²)
Year
Areas of LULC classes in the study area
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Change detection (%) for the period 1979-2009 (Diagonalrepresents unchanged fraction of each class)
Change fromCultivated
landWoodland Fallow land Bareland Settlement Water
Cultivated land 76 3 10 5 6 0
Woodland 81 4 6 7 2 0
Fallow land 68 2 10 4 16 0
Bareland 57 3 6 31 3 0
Settlement 11 3 4 2 80 0
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LULC changes in the period 1979 – 2009
0
50
100
150
200
250
300
350
400
450
Woodland toCultivated land
Cultivated land toWoodland
Fallow land toCultivated land
Cultivated land toFallow land
1999 to 2009
1989 to 1999
1979 to 1989
Ch
an
ge (
km
²)
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0
10
20
30
40
50
60
70
80
90
100
Woodland to Fallowland
Cultivated land toBareland
Cultivated land toSettlement
1999 to 2009
1989 to 1999
1979 to 1989
Ch
an
ge (
km
²)
LULC changes in the period 1979 – 2009
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Land use analysis using TerraSAR-X data
Study area
Descending
Ascending
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Acquisitiondate
Sensormode
Geometricresolution
IncidenceAngle
07.11.2009 Strip map 4 m 33.32º
12.11.2009 Strip map 4 m 32.25º
Data acquisition
Image filtering
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σ ºdB = βº dB + 10 * Log10 (sin (θloc) (1) (Infoterra, 2008) βºdB = 10 * Log10 (Ks * DN²) (2)
Where:
σ ºdB = backscattering coefficient in dB
θloc = local incidence angle from GIM
βºdB = radar brightness in dB
Ks = TerraSAR-X calibration factor
DN = digital number of TerraSAR-X EEC input image pixel.
Normalize image backscattering coefficient
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Gamma speckle filtering (7x7)
HVHH HH/HV
Raw
Filtered
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Image segmentation
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Segmentation level Scale parameter Colour/Shape٭ Image weight
Level 1 250 0.9/0.1 1 : 1
Level 2 250 0.8/0.2 1 : 1
Level 3 150 0.9/0.1 1 : 1
Level 4 150 0.8/0.2 1 : 1
Segmentation parameters (using multiresolution algorithm of eCognition)
Smoothness/compactness were constant at 0.5/0.5٭
HVHH HH/HV
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Feature space optimization
Classification was based on nearest neighbour classifier using feature space optimisation
GLCM = Gray level co-occurrence matrix
StdDev = Standard deviation
Invert expression also used for select class
feature
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TerraSAR-X land use/cover map
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TerraSAR-X land use/cover map
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TerraSAR-X land use/cover map
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Summary of classification accuracies
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ClassAccuracy (%)
Conditional kappa Area (%)Producer’s User’s
Cultivated land 95 97 0.96 54.75
Harvested land 97 97 0.96 35.65
Fallow land 95 97 0.96 4.37
Woodland 91 86 0.85 0.58
Bareland 97 88 0.87 0.74
Rock 91 87 0.86 0.11
Settlement 1 90 86 0.84 1.46
Settlement 2 87 94 0.93 2.19
Water 100 100 1 0.15
Overall accuracy (%) 94
Kappa coefficient 0.93
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Impacts of land use change on soil properties
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Silt (%) - Mean±SE
0 - 5 5 - 15
Depth (cm)
18
24
30
36
42
Sil
t (%
)
CL FL WL
a
b
c
aab
c
Clay (%) - Mean±SE
0 - 5 5 - 15
Depth (cm)
50
56
62
68
74
Cla
y (
%)
CL FL WL
bc
ab
aaaa
a aa
Sand (%) - Mean±SE
0 - 5 5 - 15
Depth (cm)
0
6
12
18
24
Sa
nd
(%
)
CL FL WL
c
bcac
cb
ab
a
Soil Bulk Density ( g/cm³ ) - Mean±SE
0 - 5 5 - 15
Depth (cm)
1,3
1,5
1,7
1,9
Bu
lk D
en
sit
y (g
/cm
³)
CL FL WL
c
ba
c
b
a
Soil physical properties
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Soil chemical propertiesSoil pH - Mean±SE
0 - 5 5 - 15
Depth (cm)
7,15
7,25
7,35
7,45
7,55
So
il p
H
CL FL WL
bcbc
b b
aa
SOM (%) - Mean±SE
0 - 5 5 - 15
Depth (cm)
0,7
0,9
1,1
1,3
SO
M (
%)
CL FL WL
a a
c c
bb
Available Phosphorus (mg/kg) - Mean±SE
0 - 5 5 - 15
Depth (cm)
-2
2
6
10
14
P (
mg
/kg)
CL FL WL
aa
c c
b b
Exchangeable Potassium (meq/kg) - Mean±SE
0 - 5 5 - 15
Depth (cm)
0,2
0,4
0,6
0,8
1,0
K (
me
q/l
)
CL FL WL
b
b
bc
bc
aba
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Soil penetration resistance
0
0,5
1
1,5
2
2,5
0 5 10 15 20 25 30 35
Cultivated land
Fallow land
Woodland
Depth (cm)
Con
e i
ndex (
Mpa)
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Soil infiltration (Kostiakov model)
0
10
20
30
40
50
60
70
0 20 40 60 80 100 120 140 160 180 200
Cultivated land
Fallow land
Woodland
Time (min)
Cu
mu
lati
ve I
nfi
ltra
tion
(cm
)
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Maps of soil penetration resistance
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Maps of soil organic carbon
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Maps of soil moisture content
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• Use of multi-temporal satellite data for land use/land cover change analyses and its impacts on soil properties in the northern part of Gadarif region, Sudan; 30th EARSeL Symposium 31.05 - 01 .06.2010 - Paris, France. (submitted to Land Degradation and Development, Revised).
• Land use analyses in the African Sahel: an object-oriented classification approach using TerraSAR-X data; 38th COSPAR Scientific Assembly, 18 - 25 July 2010,Bremen, Germany. (Submitted to Advances in Space Research, Revised).
• The effects of different land use types on soil compaction and infiltration rate in the drylands vertisol of Gadarif region, Sudan; Tropentag 2010, ETH Zurich September 14 - 16, 2010. (Under work).
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