This document describes a study that developed a land suitability model for maize and sorghum crops in northeast Libya using geographic information systems (GIS). The study aimed to create a methodology for predicting land suitability classifications under irrigation. The methodology involved defining land qualities and characteristics, collecting soil and climate data, and overlaying layers on soil, climate, erosion risk, and topography in GIS to produce suitability maps. The findings provided a validated framework for assessing land suitability in the region. The conclusion stated that GIS allows more efficient land evaluation compared to conventional methods.

1. Land Suitability Model Using Geographic
Information System (GIS) for Maize and
Sorghum in North East of Libya
DR BASHIR NWER
GEOTUNIS 2012

2. UNIVERSITY
Land Suitability model Using of Tripoli
(GIS) for Mazie and Sorghum in North East of Libya
1. Introduction
2. Aim
3. Methodology
4. Findings
5. Conclusion
05/04/2008 BASHIR NWER GEOTUNIS 2012 2

3. 1- Introduction UNIVERSITY
of Tripoli
Location of study area
The study area is located in the
strip of the coastal territory and
Jabal Akhdar Upland bounded by
the following coordinate’s lat
30’ 33° 00’ N; long 19° 50’ ‐ 22° 45’E
.
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4. 1- Introduction
UNIVERSITY
of Tripoli
• Land Evaluation
• The need for Land Evaluation
• Land evaluation is a prerequisite in achieving optimal
utilisation of the available land resource for agricultural
production
• It guides strategic land use decision making
• Land Evaluation Methodologies
• Many methodologies exist
• Some systems value the degree of suitability of properties,
others place more emphasis on the limiting factor of soil use
• Some systems Groups land into level of importance (classes,
subclasses), others use mathematical formula
05/04/2008 BASHIR NWER GEOTUNIS 2012 4

5. UNIVERSITY
2- Aim of the paper of Tripoli
The aim of this paper is :
“To develop a methodology for predicting the land
suitability classification for maize and Sorhgum
under irrigation in North‐east Libya”.
05/04/2008 BASHIR NWER GEOTUNIS 2102 5

6. UNIVERSITY
3- Methodology
of Tripoli
(1- 9 )
 Development of Land Evaluation Methodology
• FAO Framework for land suitability was selected
• Defining Land Utilisation Types (Maize and Sorghum )
• Defining Land Use Requirements
• Defining Land Qualities, Land Characteristics and their threshold
values
 How ?
• Critically assessed the literature about land resources in Libya (Soil,
Climate and Topography)
• Review of text and scientific publications to determine the
requirements of wheat for optimum growth
• A list of LQ and LC and their threshold values proposed
• Local knowledge and professional judgements are consulted
• Final LQ and LC and their threshold values are developed
05/04/2008 DR BASHIR NWER GEOTUNIS 2102 6

7. UNIVERSITY
of Tripoli
3- Methodology (2- 9 )
Code Grouping Land Qualities Land Characteristics
c Climate Temperature regime Temperature
s Soil Rooting conditions Rootable depth
Soil Texture
Moisture Availability Available water-holding capacity
Nutrient Availability Soil reaction (pH)
Nutrient Retention Organic Matter (O.M %)
Cation Exchange Capacity (CEC)
Excess of Salts Soil Salinity (EC)
Soil Alkalinity (ESP)
Soil Toxicities Calcium Carbonate (CaCo 3 %)
Infiltration Infiltration Rate
Condition for germination Gravel and Stones %
Oxygen Availability Soil Drainage class
e Erosion Erosion Hazard Soil Erosion (USLE)
t Topography Topography Slope %
DR BASHIR NWER GEOTUNIS 2012 7

8. UNIVERSITY
3- Methodology ( 3- 9) of Tripoli
• A land suitability model was developed using weighed
overlay method in the GIS to produce a land suitability
classification in the study area.
• Four layers ( soil, Climate, Erosion and Topography)
were integrated within a GIS environment and
overlain to produce the
final suitability
05/04/2008 BASHIR NWER GEOTUNIS 2102 8

9. UNIVERSITY
of Tripoli
3- Methodology ( 4- 9)
Inputs
Inputs
Soil, Climate data
Soil, Climate data Building the database
Building the database
And Topography
And Topography Digitise the Maps,
Digitise the Maps, Suitability model
Suitability model
( (paper Maps)
paper Maps) Climate and Soil data
Climate and Soil data
Arc/GIS
Arc/GIS
Outputs
Outputs
Suitability maps
Suitability maps
for selected crops
for selected crops
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10. UNIVERSITY
of Tripoli
3- Methodology ( 5- 9)
05/04/2008 DR BASHIR NWER GEOTUNIS 2012 10

11. UNIVERSITY
3- Methodology ( 6-9)
of Tripoli
 Erosion Hazard
• USLE was applied within the GIS to determine the average
annual soil loss in the study area
• Individual GIS files were built for each factor of the USLE and
combined by cell-grid modelling procedure in the ArcInfo GIS
to predict soil loss in the spatial domain
 Topography
• Topography is expressed as slope percent and derived from the
topographic map
• A layer containing the slope grid for the study area was
prepared as one of the layers
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12. UNIVERSITY
of Tripoli
3- Methodology ( 7-9)
Climate
Climate classification
classification
Soil
Soil classification
classification
Suitability
Suitability
Overlay
Overlay
Assessment
Assessment
Erosion
Erosion classification
classification
Hazard
Hazard
Topography
Topography classification
classification
(Slope)
(Slope)
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13. 3-Methodology ( 8-9) UNIVERSITY
of Tripoli
(Land Suitability analysis and Sensitivity Analysis)
• Overall land suitability based upon equal weighting
for the four layers was determined
• Sensitivity analysis provides further confidence in a
model, and indicates priority areas for refinement if
further versions of a model are to be developed.
Input
Input model Output
Output
model
Vary inputs and observe Effects
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14. UNIVERSITY
3-Methodology ( 9-9) of Tripoli
05/04/2008 DR BASHIR NWER GEOTUNIS 2012 14

15. UNIVERSITY
4-Findings of Tripoli
 A methodological framework for an area of the world never
before assessed, reviewing range of alternative
methodologies considering pros and cons of each in turn
 Compilation of validated and verified key data (fully specifying
parts of the framework ) which addresses the model
specifications identified
 Implementation of a practical information system which
allows the combination of these data sets, together with the
model framework, and which can produce thematic
interpretations (maps relevant to policy)
05/04/2008 DR BASHIR NWER GEOTUNIS 2012 15

16. UNIVERSITY
5-Conculsion of Tripoli
 Computer systems and GIS allow land evaluation to be
performed more efficiently; they limit the margin for
human error, and save time and cost.
 The limitations of conventional land evaluation
methods and the huge administration burden they
create has been simplified and made efficient in this
approach.
 Developing a responsive model, where the changes in
crop production methods could be easily reflected in
the results, supporting further spatial analysis of the
changes, is the only way forward for crop suitability
assessment, especially in Libya.
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