Land suitability expresses how well a tract of land supports a defined use. The application evaluates climate, soil and terrain for a given crop and management system, and identifies the areas best suited for that use.
OutputSuitability map per category and a combined land suitability map
DecisionPrioritisation of areas for a defined agricultural land use
ScaleFarm district to region
Built forA defined crop, season and management system
Default categories
The suggested criteria follow the FAO approach to land evaluation and fall into three categories, each with its own suitability map. These default categories can be renamed or removed by the user, and new categories can be added.
Climate and water
Rainfall, temperature and length of the growing period, and the water available from soil and irrigation.
Soil suitability
Rooting depth, texture and drainage, and the chemical conditions of the soil.
Terrain and access
Slope, erosion hazard, waterlogging and access to markets.
The criteria library is maintained continuously. In each project, criteria can be added, removed or renamed.
Land use type
Suitability refers to one use of the land. The land use type needs to be defined by the user before scoring, because the same soil can be highly suitable for one crop and unsuitable for another.
- Crop
- Growing season
- Rain-fed or irrigated
- Management level
Several criteria act non-linearly or depend on the crop, such as pH, temperature, slope and waterlogging. Their scoring functions are defined by the user for each project.
Constraints
A weighted overlay lets favourable criteria compensate for poor ones. Absolute limitations, such as slopes beyond the limit for mechanised farming or soil salinity beyond the tolerance of the crop, therefore enter as constraints, together with protected and built-up areas. The application suggests none.
From criteria to suitability
- CriteriaStandardised with crop-specific scoring functions
- Category mapsWeights within each category give its suitability map
- Suitability mapWeights between the categories combine the category maps
- Candidate areasContiguous areas of very high suitability in which no criterion falls below a minimum value
Weights come from the analytic hierarchy process, ranking, rating, the multi-influencing factor method or an anonymous stakeholder survey, for example with farmers and extension services.
Results
The result classes rank the locations within the study area by their relative suitability. The map does not apply the FAO limiting-factor classes automatically and does not predict yields.
Sensitivity analysis shows which areas keep their class when the weights change. Validation against existing cultivation or observed yields will follow in a later version.
Typical questions
- Where is a given crop best suited under rain-fed conditions?
- How much additional land becomes suitable with irrigation?
- Which areas are suitable but currently under another use?
- How does suitability shift under the climate of a future scenario?
Case stories
No case stories for this application yet.
References
- Akıncı, H., Özalp, A.Y., Turgut, B. (2013). Agricultural land use suitability analysis using GIS and AHP technique. Computers and Electronics in Agriculture 97, 71–82. doi:10.1016/j.compag.2013.07.006
- FAO (1976). A Framework for Land Evaluation. FAO Soils Bulletin 32. Food and Agriculture Organization of the United Nations, Rome.
- FAO (2007). Land Evaluation: Towards a Revised Framework. Land and Water Discussion Paper 6. Food and Agriculture Organization of the United Nations, Rome.
- Malczewski, J. (2004). GIS-based land-use suitability analysis: a critical overview. Progress in Planning 62(1), 3–65. doi:10.1016/j.progress.2003.09.002
Start a land suitability project
Select “Land suitability” when creating a project. The suggested criteria appear in step 2.