02 Contents Frame

Land evaluation – towards a revised framework
104
The farmer-led suitability 
assessment was carried out by means 
of participatory mapping and transect 
walks, field visits, individual interviews 
and ranking exercises. Initially, with 
the help of a few farmers, a map of 
the local land units was drawn and 
georeferenced, based on an enlargement 
of the topographical map at 1:50 000 
scale. Gradually, during visits of other 
farmers’ fields, the map was completed 
and reviewed several times together 
with the farmers. Eventually these 
local land units served as a basis for 
detailed discussion on soils. At least 16 
farmers of different ages in each of the 
villages, cultivating together at least 22 
percent of the village land, participated 
in detailed individual interviews which 
varied in style and format. Both 
formal (structured questionnaire) 
and informal (semi-structured and unstructured) interview techniques were used. 
Information was collected about the soil types within the farmers’ land holding and 
the farmers’ decision-making with regard to crop and soil management. The local soil 
types were ranked according to their suitability for agriculture. During transect walks 
farmers marked the boundaries between different soil types, described each soil type 
and discussed land use, land cover and physiography. 
The researcher-led suitability assessment included two main steps: formal land 
unit delineation and land evaluation. A map of scientific land units was compiled by 
combining the geological map, the topographic map, and data collected in the ITA. The 
methodology for land evaluation developed by Sys et al. (1991b) was applied, including 
a separate climatic and soil suitability assessment for important current or potential crops 
to be grown in the area. This method assesses the fitness of land for a defined use in terms 
of comparative suitability. Using this approach the suitability for 22 crops was assessed. 
The maps produced during the local knowledge study (local land unit map and 
local soil map) and during the formal survey (scientific land unit and soil maps), were 
digitized, labeled and linked with tabular data and recorded soil data within a GIS. 
The dominant local and scientific soil type in each of the land units were compared 
through overlays (Figure A4-4). The relative areas of the prevailing scientific soil types 
within each local land unit were calculated. Through the link established between the 
scientific and local soil types by the integrated transect analysis and soil and land-unit 
mapping, the local land unit map was validated with the information obtained from the 
individual interviews. The integration of the farmers’ and researchers’ maps within the 
GIS made it possible to use transect information in the map.
After completion of the land evaluation, researchers explained to the farmers which 
suitable options were identified for each major local land unit and farmers commented. 
This step led to the revision of the classification and could necessitate changes in the 
final recommendations, where farmers’ and researchers’ opinions and experiences 
could be reconciled.

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