Land capability mapping with SPOT data and geo-information technology south Gondar, North-Western highlands of Ethiopia

Abstract

Land degradation can be considered in terms of the loss of actual or potential productivity or utility as a result of natural or anthropogenic factors; it is the decline in land quality or reduction in its productivity. In the context of productivity, land degradation results from a mismatch between land capability and land use. Land capability mapping is the basis for sustainable development by ensuring correct land use according to its capability for sustained economic production. The purpose of this study was to assess, classify and map land according to its capability to support a range of crops on a long term sustainable basis in Deledel community watershed using on field observation and geo-information technology. The land capability for agriculture classification was developed to describe the agricultural potential of land based on the degree of limitation imposed by its biophysical properties. The classification system was based primarily on slope, land use, soil depth and the risk of soil erosion. This is not a single purpose classification made with regard to land suitability for a particular crop but a general purpose classification for possible potential crops. Then a combination of physical parameter required for the classification was defined and identified. The classification concept is based on an integrated scheme with three GIS layers of slope class, soil depth, and risk of soil erosion class. These layers were rasterized and used for layer formation and analysis. The resultant map displays the land units according to their inherent characteristics and indicates the capabilities for various types of land utilization. The analysis reveals that class I, II, III and IV (Suitable for annual crops) can be seen as the major land capability class of the community watershed. It covers an area of 267.8 ha (66.42%) with the listed major limiting factors. But class I is limited as compare to other classes of agriculturally suitable for annual crops. This class covers 4.61 ha area (1.14 %) which is dominated by gentle slope. In Deledel community watershed, this class is identified as the most suitable for annual crop production without any major limiting factors. Class VI (Suitable for perennial crops, grazing and some forestry) ranks second in the study area as it covers area about 97.5 ha (24.18%). Class VII (Suitable for forestry) has also a considerable coverage in the study area. It accounts an area of 32.19 ha (7.99%). Land not suitable for agriculture accounts an area of 5.72 ha (1.42%).