Surface Irrigation Suitability Assessment of the Soils of Almanaqil Ridge, Gezira State, Sudan

The main objective of this study was to spatially evaluate land suitability for surface irrigation in the Almanaqil Ridge, Gezira State, Sudan, on an area about 220.000 acers. The evaluation was based on FAO (1985) guidelines and the method proposed by Sys et al., 1991 (PART I, II, and III). Hundred check (auger) sites and 16 profiles were studied. The area was divided into 3 mapping units. The units are classified according to the American System (Keys to Soil Taxonomy, 2010) in the fallowing families: Fine loamy, mixed, isohyperthermic, TypicHaplustepts (unit1), Fine, mont, superactive, Isohyperthermic, VerticHaplocambids (unit2) and Fine, mont, superactive, isohyperthermic, TypicHaploustert (unit3). The 30 m spatial resolution Digital Elevation Model was used to generate slope by using Spatial Analyst Tool Surface Slope in ArcGIS 9.3 environment. Land characteristics used as criteria were slope class, texture, soil depth, calcium carbonate status, salinity & sodicity and drainage. The irrigation suitability map was compiled by matching between reclassified Land characteristics with irrigation land use requirements (LURs) using GIS tools. The results showed that units 2 and 3 are slightly suitable. This could be due to limitation of the clay texture (vertisolic) and drainage (low infiltration rate) while mapping unit 1 was suitable. The result can assist decision makers in ensuring that lands are used according to their suitability.