Soil and terrain database of the Republic of Malawi

This report describes the methodology that was used to compile the national Soil and Terrain (SOTER) database for the Republic of Malawi at scale 1:1,000,000. The GIS database provides generalized information on landform, parent material and soil conditions in digital format. The base information used to compile the database, including information on physiography, soils, agro-climate, land use and vegetation, was derived from the Land Resources Evaluation Project of the Food and Agriculture Organisation of the United Nations (Venema, 1990). Profile descriptions and soil analytical data were collected from Malawi’s Agricultural Development Divisions by the Maize Commodity Team; a digital database was created for the advisory and extension work of the Department of Agricultural Research in Chitedze, Central Region (Benson, Nambuzi, & Ligowe, 1999). This database was cleaned and incorporated into the Africa Soil Profiles Database (Leenaars, 2012). The soil map at scale 1:250,000 (Venema, 1990) provided the geographical basis for the SOTER map; representative soil profiles were mainly selected from the Africa Soil Profiles Database v1.0. All profiles are classified according to the World Reference Base for Soil Resources (IUSS Working Group WRB, 2007). For display purposes, all soil components are described according to the guidelines for small-scale map legends based on the World Reference Base for Soil Resources (IUSS Working Group WRB, 2010). To ensure consistency with earlier SOTER databases, the selected reference profiles are also characterised according to the Revised Legend of the Soil Map of the World (FAO, 1988). The database contains 231 unique SOTER units, comprising 298 terrain components and 534 soil components. The SOTER units are linked to 327 polygons in the geometric database. The soil components are characterized by 379 profiles. A total of 18 WRB Reference Soil Groups (RSG) were identified in Malawi. Lixisols are the dominant RSG, covering almost 26% of the country’s land surface, followed by Luvisols with 22% and Cambisols with 18%. The remaining RSGs cover less than 10% of the Malawi territory. Among these are Gleysols, Leptosols, Fluvisols, Ferralsols and Phaeozems that together cover some 35% of the land surface. The SOTER Malawi database can be used for broad-scale agro-environmental assessments such as estimation of soil organic carbon stocks, hydrological modelling, or crop modelling. The associated dataset is accessible via doi: 10.17027/isric-wdcsoils.20160002