Die gronde van die Karoo

[摘要] ENGLISH ABSTRACT: Soil information pertaining to one of the most extensive arid andsemi-arid areas of South Africa is limited. This area, known asthe Karoo, comprises 36 million hectares or 32% of the surfacearea of South Africa. The purpose of this study was to gather asmuch information as was possible regarding the distribution,morphology, classification, physical, chemical and fertilitystatus of the soils of this area.The pedosystem concept was used to identify and demarcate theterrain and soils of this study area. This assumes that a fairdegree of interdependence exists between the environmentalcharacteristics, terrain morphology and the soil. From this ageneral map (scale 1: 1 000 000) of the Karoo was produced. Thisillustrates broad soil patterns, while topsoil texture classesand underlying materials can easily be read from the map. Inaddition, terrain characteristics (i.e. percentage level land andrelief) are also given.For the interpretation of soil and terrain characteristics it wasnecessary to define a small number of natural regions of theKaroo. In these regions the natural resources of soil, terrainand climate are strongly interdependent. They have been calledbroad physiographical regions. Twenty such regions have beenidentified in the Karoo. For each broad physiographical region adescription is given of the nature and extent of the terraintogether with the distribution of the soils with their morphology,classification, physical and chemical characteristics andfertility status.The soils of the Karoo can conveniently be arranged into seventeenbroad soil patterns. It was clear that shallow calcareouslithosols and red apedal soils with a high base saturation occupythe largest area of the Karoo. The red soils usually have sandy topsoils (A horizon) while the clay content of the calcareouslithosols is slightly higher varying from 6- 15%. The deep,weakly structured soils which are associated with unconsolidateddeposits and which should have a high potential for irrigation,occupy ca. 1 million hectares and occur mostly in the central ,northern and eastern parts of the Karoo. Approximately 22 millionhectares (60%) of the soils of the Karoo are stony and a further14% are covered by desert pavement.

[发布机构] Stellenbosch University