District Intergrated Land Use Plan - Ngwaketse Land Board

CHAPTER 3
PHYSICAL ENVIRONMENT AND ITS COMPONENT SYSTEM OF RESOURCES
BASEMENT COMPLEX
3.3.7 The Basement Complex covers the southern part of the District in an area stretching from
Molopo farms through Metlobo and Tswaanyaneng to the southeastern part of the District.
The unit comprises of undifferentiated gneisses, migmatites and granites with minor
amphibolite and metasediments including banded iron formations. It also takes the form of
undifferentiated basic schists, greenstones with minor banded iron formation, cherts, acid
schists, marbles, acid gneisses and granites. The unit forms flat plains except banded
ironstones ridges. The lithologies in the unit are generally resistant to weathering.
INTRUSIVES
3.3.8 The eastern and northeastern part of the District is characterised by intrusive lithologies
mostly the Gaborone and Mmathethe granites. These are found in the southeastern part in
Pitsane, Mmathethe, from Digawana, throughout Molapowabojang, Moshupa to Jwaneng.
Some thin dykes occur throughout Southern District notably; northwest of Mabutsane and
south of Khakhea. Granites are generally moderately susceptible to weathering.
3.4 SOILS
3.4.1 Information on soils is important in land use planning as soils have different characteristics
that either render them suitable or unsuitable for specific purposes. Soil contains air, water
and organic materials that are crucial for it to support plant life. The natural functions of soil
revolve around fertility , underlying geology and depth, drainage and filtering capacity,
composition and texture, slope, available water holding capacity, pH categories
exchangeable cation capacity, electrical conductivity and exchangeable sodium percentage
categories. These soil characteristics determine the resource value of the soil fertility for
agriculture, forestry, plant life and its suitability for settlement development and as a
construction material.
3.4.2 Map 3.7 shows the major soil types found in the Southern District. Luvic Arenosols are the
most extensive covering 17632,9 km2 or 64.7 percent of the District, Haplic Lixisols are the
second most common (8.5 percent) while Ferralic Arenosols cover 7.2 percent of the
District. Maps 3.8 to 3.13 present detailed soil charcteristics of the District.
3.4.3 Leptosols take the form of Eutric Leptosols and Lithic Leptosols which vary from very
shallow to shallow soils with depth of less than 25cm to 50cm. Lithic Leptosols occur in the
hardveld while Eutric Leptosols are found in the transition between the hardveld and
sandveld south of the hardveld tongue. Lithic Leptosols are very shallow with depth of less
than 25cm. The topography associated with these soils ranges from rolling to hilly terrain
with slopes between 8 percent and in excess of 16 percent. Leptosols are well- drained to
somewhat excessively drained coarse textured sands, sandy loams and loamy sands.
Lithic Leptosols have a high pH of between 7.51 and 8.3 percent. Leptosols are classified
under the category of soils with moderate to low fertility.
3.4.4 Lixisols occur as Ferric Lixisols and Haplic Lixisols. They are found in the northeastern part
of the District around Pitseng, Moshupa and in the south, east of Mmathethe and in the
eastern part of Ngwaketse Agricultural District. The soils are associated with undulating to
hilly topography in the northeast and gently undulating to undulating topography in the
south. They are moderately deep between 50cm and 100cm in depth, are weld-drained in
Ngwaketse North and Ngwaketse Central agricultural district and range from moderate to
imperfectly well-drained in Ngwaketse South Agricultural district. The soils are coarse
textured sands, sandy loams and loamy sands in the north east. South of Mmathethe they
34 REPORT OF SURVEY