What is Soil Science?

Soil Science is the science that treats soil as a natural resource. Through first-rate instruction, an extensive research programme and active participation with the agricultural and farming communities information is provided on the origins, classification, geographical diversity and utilisation of the country's soil; the promotion of sustainable production of plants to supply the food and fibre requirements of the population; and measures to combat deterioration of the environment to ensure healthy living environments for the population and wildlife.

What does the soil scientist do?

Soil scientists can specialise in the various subdivisions of the subject. However, to be a good specialist a person should have a good insight into the subject as a whole.   Firstly, there are the group of soil scientists who do soil surveys. These people spend a great proportion of their time in the field. They study soils by means of profile pit observations or by drilling with mechanical augers. Morphological characteristics such as depth, colour, drainage and texture are used to identify and classify different soil types. They are then mapped on aerial photographs or other base maps.

Thereafter soil samples are taken to the laboratory and subjected to physical and chemical analyses. There the soil scientist uses interesting techniques and apparatus such as X-ray diffractometers, stereoscopes, microscopes and atomic absorption spectrophotometers. In this manner soil types are identified and soil maps compiled.

By taking all these pieces of information into consideration the production capability or potential of each soil type and its most profitable use is determined. This information and these maps are used for planning irrigation, farm management, regional management, for urban planning, planning of roads, pipelines, power lines, etc. Soil maps can also be used by the security forces for conventional warfare.  Where problems exist they are investigated by other soil specialists. The soil physicist and soil hydrologist, for example, study and research problems such as water management, water movement in the soils, drainage, soil-air permeability, formation of ploughsoles, swelling and shrinkage (which cause houses and roads to crack).

The soil chemist and soil fertility specialist study problems such as plant nutrient deficiencies or availability for plant uptake, fixation or leaching (washing out) of plant nutrient elements and fertilisers with the aid of field trials and by using techniques such as radioactive fertilisers. This knowledge is used to compile the most effective fertilisation programmes.

Soil biologists study the transformations in the soil brought about by micro-organisms, including processes such as the formation of humus and the fixation of atmospheric nitrogen by nodular bacteria on the roots of leguminous plants.

What is presented in Soil Science courses?

Soil Science comprises a study of the following:

Soil genesis - the interaction of climate, biota and topography on different rock to form different soil in time; the spatial variation of soil properties in soil profiles.
Soil survey and evaluation - identification of soil properties, soil classification, soil evaluation and land-use.
Soil chemistry - the study of all the various chemical reactions and processes that occur in soils, soil analysing methods, soil salinity and soil acidity.
Soil fertility and fertilisation science - the reactions of the various nutrient elements such as nitrogen, potassium, phosphorus, etc; the availability and supply thereof to the soil-plant system; production and characteristics of fertilisers and the influence thereof on plant growth; interpretation of soil analysis data.
Soil physics and hydrology - the physical characteristics of soils such as soil consistency, thermal characteristics, air movement, etc: the hydrological characteristics such as water movement through soils, irrigation practices, etc.
Soil Biology - the biological processes such as the decomposition of organic material and the synthesis of humus, etc.