2.2 Agriculture, forrestry and alien plants

Social sciences:

Geography

Grade 8

Natural resources

Module 8

Agriculture, forrestry and alien invaders

Agriculture

The greatest damage that humans inflict on the earth – and by implication, the greatest threat that humanity poses to its own future survival – is through the practice of agriculture. Huge areas of the planet’s natural terrestrial ecosystems have already been destroyed and replaced with artificial agricultural systems, greatly reducing or even negating the ability of the land to control and influence its own climate and chemistry.

Of South Africa’s surface area of some 120 million hectares, about 85 per cent is used for agriculture and forestry. Only 45 per cent of the country receives more than 500 mm rain annually – the generally accepted minimum for dryland crop production – and only 12 per cent is suitable for cultivation. The rest is mainly natural veld used for grazing.

Because of the lack of suitable planning in the past and gross over subsidisation – often to win political favour – much prime arable land has been irrevocably lost to urbanisation, mining (particularly on the Witwatersrand and in Mpumalanga) and other activities. Also, injudicious management and cultivation of crops not ecologically suited to conditions have caused widespread degradation in the form of soil erosion and desertification. Annual soil losses, mostly through poor land husbandry practices, are estimated at between 300 and 400 million tonnes annually.

The question of existing land ownership in agriculture is being addressed as a matter of urgency by the Government of National Unity. Before the 1994 elections, an estimated 50 000 white farmers – many of them heavily subsidised for political reasons and extensively in debt to an amount of R14 billion – owned some 85 million hectares, of which about 14,3 million were arable. The 700 000 black farmers in the former “homeland” areas had access to only some 15 million hectares, of which only 2,3 million were arable.

Activity 1:

To identify the poor management of agricultural land and suggest precautionary measures

[lo 3.3]

1. Underline the correct words. Explain your choice.

• Livestock must be decreased/increased to remain within the capacity of the land.

• The simultaneous cultivation of crops and the keeping of livestock must be encouraged/discouraged .

2. Why is it necessary that the use of fertilizers, insecticides and weed killers should be strictly controlled? Give your opinion.

3. In what respect does urbanisation contribute to the destruction of agricultural land?

Forestry

Forests are an integral part of Earth’s life-support systems, playing a crucial role in regulating the atmosphere and climate through their ability to store carbon and drive local hydrological cycles. They protect soils from excessive erosion, regulate run-off and reduce the effect of floods and consequently silt loads in rivers. Natural forests are usually highly diverse ecosystems, supporting millions of species and providing human beings with a wealth of benefits. They are also an important part of the resource base for tourism and recreation, and have an inestimable cultural value as a source of beauty, contemplation and inspiration that finds expression in art, music, literature, dance and religion.