Land Degradation

Author: Dr Eureta Rosenberg

What is it?

The experts disagree on how to define land degradation and associated processes such as desertification, but as an issue it is not difficult to understand. Land degradation occurs when the economic and biological productivity of land is lost, primarily through human activities. This can happen, for example, when:

• Fertile soils erode away,
• Indigenous trees are removed,
• Alien plants invade an area,
• Farm land is used for housing,
• Soils become salty through poor irrigation, or
• Soils are degraded by acid pollution and heavy metal contamination.

The loss of productive land obviously affects farming and rural communities. As the land degrades, more fertiliser, machinery and supplementary feeds are needed and the cost of production increases. Small-scale, subsistence farmers are often unable to meet extra costs and even large-scale, commercial farmers can find that farming becomes impossible. As a result, farm workers and others may be forced to move to towns and cities, only to face unemployment and poverty.

So land degradation also affects our urban areas, through spreading informal settlements and rising food prices. Water also becomes more expensive as soil erosion makes rivers muddy and causes dams to fill up with silt, adding to the costs of water purification and storage.

How big is the problem?
After looking at the vast array of food on display in a South African supermarket it may be hard to imagine that food security could be an issue. However, many households struggle to feed themselves and in parts of the country, notably the Eastern Cape, children suffer from malnutrition. The Earth Policy Institute predicts that, globally, insecure food supplies will become an even more a widespread source of conflict and hardship in the future.

Only 13.5% of South Africa’s land surface area is considered arable, or suitable for food production. Every year an estimated 34 000 hectares of farmland is converted for other purposes to other uses such as urban expansion. At this rate, by the year 2050 the experts predict that there will be no more than 0.2 hectares per person available on which to produce food in South Africa. This is considerably less than international norms. Food imports are expensive and, like other environmental problems, they hit the poorest people hardest.

While it is difficult to estimate the extent of the problem of land degradation, there is no doubt that people around the world are suffering from its effects. The term ‘environmental refugees’ has been coined to refer to people who have had to abandon their homes because, for various reasons, the land has lost its capacity to sustain them.

Globally, a staggering 70% of all drylands (or non-tropical regions) are already classified as degraded. This represents 14% of the earth’s land surface area. Africa may be the worst affected continent, as 73% of its agricultural drylands are thought to be degraded. The number of people affected is vast, for it is estimated that more than about 70% of Africa’s 500 million people depend directly on the environment for their livelihoods.

The United Nations Conference on Environment and Development drew up a Convention to Combat Desertification to address the problem of land degradation. As a signatory, South Africa is required to develop a National Action Programme to Combat Desertification and commissioned a survey of the extent and causes of land degradation in the country. The survey results are summarised in a user-friendly book called Nature Divided: Land Degradation in South Africa by Hoffman and Ashwell. Of the many aspects of land degradation it covers, we can note only a few.

What does it involve?
Desertification is one aspect of land degradation. It is related to veld degradation (when rangelands lose their vegetation cover through over-grazing or inappropriate fires), deforestation and soil erosion.

Deforestation refers to the loss of trees. South Africa’s trees are heavily used for construction, herbal medicine and fuel. Up to 99% of rural households use firewood for energy and, despite electrification projects, about 38% of township residents also use firewood. Shortages are already being experienced and it is estimated that, if unchecked, and at the current rate of harvesting, trees will have disappeared from communal areas within 20 years. While the number of people in rural villages plays a role in deforestation, urban demand for wood and traditional medicine also contributes to the problem. Deforestation makes life harder for rural people, destroys the habitats of numerous creatures and contributes to soil depletion and erosion.

Soil erosion causes the loss of the fertile layer of topsoil in which food crops can grow. Through factors such as reduced plant cover, topsoil is removed by wind and water. The eroded soil can cause eutrophication of dams and rivers and can harm the marine environment. Environmental issues that face us today are usually the result of complex chain reactions! They always have an economic impact. In this case, the farmer has to enrich his depleted soils with fertilisers – costing agriculture an estimated R1.5 billion per year.

The loss of soil quality is another contributing factor to land degradation, through pollution with heavy metals and acid from mines and power stations. Again, the loss of soil productivity is expensive; for example, it costs about R25 million to neutralise the effects of acid rain in Mpumalanga.

Invading alien plants are plants that are not indigenous to South Africa but which grow so prolifically that they threaten indigenous plants and decrease the land’s biological productivity. Of the 161 classified invaders, syringa, black wattle, eucalyptus, lantana, rooikrans and Port Jackson are the most common, covering an area about the size of Gauteng. They spread or ‘invade’ quickly, partly because the local environment has few means of keeping them in check. As they do so, they push out indigenous plants, reducing biodiversity. In addition, invading alien plants contribute to soil erosion, reduce grazing areas and reduce the capacity of indigenous plants to reproduce. Some alien plants burn more easily and intensely than the indigenous vegetation, thus increasing the risk level and damage caused by fire. Some also use far more water than indigenous plants; for instance, woody aliens use about 3 300 cubic litres per year. In the dry interior, mesquite (suidwesdoring) threatens precious groundwater supplies. Alien trees on the Western Cape coastal mountains and lowlands may reduce the mean annual run-off by one third. The need to build new dams in ecologically sensitive areas could be substantially reduced if thirsty alien species were removed.

It is interesting to note that many plants now classified as invasive were originally brought to South Africa as solutions to problems! They were imported to provide fodder, to stabilise driftsands, or to supply the leather and mining industries. Another example of a technical solution causing unforeseen problems is the use of inappropriate irrigation systems on some commercial farms. Not only is inappropriate irrigation wasteful it can also cause waterlogging and salinisation. Many agricultural lands along the Fish River have been rendered useless by poor irrigation. Potential ‘quick-fixes’ should be considered very carefully, as they can create further problems in the long-term. We should bear this in mind when coming up with strategies to tackle land degradation.

What can be done?
Solutions must take into account the history of land degradation. Political practices of moving people from where they were settled into reserves and homelands contributed to the pattern of land degradation in South Africa. In former homeland areas such as Ciskei and Transkei the productivity of the land has been reduced to such an extent that most residents are unable to feed their families, let alone make a small profit from the land.

Black South Africans were not always impoverished as farmers. In the 1800s Basotho farmers out-competed European settlers, producing more grain more cheaply. Not only did they feed themselves, they also exported sheep, horses, grain and wool to the mines and the Cape Colony. But the government, being concerned about competition with white farmers, restricted the Basotho’s access to markets and land, and forced them into the barren mountains of Lesotho. Black people remaining in what became the Republic of South Africa were eventually confined to only 13% of the land. ‘Over-crowding’ in the homelands was blamed for land degradation. Ironically, ‘under-farming’ may have played a bigger role. The migrant labour system resulted in few decision-makers and able-bodied people being available to do labour-intensive farm work. Furthermore, there was very little money to invest in farming. Farming around the world requires subsidies and, unlike their counterparts in the Republic, homeland farmers had no government support or access to credit.

As a result of the social and environmental engineering of apartheid, people were reluctant to respond to government schemes for improving the land. An impression developed that black people did not care for the land. Yet, even today, farmers in Venda spend hours and months, with little more than their own labour to draw on, building terraces to combat erosion on the fertile slopes of the Soutpansberg mountains.

Solutions to land degradation problems should take account of the conservation methods that some land users already practise. VaVenda farmers’ traditional soil conservation methods include contour ploughing, stone walls and grass strips. Large-scale commercial farmers in the Karoo achieve considerable success with ‘holistic land management’ methods.

These are just two of the initiatives that we can draw on to develop flexible strategies for improving the quality of the land and encouraging sustainable land use throughout this country of diverse environments and cultures.