Soil degradation and erosion in the Little and Great Karoo have severely reduced farm productivity and water security, making many farms unviable. Water harvesting basins – small, shallow pits that collect rainwater – offer a promising solution for land restoration.
By Marise Schoonraad, journalist at African Farming and Landbouweekblad
Water harvesting basins have been introduced to some Karoo farms to reclaim unproductive soil on a large scale and break up the hardened topsoil. This practice involves creating shallow basins across degraded areas where no grass or plants can take root to retain water and soil.
The ongoing drought in parts of the Garden Route is forcing farmers off their land, as it is no longer viable to farm on this degraded soil in these dry areas, according to a media statement from the Garden Route Environmental Forum (GREF).
“Thousands of hectares are at stake,” says Cobus Meiring of the forum. This includes farms in the dry Eastern Cape and Southern Cape, as well as parts of the Karoo where the land has been overgrazed by goats, ostriches and sheep over many years.
Over the past 100 years, the soil surface and vegetation have been destroyed, causing the soil to harden and fertile topsoil to be washed away. As a result, many farms are no longer suitable for agricultural production.
“Various solutions have been explored. Removing livestock from the veld has not been sufficient and the problem has worsened because vegetation cannot regain a foothold in the hardened soil,” says Meiring.
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Labour-intensive But Effective
Although the process is labour-intensive, workers become skilled over time, improving efficiency.
The top layer of the soil is so hard that it must be broken open with a pickaxe to create a hole. Each basin is approximately the length and width of a shovel and as deep as the blade. A small embankment is built around the basin using the excavated soil.
Large areas – even hundreds of hectares – can be treated in this way.
According to Meiring, these basins serve two purposes:
- they allow vegetation to regain a foothold in the soil
- they prevent large volumes of water, especially during heavy rainstorms, from washing soil away, instead allowing it to infiltrate the ground
Supporting Soil and Vegetation Recovery
Windblown soil also settles in the basins, creating a more fertile layer that enables plants to establish more effectively, says Meiring.
Although thunderstorms and flooding in the Garden Route and Karoo bring significant relief to farmers and towns, these heavy rains also cause considerable damage to already degraded soil that cannot retain topsoil or runoff water. This results in increased erosion and further deterioration.
By implementing proactive measures such as water harvesting basins, rainfall can be utilised to make a meaningful difference to soil restoration and water security, the statement says.
Meiring emphasises that the most important step is to break the hardened soil crust so that water infiltration and root growth can occur below the surface. Farmers are now applying this practice with considerable success.
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Long-term Rehabilitation
This form of water retention is a simple and cost-effective method of restoring soil. However, it requires time, as the soil must recover and vegetation must re-establish.
Many farmers are planting spekboom (elephant bush) in the basins to assist with rehabilitation. Due to their root systems, spekboom plants stimulate growth and improve soil conditions. They also create a new microclimate by providing shade and trapping organic material on the surface.
“It is a process that takes time, as the soil needs to rest and recover,” says Meiring, who adds farmers’ feedback have been very positive. “It is a matter of waiting for rain – when the rain comes, plants begin to grow in the basins before long.”
Also read: Hollows that trap water and seeds aid in veld restoration
