An Affordable Way To Fix Poor Drainage

Slow water seepage in a field can adversely affect yield, profit, and the land’s long-term sustainability. Lindi Botha spoke to two experts about how to identify and rectify drainage problems.

- Lindi Botha

FAST FACTS

Poor drainage on farmlands can drastically reduce crop yield.

These issues are often overlooked and their impact underestimated, as the focus is generally placed on enhancing nutrient levels in the soil to boost yield.

Today, thanks to new technology, solving drainage problems has become easier and cheaper.

In a water-stressed country such as South Africa, it’s difficult to imagine any farmer complaining about having too much water. However, across the country’s irrigation schemes, lands are deteriorating due to waterlogging caused by years of incorrect water and soil management.

The source of the water may be long-term irrigation, percolation from precipitation, or the movement of water from high-lying areas.

Globally, 500 000ha of agricultural land are falling out of production every year due to poor drainage. It is estimated that in South Africa, 240 000ha are affected by rising water tables and salinization, and the problems appear to be growing.

Drainage problems in South Africa occur mainly in the following areas:

• Along the Orange River in the Northern Cape, especially Vaalharts, Douglas and Upington;

• The winter rainfall areas of Robertson, Worcester, Swellendam, Ceres, and Wellington in the Western Cape;

• Pongola and Nkwalini in KwaZulu-Natal;

• The Gamtoos Valley, Sundays River Valley, and Fish River Valley in the Eastern Cape;

• The Loskop and Hartbeespoort Dam irrigation schemes in Limpopo;

• Mainly where irrigation is concentrated.