Although further rain is expected in the northern and eastern parts of South Africa over the next two weeks, the chances of widespread heavy rainfall remain slim.

By Alani Janeke, senior journalist at African Farming and Landbouweekblad

Summer grain farmers, particularly in the central and western parts of the country, urgently need rain to achieve good harvests. While more rain is forecast for the eastern and northern regions over the next two weeks, very heavy rainfall has already occurred in parts of these areas, especially in the far north.

According to independent agricultural meteorologist Johan van den Berg, a band of heavy rainfall may extend for at least the next two weeks over Angola, Zambia, the far northern parts of Botswana, Zimbabwe, central to northern Mozambique, the Mozambique Channel and Madagascar.

“Over the rest of South Africa, as well as Namibia and Botswana, little rain is expected until at least mid-February,” says Van den Berg.

He adds that rainfall will occur in patches and streaks. While some smaller areas may receive good rainfall, precipitation over most regions is expected to be very light.

‘Make-or-break’ period for summer grains

January to March is regarded as the “make-or-break period” for summer grain crops. If hot and dry conditions persist over the next two to three weeks, damage to summer grain crops could begin to occur.

Van den Berg says there should be enough groundwater to prevent complete crop failure, but this applies only to soils with good water-retention capacity. Shallow soils and soils with a high clay content may begin to suffer permanent and more severe damage.

“High plant densities can accelerate drought damage because more leaves are exposed to the atmosphere, increasing transpiration and water extraction,” he explains.

Also read: Summer grain conditions: Some farmers pray for sunshine; others for rain

Risk of a disastrous drought for veld production

January to March is also the period during which approximately 60% of annual veld production takes place. Grazing conditions in parts of the Eastern Cape, southern Northern Cape and western Free State are already very poor due to limited rainfall over the past six to eight months.

“If rainfall over the next two to three months is also poor, it could trigger a disastrous drought cycle that may continue into winter, spring and the early part of the next summer,” says Van den Berg.

He emphasises that producers in these areas should continuously review management decisions to align livestock numbers and types with available feed resources.

Also read: Parts of the Free State last experienced this much rain in 1934

Very high temperatures forecast

Very high temperatures of between 30°C and 40°C, or even higher, are forecast for the western parts of the Western Cape over the next two to three weeks. Temperatures of up to 35°C may also occur in the Overberg and Southern Cape.

“Scorching conditions above 40°C could persist for extended periods – from seven to ten days – over the Northern Cape, southern Namibia and southwestern Botswana,” says Van den Berg.

These extremely hot conditions are, however, favourable for the grape and raisin industries in both the Northern and Western Cape.

Limited rainfall for winter rainfall areas

Rainfall over parts of the Garden Route last week may help replenish dams in areas such as George and Knysna, but the overall water situation in the Garden Route and Southern Cape remains critical.

Approximately 50mm of rain was recorded in the George area, 70mm in Knysna and 25mm in Mossel Bay. At Avontuur in the Langkloof, only 15mm was measured, while less than 5mm fell at Joubertina and further east.

“The water situation in the Langkloof is becoming increasingly critical, as most farm dams are at very low levels and will not have sufficient water to last the production season,” says Van den Berg. “Much more rain is needed to avert a disaster.”

Across most of the winter rainfall region, the likelihood of rain over the next two to three weeks remains low. Light rainfall of less than 15mm may occur between 28 January and 1 February in the George area.

“In the longer term, most forecasts remain unfavourable for meaningful rainfall until at least May in both the Western and Eastern Cape,” Van den Berg concludes.