Uncertainty over Western Cape wheat cultivation conditions for the next few years

There is a strong possibility that, in the next few years, parts of the Western Cape’s wheat-growingareas may be affected by poor rainfall conditions, which could lead to poorer harvests.

According to Johan van den Berg, agricultural meteorologist at Santam Agriculture, rain fell in thelast few years at the right time which, on the whole, resulted in good wheat production over themajority of the Western Cape. However, there are real indications that in the coming few years, aspart of a dry cycle, poorer rainfall may occur during the active growing season, especially in theSouthern Cape.

“During the past few years, average to above-average rainfall fell during the growing season in theWestern Cape wheat district, although in 2015 the Swartland area of the Western Cape had below-average rainfall,” said Van den Berg.The Swartland’s wheat harvest fell to 368 000 tonnes in 2015, in comparison to harvests of 593000 tonnes in 2014 and 558 893 tonnes in 2013.

Although the Swartland district had average rainfall in 2016, Van den Berg explained that verygood rain fell in September, which contributed to a leap to 644 000 tonnes in the area’s harvest forthe year.

September is a critical rainfall month for Western Cape wheat, as the plants are then in theirreproduction phase and drought-induced stress can inflict great damage.Neel Rust, chief operating officer of Laeveld Agrochem, explained that berg winds, which normallycome in August, can also have a negative effect on the wheat harvest. The effects of cold frontswhich move across the country, together with the start of the warmer summer temperatures, oftencause the dry land/berg winds.

Wheat is predominantly cultivated in the Western Cape’s Swartland and Rûens growing areas, butalso in the Southern Cape, as far as Mossel Bay.

According to Van den Berg, the climatic cyclical effect over the long-term has the greatest effect onthe average rainfall variance and, up until now, climate change has played a lesser role.

The attached graphs show the rainfall variance of the long-term, average rainfall (expressed as apercentage of the long-term rainfall average) for the critical times of the wheat growing season,from June to September, for the Rûens and Swartland areas.

Van den Berg is of the opinion that the expected weaker rainfall situation over the next few yearswill be more concentrated in the Southern Cape than the Swartland production areas.

The Western Cape is the biggest contributor to the country’s wheat harvest. The National CropEstimates Committee’s latest figures show that the Western Cape harvested 1 098 200 tonnes ofwheat in 2016. The country’s total harvest estimate for 2016 stood at 1 910 000 tonnes.

According to Rust, South Africa is a net importer of wheat, which means that the country mustimport wheat to fulfil the market’s demand. At the moment, the yearly demand stands at more thanthree million tonnes.

Background informationThe sowing of wheat in the Western Cape occurs until the end of May, and it is imperative that rainfalls before mid-June, but preferably before the end of May, so that the new plants can emerge and establish.

Rain must also fall in the vegetative part of the growth season, from June to August, but it is not ascritical as in September.Just before and during harvesting, from October until the first part of November, rain mustpreferably not fall, as even a little rain, together with overcast skies, can cause much damage tothe quality of the crop.