‘Increased CO2 levels could benefit potato yields’

Potato yields are expected to increase 12% to 37% by 2050 due to increased carbon dioxide (CO ) levels 2 in the environment.

Prof Martin Steyn, associate professor at the University of Pretoria’s Department of Plant and Soil Sciences, said that as part of ongoing research which began in 1960, scientists had predicted that dryland potato regions in particular, such as the Western Cape’s Sandveld, would benefit from climate change.

Although warmer regions such as North West were unlikely to see as great an increase, these areas should see a slight yield increase.

“We’ve been simulating expected changes in temperature, rainfall and solar radiation,” Steyn said during Potatoes South Africa‘s transformation symposium held in Pretoria recently.

The studies showed that the temperature was likely to increase by 2°C on average by 2050, while rainfall would become less predictable.

“CO is the food that plants 2 need to produce biomass and that directly impacts yield. We expect the CO levels 2 [between] 1960 and 2050 to increase from 315 parts per million (ppm) to 550ppm.

“Because crops will take up air that’s richer in CO , they 2 will also need less water to extract the CO . Therefore, 2 water use will probably decrease over time as well.”

Research indicated that by 2050, potato plants could use 21% to 45% less water than what was needed in 1960.

Steyn added that farmers would need to adapt if they wanted to reap these benefits in future.

“We expect that potatoes will suffer more heat stress in summer, and farmers will have to mitigate this.”

Farmers also needed to prepare for an increase in the number of hot days, with these expected to increase three- or fourfold, Steyn said.

At the same time, farmers would have to keep in mind that frost would become a bigger problem in future. “New potato cultivars [are needed] to mitigate the [effects of the] extreme temperature changes that we can expect.”

Furthermore, planting dates would probably have to be moved forward to ensure that potatoes were planted at optimal times.

SUSAN MARAIS Aldrin Lawrence (second from right) of Limpopo was named Potatoes South Africa‘s Enterprise Development Farmer of the Year. With him are (from left): André du Toit (Go to Market manager, Bayer), Nomvula Xaba (transformation manager, Potatoes South Africa), Willie Jacobs (CEO, Potatoes South Africa), JF van der Merwe (chairperson, Potatoes South Africa), and Rodney Mbuyazi (transformation committee chairperson, Potatoes South Africa).