Estimated reading time: 6 minutes
Many producers in the Kalahari and the Northern Cape have been hard hit by severe drought conditions over the past seven years, and some were on the verge of throwing in the towel. This year, large parts of the country’s agricultural regions received summer rain. Several farms received rain shortly before winter, which carried the veld through the difficult months.
The origin of our rain
For the next rain season there seems to be a silver lining around the dark cloud. According to Johan van den Berg, well-known meteorologist who understands the intricacies of farming, indications since last year have shown that we are entering a wetter cycle. He says temperatures in the Indian Ocean have started to cool and we can expect a La Niña phase, which is very positive for rainfall in Southern Africa.
According to Johan, we could expect rainfall from August to November this year to be slightly below average, but it should improve significantly from November. In the summer rainfall regions, where approximately 70% of annual rainfall occurs between November and April, exceptionally good rains are being forecast, although its distribution over time often determines agricultural conditions.
Figure 1 illustrates the probability of average rainfall exceeding the norm between September and November 2021, and Figure 2 the probability of rainfall from December 2021 to January 2022.
Cycles and climate change
Agriculturalist Dr Louis du Pisani said on occasion that producers, especially those farming in the arid regions known for regular droughts, should do their yearly planning as if a drought is imminent. Johan adds that it is essential to take note of nature’s cycles and plan ahead for dry and wet years.
Rain cycles and temperatures go hand in hand. Over the years, it frequently happened that above-average hot cycles were followed by cold years, which is related to past droughts. Global warming is a reality. The earth’s temperatures have been rising sharply since the 1980s and it is estimated that nowadays it is more than 1°C hotter than a century ago.
Yet climate change manifests in several ways. Daytime temperatures in the Northern Cape rise over time, but night or minimum temperatures show a decline, especially in the winter months, with more intense winters over the past decade or so. The differences between day and night temperatures are also getting bigger.
“The planet has started building up heat in the last 150 years, and since the 1980s oceans have started getting warmer. This has given rise to an increased frequency of cyclones, especially near the equator,” he says.
Length of droughts and wet years
Johan studied the rainfall figures for Askham in the Northern Cape. Since 1915, producers have had to face several droughts (Figure 3). He recorded the following drought lengths (duration):
- A nine-year drought (1959 to 1967).
- Two eight-year droughts (1926 to 1933, 1981 to 1988).
- A five-year drought (1945 to 1949).
- Two four-year droughts (1952 to 1955, 1970 to 1973).
- Seven two-year droughts.
- Thirteen one-year droughts.
The duration of the wetter years since 1915 was recorded as follows:
- One nine-year period (1917 to 1925).
- One eight-year period (1911 to 1918).
- One seven-year period (1974 to 1980).
- Two six-year periods (1989 to 1994, 1997 to 2002).
- Two five-year periods (1940 to 1944, 2005 to 2009).
- Thirteen one-year periods.
The factors behind a drought
Johan says global warming is a given, but that not everything can be laid at its door. There are different definitions of droughts, depending on your point of view. Meteorological droughts are marked by below-average rainfall. For agricultural producers there are agricultural droughts, which occur when less than favourable amounts of rain fall in the growing season.
There is also a hydrological drought – when surface water is insufficient. Reasonable amounts of rain may fall, but the runoff may not be sufficient to fill dams. A socio-economic drought is when producers can no longer farm sustainably. This, in turn, has a major impact on water and food security.
Several factors need to be considered. For some, nothing can be done – it simply needs to be managed. These include climate change, demographic changes and changing ecosystems. There are also certain factors that can aggravate a drought, but which can be remedied. Being prepared for weather changes and not being overly optimistic in their expectations will play in producers’ favour. Also be careful not to overgraze the veld, keep your living cost low and understand the risks on your farm.
Managing dry and wet years
“Farmers are under a lot of pressure to produce more and farm sustainably at the same time. They have to go bigger, realise higher yields and employ new technology. This exacerbates the demands placed on farming enterprises. The slightest change in climate can throw any producer’s planning into disarray. For these farmers, the drought may seem drier than it really is. Timeous plans must be made with a view to climate change and rainfall,” he explains.
A study of rainfall patterns in the Upper Karoo by Hannes Gerber of the Northern Cape Department of Agriculture shows that this area, which is characterised by frequent droughts, has in fact received more rain in the past eight decades than ever before. Rainfall during the last 30 years has been higher than in the period prior to 1989.
Hannes concludes that producers in these areas should not be complacent, but rather use every opportunity to prepare for the next drought. “Producers in arid regions have not only learned to adapt to difficult conditions, but also to expand when conditions improve.
“It is important that farmers understand weather patterns and cycles, and adapt their management practices to the circumstances. This can be done by farming adapted livestock breeds, reducing numbers in time so that they can survive on the available veld, and practicing sustainable grazing management. All droughts are followed by wet seasons and, in many cases, excessively wet seasons,” he says.
Johan agrees that producers must be vigilant. Plans must be made well in advance for the drier cycles that often follow a good, wet year.
He is positive about the year to come, but warns that rain is not the only factor needed for sustainable farming. Good rains also pose certain disadvantages that producers have to bear in mind. Pests, plagues and unexpected animal diseases can easily get in the way and must be managed properly and preventively.
For enquiries, contact Johan van den Berg on 082 374 4692 or email wjvandenberg1959gmail.com.