About 80% of the maize in the summer rainfall areas had been planted after the optimum planting period in the respective regions and was very young and particular vulnerable to the extreme heat and dust storms common in the Free State and North West.
The optimum planting period for maize in the eastern summer grain production area expired at the end of November 2015 and the planting period for maize in the western summer grain production area expired on 5 January 2016.
Johan van den Berg, Santam Agriculture weather expert in the meantime said the large tracts if fallow lands and the lack of natural vegetation because of the drought, contributed to the development of dust storms.
In normal rainfall years the veld would have been covered by now and the grain lands covered by crops. “Wind is not uncommon by this time of year, but huge dust storms are. Remember, February and March are high rainfall month traditionally” he said.
The high temperatures, he added, were the result of a high pressure system caused by the El Niño system. “It seems as if the El Niño system is weakening at a slower rate than expected. The system is now, in February 2016, only 20% weaker than what it was at its peak at the end of November 2015.”
The water consumption rate of maize obviously increases markedly in times of drought and heat, said ARC researcher Dr Andre Nel. Higher heat units result in rapid development, but in times of extreme heat plant development could be severely compromised because of heat stress.
Coupled with a lack of moisture poor yields are virtually inevitable in the 2015/2016 production season. “The situation could be exacerbated further if we experience early frosts,” said Nel.