Biotechnology also helped bump up the expected corn yield to a record 4.78 tonnes per hectare, the attache said.
The country's Crop Estimates Committee expects the 2009/10 corn crop to reach 11.6 million tonnes despite a dry spell at the start of the growing season, the report said.
The rest of the season saw above-average rainfall, which will allow South Africa to export about 2 million tonnes of corn, the report said.
But plantings are likely to fall for the 2010/11 growing season.
"Two factors will contribute to lower plantings, namely, the expectation of full-scale El Nino conditions in the coming production season and the substantial drop in corn prices," the attache said.
El Nino is expected to bring much rain during the spring, but rainfall will taper off in the midsummer, possibly leading to a drought, the report said.
"Some commercial farmers may switch to sunflowers which are well adapted to hot and dry climates," the attache said.
Additionally, the price of corn is expected to drop, pushing more farmers to take on more profitable commodities.
Corn prices are currently about 30 percent below year ago levels, the report said.
Prices are falling due to "the strengthening of the Rand against the U.S. dollar in recent months, the excellent production season in South Africa which led to an oversupply and the expectations of a very good corn crop in the United States," the attache said.
Reuters