Brazil will reap a record grain harvest of 163.3 million tons this year, a gain of two per cent over 2011, the IBGE statistics agency says.
The IBGE's latest forecast, based on July data, is 1.6 per cent higher than the previous projection.
The upward revision is due mainly to improved prospects for the maize crop, which is now expected to come in at 71.5 million tons, up 27 per cent from last year.
Despite weather-related losses in the first half of 2012, the IBGE expects a bumper maize harvest thanks to improving environmental conditions and an expansion of 9.6 per cent in land under cultivation.
"These numbers reflect the good prices the product is finding in the market, which makes the growers opt for cultivation and increases investment in technology," the IBGE said on Thursday.
Global maize prices are rising due to crop losses in drought-stricken areas of the United States.
The soy harvest, however, is expect to fall 12.2 per cent to 65.8 million tons because of unfavourable weather, while the rice crop is projected to shrink by 14.9 per cent from last year, mainly as a result of less land under cultivation.
Maize, soy and rice together account for 91 per cent of crop output in Brazil, one of the world's leading agricultural producers and exporters.
Half of the 26 crops tracked by the IBGE are forecast to enjoy bigger harvests in 2012, including cotton, up 4.9 per cent; oats, 13.5 per cent; and barley, gaining 15.6 per cent.
The IBGE is projecting declines in output of sugarcane and wheat, among other products.