(Updates with closing prices, adds details on Brazil harvest)
CHICAGO, Jan 19 (Reuters) - U.S. soybean futures rose for the fifth straight day on Friday, hitting their highest in 5-1/2 weeks as concerns about crop development in South America fuelled buying, traders said.
Parched soils in Argentina have underpinned prices throughout the week.
"Dryness in Argentina has provided enough fuel for soybean prices to find footing with multi-day gains this week," Ben Potter of Farm Futures said in a note to clients.
Signs of strong export demand also lent support to soybeans which notched their biggest weekly gain in three months. Corn futures also rose on the back of better-than-expected data from the U.S. government.
Wheat was trading in negative territory, weighed down by profit taking and technical sales following two straight days of gains.
Chicago Board of Trade March soybean futures settled up 4-1/4 cents at $9.77-1/4 a bushel. Soybean futures rose 1.5 percent this week.
The U.S. Agriculture Department on Friday said weekly export sales of soybeans totalled 1.528 million tonnes, topping market forecasts that ranged from 800,000 to 1.4 million tonnes.
A slow start to harvest in Brazil could keep export interest focused on the United States for longer than usual. Brazil's 2017/18 soybean crop harvest is lagging last year's pace and the long-term average for this time of the year, which will result in a sharp reduction in the amount of soy available in the market by the end of January.
CBOT March corn futures were 1 cent higher at $3.52-1/2 while CBOT March soft red winter wheat was down 2-1/2 cents at $4.22-3/4 a bushel.
Weekly corn export sales of 1.891 million tonnes were well above analysts' estimates while export sales of wheat were just 190,500 tonnes, below a range of market forecasts.
For the week, CBOT corn rose 1.8 percent while CBOT soft red winter wheat was up 0.7 percent.
Persistent dryness in Argentina has raised concern about harvest prospects in the world's third-largest soybean producer.
"It's certainly a concern, given that Argentina is the biggest soymeal exporter and we see soymeal prices leading the soy complex," said Graydon Chong, senior commodity analyst at Rabobank.
CBOT soymeal hit its highest since Dec. 11 on Friday.
The Buenos Aires Grain Exchange could reduce its 2017/18 soybean planting area estimate further after sowing delays caused by dry weather in northwestern Argentina, it said on Thursday. (Additional reporting by Naveen Thukral in Singapore and Gus Trompiz in Paris; Editing by Tom Brown and James Dalgleish)