* China extends buying spree of U.S. soybeans
* USDA confirms soy export sale for 8th straight trading day
* Informa sees bigger U.S. corn, soy harvests than USDA (Adds closing prices, analyst quote)
By Tom Polansek
CHICAGO, Aug 5 (Reuters) - U.S. soybean futures jumped on Friday, extending a rebound from 3-1/2-month lows hit earlier this week, as strong export demand offset supply pressure linked to bumper harvest prospects.
Wheat futures also climbed while corn crept higher as the grain markets consolidated after falling to 10-year and near two-year lows, respectively, this week against a backdrop of ample supplies.
Soybean futures were the leader in the markets, traders said, after the U.S. Department of Agriculture (USDA) reported that exporters had struck deals to sell 498,000 tonnes of U.S. soybeans to top-importer China for delivery in the marketing year that starts on Sept. 1.
It was the eighth consecutive trading day in which the USDA confirmed a soybean sale to China or "unknown destinations," bringing total volumes for that period to 2.8 million tonnes.
Traders expect even more business.
"The U.S. is in the driver's seat for demand until the next South American crop is available after the first of the year," said Tomm Pfitzenmaier, analyst for Summit Commodity Brokerage in Iowa.
Most actively traded soybean futures on the Chicago Board Of Trade ended up 1.9 percent at $9.74-1/2 a bushel, its highest close in a week.
The most active wheat contract surged 3.2 percent to $4.16 a bushel after sinking 1.7 percent in the previous session. Most-active corn rose 1 percent to $3.34-1/4 a bushel after losing 1.2 percent on Thursday.
Corn and soybean futures have been under pressure recently from favorable weather forecasts for the U.S. Midwest, boosting expectations for massive harvests later this year.
Analytical firm Informa Economics on Friday predicted the autumn corn harvest will reach 14.694 billion bushels, with a yield of 169.8 bushels per acre. The company pegged the soybean harvest at 3.958 billion bushels, with a yield of 47.7 bushels per acre.
That topped the USDA, which in July estimated the corn crop at 14.540 billion bushels, with a yield of 168.0 bushels per acre, and the soybean harvest at 3.880 billion bushels and a yield of 46.7 bushels.
"The Chinese continue to book U.S. soybean cargos at a torrid pace," said Kevin Van Trump, chief executive of Missouri-based agricultural consultancy Farm Direction.
However, the deals are "getting very little respect in the markets right now because of all the hype and talk surrounding record acreage and likely record yields here in the U.S.," he said.
The USDA is set to update its crop estimates next week.
Additional reporting by Gus Trompiz in Paris and Colin Packham in Sydney; Editing by Marguerita Choy and Richard Chang