--The soybean market has jumped 12% since Jan. 30

--Industry concerned about demand stripping supplies down to bare minimums this year and next

--Soy prices aren't showing any sign of weakness

CHICAGO (Dow Jones)--U.S. soybean futures rallied for the tenth consecutive trading day Friday, fueled by expectations that smaller South American crops are generating more U.S. export demand.

Soybean futures climbed to five-month highs, as the industry factors in tighter end-of-year inventory forecasts resulting from increased export demand.

CBOT May soybeans ended 10 1/2 cents higher at $13.33 a bushel.

The soybean market has jumped 12% since Jan. 30, with gains driven by drought concerns in South America, particularly southern Brazil. That drove expectations that the U.S. would see more export demand, and more recently there has been a significant pickup in demand.

The U.S. Department of Agriculture reinforced that trend Friday, announcing fresh sales to unknown destinations for both the current marketing year and the upcoming year, which starts in September.

The "day in and day out" announcements of export sales of soybeans solidified trader ideas that government forecasters may be underestimating U.S. soy demand forecasts, said Terry Reilly, analyst with Citigroup in Chicago.

"I'm impressed by the 10-day rally, as soy prices have pushed above strong technical resistance, a reflection that the industry is concerned about demand stripping supplies down to bare minimums this year and next," Reilly said.

Soy prices aren't showing any sign of weakness, as traders remain uncertain about the extent of crop losses in South America. The uncertainties of Brazilian output are drawing traditional buyers of Brazilian supplies at this time of the year back to the U.S.

Private analytical firm Informa Economics on Friday lowered its outlook for the Brazilian soybean harvest. The closely watched agricultural forecaster lowered its estimate for Brazil's soybean crop to 68 million tons from its previous estimate of 70 million, traders said.

Meanwhile, fear that the U.S. Department of Agriculture's estimate of 75 million acres for 2012 U.S. soybean plantings may be too small to meet demand needs is inspiring traders to push futures to levels that make soybeans economically competitive with corn.

Active spread trading where traders buy soybeans and sell corn was featured, as investors worry that a weather problem in 2012 could place a strain on U.S. and world soy inventories, Reilly added.

U.S. wheat futures ended higher, rallying amid short-covering and strength in soybeans. A pickup in export demand, with a surprise sale of U.S. wheat to Iran on Thursday, aided the advances.

Meanwhile, corn futures ended higher, but were unable to generate the same buying as other markets in the absence of fresh supportive news.

CBOT March wheat ended up 11 1/2 cents at $6.70 3/4 a bushel, May KCBT wheat ended 13 cents higher at $7.19, while MGEX March wheat climbed 13 3/4 cents to $8.27 3/4.

CBOT May corn ended up 1 cent at $6.55 per bushel.