U.S. soybean futures climbed to a nine-week high Thursday on increasing concerns that farmers won't plant as many acres as previously expected.

Soybeans for July delivery, the most actively traded contract, jumped 20 3/4 cents, or 1.5%, to $14.07 a bushel. Corn and wheat futures also advanced at the Chicago Board of Trade.

Leading prices higher were worries that wet weather will limit soybean plantings in the northern Plains and eastern Midwest. Farmers in the regions who have struggled to plant corn, which is seeded earlier in the spring than soybeans, may leave the acres idle to cash in on crop-insurance policies rather than shift the acres to soybeans. Some traders had expected to see a significant shift of acres.

"More economists appear to believe farmers will take prevented planting [insurance] rather than switch corn ground to soybeans, keeping acres under control," according to Farm Futures, an agricultural publication.

Traders are keeping a close eye on plantings due to concerns about low soybean inventories. Prices have pulled back 3.3% since topping a two-year high in February on concerns about strong demand draining supplies.

Farmers need to plant about 78 million acres of soybeans to maintain supplies and usage at current levels, assuming the crop produces normal yields, said Bill Nelson, analyst for Doane Advisory Services in St. Louis. Yet, Linn Group, a brokerage firm, predicted Wednesday that plantings will total just 74.9 million acres, 2.2% below the U.S. Department of Agriculture's latest estimate. Farmers had planted 51% of the soybean crop as of Sunday, below the five-year average of 71% for this time of year, according to U.S. data.

"Planting progress is still slow," said Don Roose, president of U.S. Commodities, a brokerage firm in Iowa.

Price gains accelerated as the rally triggered pre-placed buy orders around last week's high of $13.98 1/4 a bushel, according to traders. That was "the catalyst to get the funds in there to drive the markets higher from a technical standpoint," said Brian Hoops, president of Midwest Market Solutions.

Commodity funds bought an estimated 6,000 soybean contracts, a moderate amount, traders said. They bought an estimated 10,000 corn contracts and 4,000 wheat contracts.

Corn futures felt support from concerns about lower-than-expected plantings, as well. The July contract rose 8 cents, or 1.1%, to $7.66 1/2 a bushel. Soft red winter wheat for July delivery rebounded from a two-week low, jumping 10 1/2 cents, or 1.4%, to $7.69 3/4 a bushel.

Other markets

Soy-product futures finished firmer with soybeans. July soymeal rose 1.5% to $366 per short ton, while July soyoil gained 0.8% to 58.91 cents per pound.

July rice settled up 0.07% at $14.57 per hundredweight as the market stabilized after falling the one-day limit of 50 cents Wednesday. July ethanol gained 0.5% to $2.663 per gallon, and July oats dropped 0.8% to $3.80 a bushel.

At the Kansas City Board of Trade, hard red winter wheat for July delivery soared 2% to $9.09 a bushel. Hard red spring wheat for July delivery strengthened 1.4% to $10.19 1/2 a bushel at MGEX in Minneapolis.