The most-active soybean contract on the Chicago Board Of Trade was up slightly at $9.07-1/4 a bushel by 0357 GMT, after gaining over 1 percent in the previous session.
Farmers expect soybean yields and output in Mato Grosso, Brazil's largest producing state, to be hit by scarce rains in December. Dry weather and high temperatures are also accelerating the soybean cycle, leading some growers to anticipate harvesting even at the risk of lowering yields.
Wheat futures rose 0.2 percent at $5.07-3/4 a bushel in line for a second session of gains on short-covering and concerns about excessive rains in Argentina.
Russian wheat exports rose sharply to 1.2 million tonnes in the last week of December, but trade is expected to be thin during the Dec. 30-Jan. 8 New Year holiday, said an agricultural consultancy.
Meanwhile, corn slipped 0.1 percent to $3.75-1/2 a bushel after edging up 0.2 percent yesterday. Traders are also optimistic about easing trade tensions between China and the United States, and the prospect that China could buy more U.S. soybeans as a trade delegation heads to Beijing for talks on Jan. 7.
The U.S. Department of Agriculture will decide on Friday whether to delay a slew of key crop reports scheduled for release on Jan. 11.
A partial government shutdown has prompted the USDA to suspend daily and weekly export sales reports, worrying grain traders who rely on the data.