GRAINS-Chicago soybeans at 3-week high on biofuel talks, Brazil harvest, US tariffs weigh

BEIJING, March 31 (Reuters) - Chicago soybean futures hit a record high since March 10, driven by domestic demand prospects from biofuels policy talks, but Brazil's bumper harvest and U.S. tariff concerns limited gains.

The most-active soybean contract Wv1 on the Chicago Board of Trade (CBOT) gained 0.15% to $10.24 a bushel, the highest since March 10 and marking a third straight session of gains as of 0207 GMT.

U.S. President Donald Trump's administration has asked oil and biofuels producers to hash out a deal on the next phase of the nation's biofuels policy, Reuters reported last week.

In top soybean exporter Brazil, soybean crop for 2024-2025 is forecast at a record 172.1 million tons, agribusiness consultancy Agroconsult said last week, with strong export demand from China.

Traders are focused on the U.S. Department of Agriculture's (USDA) reports and April 2 tariffs. On Sunday, Trump said the upcoming reciprocal tariffs would include all nations, not just a select group with the largest trade imbalances.

Corn Cv1 slipped 0.44% to $4.51 a bushel on expectations of massive planting and tariff concerns, which may provoke retaliation from key agricultural partners.

U.S. corn planting is expected to rise to 94.361 million acres in 2025 from year-ago 90.594 million, according to analysts polled by Reuters.

Wheat Wv1 fell 0.19% to $5.27 a bushel, pressured by favourable weather in the U.S. and Russian wheat belts and expectations of smoother exports from Russia and Ukraine due to the U.S.-backed ceasefire deal.

Commodity funds were net buyers of CBOT corn, soybean and soyoil futures contracts on Friday, traders said. They were net sellers of wheat and soymeal futures contracts, traders said. COMFUND/CBT