GRAINS-Chicago soybeans rise as investors weigh impact of US-Iran war

BEIJING, March 23 (Reuters) - Chicago soybean futures climbed on Monday as investors weighed U.S. and Iranian threats to target energy facilities that could escalate the war and add further pressure to the global commodities market.

Wheat and corn futures edged higher.

The most-active soybean contract on the Chicago Board of Trade (CBOT) Sv1 was up 0.34% at $11.65-1/2 a bushel, as of 0340 GMT. CBOT wheat Wv1 gained 1.1% to $6.02, and corn Cv1 climbed 0.8% to $4.69 a bushel.

Iran warned it would strike energy and water infrastructure across the Gulf if U.S. President Donald Trump follows through on his threat to attack its electricity grid.

U.S. President Donald Trump on Saturday threatened to "obliterate" Iran's power plants if Tehran did not fully reopen the Strait of Hormuz within 48 hours, a significant escalation barely a day after he talked about "winding down" the war, now in its fourth week.

The prospect of tit-for-tat strikes on civilian infrastructure further unsettled oil markets, with prices opening choppy in early Asia trading. O/R

Grains and oilseed prices have broadly tracked fluctuations in crude oil during the U.S.-Israeli war on Iran, reflecting the widespread use of corn and soyoil in biofuels and investor interest in the crops as an inflation hedge.

"Wheat futures also firmed on the back of concerns regarding drought conditions in the US Plains," said Claire Adams, agricultural Analyst at Bendigo Bank Agribusiness.

Weather forecaster Vaisala said last week that ongoing dry weather in the central and southern Plains would maintain low moisture for winter wheat over the next 30 to 60 days.

In South America, Argentina is shipping out grains at a strong pace this season as record sunflower exports and booming corn sales help absorb one of the country's biggest harvests in years, the Rosario grains exchange said on Friday.

In Brazil, the world's largest soybean producer, China has eased rules related to the presence of weeds in Brazilian soybean cargoes, local media reported on Friday, citing a document from the local government.

China is not going to implement a zero-tolerance policy for weed contamination in shipments, according to the report.

Farmers in Brazil harvested 65.79% of the expected 2025/26 soybean area, below the 73.84% seen at this time last year, but near the five-year average of 66.96%, consultancy firm Patria AgroNegocios said on Friday.