GRAINS-Corn slumps as ethanol makers feel coronavirus constraints

* Corn down as oil rout pressures ethanol, soybeans follow

* Eye on South American shipments amid coronavirus curbs

* Market awaits USDA plantings, quarterly stocks data (Adds closing prices, soybean gains, analyst comments)

By Karl Plume

CHICAGO, March 30 (Reuters) - U.S. corn futures fell more than 1% on Monday on slowing grain demand from ethanol makers, as tightening coronavirus pandemic travel restrictions limited demand for the biofuel.

Soybeans ended mixed, with nearby contracts lifted by firm soymeal prices and concerns coronavirus restrictions may impede South American soy shipments. Wheat ended mostly higher as top exporter Russia appeared poised to restrict shipments.

A further drop in crude oil prices kept pressure on grains markets as ethanol producers, users of around a third of the U.S. corn crop, have slashed production or shuttered plants.

"We continue to see pressure on the basis. We continue to see concern about ethanol plants," Ted Seifried, chief market strategist for Zaner Ag Hedge, said.

"There was hope that today we'd start to hear some better news about maybe coming out of isolation relatively soon, but instead we're hearing it will take more time. It's weighing on the energy market and you can't exclude corn from that," he said.

U.S. President Donald Trump on Sunday extended his stay-at-home guidelines until the end of April, dropping a plan to get the economy up and running by mid-April.

Chicago Board of Trade (CBOT) May corn fell 4-3/4 cents to $3.41-1/4 a bushel, while CBOT May wheat dropped 1-3/4 cents to $5.69-1/2 a bushel.

May soybeans ended up 3/4 cents at $8.82-1/4 a bushel, lifted by strong soymeal demand prospects amid tighter supplies of distillers grains, an ethanol byproduct and feed ingredient.

"With beans, it's all been about the meal," said Jeff French, analyst with Top Third Marketing. "They need protein, and the cheapest market is meal."

Soybean futures also remain underpinned by the risk of logistical snags in South America and reduced palm oil production in Malaysia due to coronavirus.

Argentine shipments of soy, corn and other agricultural exports were delayed as the government ramps up inspections of incoming ships.

Grain investors squared positions ahead of two key U.S. Department of Agriculture (USDA) reports due Tuesday on prospective U.S. plantings and quarterly grain stocks.

Analysts polled by Reuters expect the report to show U.S. corn and soybean plantings above last year's weather-reduced acreage and tighter year-on-year stocks of grain as of March 1.

Weekly USDA export data showed a larger-than-expected volume of corn was inspected for export last week, while soybean and wheat inspections were near the low end of trade estimates. (Additional reporting by Christopher Walljasper in Chicago, Gus Trompiz in Paris and Naveen Thukral in Singapore, Editing by Alexander Smith and Tom Brown)