(Corrects details on contracts, trading volume in 4th, 5th paragraphs)
* Launch as China embraces commodities derivatives trading
* Caution ahead of critical U.S. plantings report
BEIJING, March 31 (Reuters) - China's investors placed bearish bets on Friday's opening day of soymeal options trading on the Dalian Commodities Exchange, seeking protection as futures tumbled to 4-1/2 month lows ahead of a widely anticipated U.S. government plantings report.
The most-active September soymeal futures closed down 0.32 percent at 2,780 yuan in cautious trading before the U.S. Department of Agriculture releases estimates for U.S. grains plantings for the 2017/18 season - one of the most widely watched reports of the agricultural calendar, and one that can roil prices.
The launch of soymeal options offers a more complicated yet flexible hedging tool for financial investors and soybean crushers alike and spearheads China's efforts to push into commodities derivatives.
To hedge against further volatility, traders positioned themselves on Friday firmly on both sides of the market. They jumped into various contracts: September 3,000 yuan per tonne calls and September 2,600 yuan per tonne puts , the two most-active options on the day.
Turnover on the first day of trading totalled 46,066 calls and puts by market close on Friday, equivalent to 460,660 tonnes of soymeal - well below the more-than-500,000 lots of futures and the more-than-125,000 lots of U.S. soymeal options on the Chicago Mercantile Exchange on Thursday.
But it was in line with expectations for a cautious start.
"I only did several deals to basically try my hands," said Mo Qingping, investment director at ESFund Management Co, with more than 2 billion yuan ($290 million) in assets.
"We didn't spot any good opportunities. "But trading volume for this morning was quite all right given it's a new product," Mo said.
Market watchers said that the complexity of options trading may have curbed some investors' interest for now, contributing to the relatively low trading volume.
But the potential for China's largest agricultural derivatives market remains huge, they said.
"The launch of soymeal options will supplement the futures market and facilitate healthy development of the soy industry," said Chang Qing, chairman of Jinpeng Intl Futures Co Ltd, and professor at futures and financial derivatives research center at China Agricultural University. (Reporting by Hallie Gu and Josephine Mason; Editing by Kenneth Maxwell)