* Weak German data, euro zone crisis re-ignite growth fears
* Crude oil down more than 1 percent
* Copper at one-week low; gold slips from 6-1/2-month top
* Soybeans at lowest levels since mid-August
By Barani Krishnan
NEW YORK, Sept 24 (Reuters) - Commodities fell back Monday, resuming last week's downtrend, after disappointing German economic data and the euro zone's unresolved debt crisis reinforced concerns over slowing global growth.
Copper prices hit a one-week bottom after a September reading on German business sentiment dropped for a fifth successive month to the lowest since 2010. The reading showed that even Europe's No. 1 economy was succumbing to a regional downturn despite stimulus efforts by the European Central Bank.
Crude oil joined the rout, falling more than 1 percent, after a China Beige Book survey detecting a downturn in business optimism added to investor caution on the global economy.
Soybeans fell below the key $16 level the first time in 11 weeks, hurt by a record harvesting pace for the crop in the United States and the dollar's surge to a one-week high against the euro.
The stronger dollar also undermined gold, knocking it off a seven-month high perch reached the previous session.
"There continues to be a concern that there is a global economic slowdown underway," said Bart Melek, head commodity strategist with TD Bank Financial Group.
The bellwether Thomson Reuters-Jefferies CRB commodities index fell 1 percent, touching its lowest since August 20. The CRB had fallen nearly 4 percent last week -- marking its sharpest weekly loss since early June -- after closing down in four of the five sessions.
Up until last week, the CRB had rallied for seven straight weeks from the end of July, as investment funds bought into oil, metals and crop markets, anticipating higher prices from stimulus measures by the ECB and the U.S. Federal Reserve.
Trade data from the Commodity Futures Trading Commision showed that bullish bets on U.S. commodities held by hedge funds and other big speculators rose by $30 billion since the end of July.
In Monday's trade, seventeen of the 19 commodity markets tracked by the CRB settled in the red. Orange juice led the index's losses, falling more than 5 percent, while cocoa , aluminum and silver lost about 2 percent or more.
Copper futures on the London Metal Exchange fell to their lowest levels since Sept. 13 -- retreating from last week's 4-1/2-month peak attained on the back of a $150 billion infrastructure plan in China and the promise of policy easing by the ECB and U.S. Federal Reserve.
LME's three-month copper dropped $98.50 to finish at $8,183 a tonne, after an intraday bottom at $8,150. U.S. copper futures for December shed 5.75 cents, or 1.5 percent, To settle at $3.7315 per lb in New York.
"There is a lot of concern that the actual, physical demand for this stuff is not going to materialize for a while," TD Bank's Melek said, referring to copper.
In oil, London's benchmark Brent crude closed down $1.61, or 1.4 percent, at $109.81 a barrel, after trading below $108. U.S. crude's front-month contract in New York settled off 96 cents, or 1 percent, at $91.93.
Brent dropped 4.5 percent last week, while U.S. crude lost 6.2 percent on increasing concerns about demand for petroleum and indications that Saudi Arabia intends to supply enough oil to lower prices and alleviate any need for the United States and other consumer nations to release oil reserves.
In gold, traders said the precious metal was showing signs of fatigue after five straight weeks of higher prices. Repeated failures to break above key technical resistance above $1,790 an ounce to set a new 2012 high also prompted some investors to lighten their bullish bets.
The spot price of gold, which tracks trades in bullion , was down 0.6 percent at $1,762.20 an ounce by 2:11 p.m. EDT (1811 GMT). On Friday, gold hit a high of $1,787.20, just short of this year's peak of $1,790.30 reached on Feb. 29.
U.S. gold futures for December delivery settled down $13.40 an ounce at $1,764.60.
"There is no question that gold is consolidating its recent gains, but every dip seems to be bought," said Anthony Neglia, president of Tower Trading and COMEX gold options floor trader.
Palladium was another precious metal that sold off, tumbling 4 percent for its biggest one-day decline since March on signs that output was returning to normal in top producer South Africa.
In the case of soybeans, the benchmark November contract at the Chicago Board of Trade dropped to a session low of$15.90-1/4 a bushel in Asian trading and trimmed its decline during the U.S. session, before settling at a 6-week low.
The spot contract is down more than 10 percent in three weeks on profit-taking and the reduction of investor risk after it hit a record high of $17.94-3/4. Prices had soared as the worst U.S. drought in half a century devastated crops in the world's top grains exporter.
U.S. soybean prices remain 12 percent higher from the start of June, when the drought began to fuel a powerful rally.