* Base metals, oil, gold and platinum extending gains
* Eyes on Fed for extra stimulus from policy meeting
* Grains await key USDA report on U.S. drought
By Veronica Brown
LONDON, Sept 12 (Reuters) - Rallying metals and oil markets picked up steam on Wednesday, with crude up for a fifth day and gold hitting six-month highs, boosted by a German court's approval of a euro zone bailout fund and hopes of more monetary easing from the Federal Reserve.
Platinum also hit its highest point since early April amid concern about spreading labour unrest in South Africa, the metal's top producer.
German backing to the euro zone's new 700 billion euro European Stability Mechanism boosted the bloc's ability to face up to its debt crisis. The court's approval was a central requirement for the European Central Bank's plan to buy the bonds of struggling euro members.
With that decision taken, markets are positively positioned for the Fed's two-day policy meeting. The expected announcement of extra stimulus for a flagging U.S. economy was seen sparking beneficial ripples through commodity markets.
"Once again the big question is QE (quantitative easing) or not," said Gabriel Garcin, a portfolio manager at Europanel Research & Alternative Asset Management in Paris, which invests in European hedge funds and CTAs.
"If they do, it could really push up prices. Then once again the drivers of commodity prices would shift from supply demand fundamentals to more risk-on, buy everything that are risky assets."
Brent crude for October delivery, which expires on Thursday, was up 72 cents at $116.12 a barrel, on track for its highest close since Aug 16.
Gold shot to $1,746.20 - its strongest in six months. The metal has risen twice as many days as it has fallen in the last calendar month, while copper and aluminium were up for their fourth and ninth days respectively.
Other so-called risk markets got a shot in the arm from the German court bailout decision, with global shares rising , but Spanish and Italian bonds near the centre of the financial storm were little changed.
In precious metals, spot platinum and the metal's price in South African rand hit multi-month highs, with investors prompted by spreading unrest in the country that controls around 80 percent of global output.
South African police said striking miners had blockaded roads leading to shafts belonging to number one producer Anglo American Platinum.
The price has risen by nearly 20 percent since a strike at number three producer Lonmin turned violent last month, leaving 44 dead and dozens injured in clashes between police and workers.
Yet a forecast surplus of metal stemming from faltering demand from the European car industry could limit further price gains, analysts said.
"The situation is delicate, very politically sensitive. But we have to sit back and take a more neutral look at the market and say this is all sentiment driven. It's debatable as to how much of a sustained rise this will be once the dust has settled," Societe Generale analyst Robin Bhar said.
Chicago soybeans rose from a three-week low, while corn gained after two days of losses in positioning ahead of key U.S. reports which will shed more light on damage caused by a historic Midwest drought.
Funds have been liquidating bullish bets in the markets heading into U.S. Department of Agriculture supply-demand and crop production reports due at 1230 GMT on Wednesday.
"We are expecting a downgrade in soybean production which is mainly based on the area assessment," said Luke Mathews, a commodities strategist at the Commonwealth Bank of Australia.
"It will be the same scenario for corn, abandonment (of acres) is likely to be revised higher for corn, resulting in overall downgrade in production."
Looking at ways to tackle repeated food price spikes stemming from volatile cereal markets in recent years, French president Francois Hollande launched a global campaign to win support for creating strategic stockpiles of agricultural commodities.