"I will be shorting US bonds," Rogers told a conference in Edinburgh. "I would probably be doing it today if I weren't here," he said.

Bonds in the US have been in a bull market for 30 years, Rogers said.

"In my view that's coming to an end...the bond bulll market is coming to an end. If any of you have bonds I would urge you to go home and sell them. If any of you are bond portfolio managers I would get another job," he said.

Addressing one bond portfolio manager among conference delegates, Rogers said: "If I were you I would think about becoming a farmer. You buy land and learn how to farm."

"In my view it’s going to be a spectacular way to make money," he said, adding: "This is where the great fortunes are going to be made in the future."

Rogers also said he expected to see more currency turmoil in the markets this fall.

"One of the safest investments I see is the renminbi," he said.

“Longer term the US dollar is going to be a total disaster,” Rogers said, urging investors to “think about getting out of US dollars before it’s too late.”

Many investors say the Chinese yuan is a good place to invest, but China's capital controls make it hard for foreigners to buy the currency.

Dollar in Danger

"I would expect to see some serious problems in the foreseeable future….By 2011, 2012, 2013, 2013, I don’t know when, we’re going to have an economic slowdown again," he said. "This time it’s going to be a real disaster because the US cannot quadruple its debt again. Dr Bernanke cannot print staggering amounts of money again."

"How much more can they print without a serious collapse of the US dollar?" he said.

Rogers said he owns the dollar for the moment but he may have to sell it.

"There’s been a huge amount of good news for the dollar and you think it would be strengthening by now…it hasn’t been," he said.

Rogers said the world was facing an ongoing bull market in commodities and said it hadn’t run its course yet. "Commodities are totally underowned," he said.

“This bull market in commodities has a long way to go,” he said, pointing to supply constraints. "If the world economy does not get better I’d rather own commodities than stocks.”

Agriculture is going to be one of the great sectors over the next 30 years, according to Rogers.

Rogers said he had not invested in rare earth commodities. "I missed the whole move in rare earth…I wasn’t paying attention, it’s very clear that somebody is making a lot of money," he said.