Sell the Porsche, buy a tractor and reap returns. Farmland prices that more than doubled in England in the past decade may repeat the gains, according to property adviser Knight Frank LLP.

The average price of the land surged 164 percent to a record in the last 10 years, second only to gold among “major asset classes,” on demand for food commodities, it said.

The chart shows farmland prices, in purple, have outperformed an index of prime residential homes in central London, in orange, and English country houses, in red, according to figures compiled by Knight Frank. The S&P GSCI index of agricultural commodity prices, in green, shows they climbed last year, accelerating in the final quarter.

“It seems fitting that farmland, which has been one of the strongest performing assets in recent years, should end the decade at an all-time high,” Andrew Shirley, head of rural land research at Knight Frank, said in an e-mailed statement. “The ongoing imbalance between supply and demand means prices will continue to increase and may well double before the end of the next decade.”

Gains in agricultural properties are partly fuelled by a lack of land, because it’s being given over to development, demand from commercial producers and “lifestyle” purchases of residential farms, the company said in the statement.

Graham Birch, 49, is one investor who made the move, quitting last month as manager of BlackRock Inc.’s BGF World Gold Fund to run a dairy farm in southwest England. He first bought land for his farm in October 2007. Knight Frank’s index shows farmland prices rose 28 percent since then.