A Harvard economics professor has been accused of neglecting the standard market practice of paying for goods and services by trying to steal a truckload of manure from a nearby farmer.

Phillip Casey says Martin Weitzman, a Harvard University professor of economics, has been stealing manure from the farm for years.

Casey found Weitzman on the property, blocked in Weitzman's pickup truck, and called police. At that point, the professor began to bargain a price for the manure. Casey told police he did not enter into that conversation because he had warned Weitzman before and wanted the thefts to stop.

"He offered me $20 for it and then $40 for it,'' Casey said.

The farm sells the manure for $35 a truckload and also uses it to fertilize a pasture.

Weitzman was charged with larceny under $250, trespassing, and malicious destruction of property for tearing up some land with his tires.