METRO VANCOUVER -- Richmond farmer Bill Zylmans is used to scavengers pilfering his fields for a few berries or nicking the odd pumpkin at Halloween.

But he's baffled as to why anyone would go so far as to dig up and steal thousands of potatoes.

"This is my livelihood," said Zylmans on Thursday.

"Whatever happened to common human decency? Is it someone who is hungry? I just don't think so. (Potatoes) are not an expensive commodity."

Richmond Mounties are investigating after more than 5,000 potatoes were discovered stolen 10 days ago from three of Zylmans' potato fields on Gilbert Street.

Zylmans, a second-generation farmer and owner of W & A Farms, said the total area of the uprooted plants is about the size of a football field.

"I've seen human theft before but nothing like this. I went out at night and through the lights on my tractor I saw this huge circle missing and I thought, 'Good god, this is a real theft,' " he said.

He estimated he's lost more than $5,000 in potential sales.

Zylmans speculated that the thieves might have stolen the crops for commercial profit, but he said they're not the type of potatoes that go on the dinner plate.

The stolen spuds are grown to sell to other commercial farmers for their seeds to restock crops. The seed potatoes are grown using more sprays, said Zylmans.

Sgt. Cam Kowalski, a spokesman for the Richmond RCMP, said Mounties will be stepping up patrols in agricultural areas using the detachment's new all-terrain vehicles.

Zylmans isn't sure what he's going to about the theft but has now been left with the daunting task of installing security measures.

"Do I need more signage. Gates? Locks? Good god, how can put gates around 25 different fields?"

Other farmers in Richmond have also reported more incidents of crop theft, he noted.

"Crop theft is a disturbing offence," said Richmond Mayor Malcolm Brodie, in a statement, adding, " ... the public's support in being good neighbours plays a large role in ensuring farming can remain viable in Richmond."

Brodie said the city is considering installing more warning signs to increase public awareness and deter thefts.

ticrawford@vancouversun.com