Follow-up...

I spoke to the Randolph Township tax assessor's office today(1). They admit that this property (see below for details) is NOT farmland assessed. They could not explain why this property -almost 70 acres is taxed for only a couple of hundred dollars per year. The office said they think "there might be crop land" on the property. I informed them that nothing is being grown or harvested -neither animals or crops of any kind on this property. Either way, the property does NOT have a farmland exemption anyway. Perhaps at some point years ago there might have been, I can't rule that out, as it was sold by unknown entity called "Calais Road Farms LLC" to Sal Campo's (biggest developer in Randolph) development company "Heritage Farms LLC".
I am left with only one explanation: Occam's Razor: "All other things being equal, the simplest solution is the best".
In this case the likeliest explanation is summed up in one word: connections
A gift from the town council to the town's biggest developer and largest campaign contributor to the same town council. See below for more details on this gift.
Ah, the circularity of small town politics and business.

(1) Tax Assessor Barbara Gothie, 973-989-7074 http://www.randolphnj.org/townhall/township_directory/