Nearly everyone has one

Nierenberg says the potential for the technology goes far beyond Asia. She's been traveling across sub-Saharan Africa for the last eight months, and everywhere she goes, from remote villages in Uganda to poor farmers in Niger, nearly everyone has a mobile phone.

"Because it's easy and cheap and every farmer can basically get their own [mobile] phone or borrow someone's down the road, I think it's increasingly a way for them to gain access to things they didn't have before," she says.

In Zambia, for example, farmers without bank accounts can use their cell phones to buy seeds and fertilizers. They can also find out how much their crop is selling for in the city markets.

"They can decide whether they want to travel all the way from their village to the city," she adds, "because sometimes farmers get there and prices are too low." Their mobile phones could save them a trip.

So, while it may not be good for plowing a field or harvesting vegetables, the mobile phone is becoming one of a farmer's most valuable tools.