The FarmVille Tractor allows you to plow four squares at once. You also don’t have to wait for your person walk to the squares in order to do it, like you do when you plow normally. You earn the same number of experience points (one per square) and it costs the same (15 coins per square). The only difference is you earn four experience points at a time and it deducts sixty coins at a time.

One major drawback is that the tractor uses gas. When you buy the tractor, it comes with plenty of fuel. I believe it takes one fuel to plow each square, but I’m not entirely sure. When you run out, you can either buy more gas from the market, but that costs Farmville dollars, which you have to buy with real world money. The other option is to just wait. Every two and a half minutes the game will give you a small amount of more fuel.

At a cost of 30,000 coins, the FarmVille Tractor will allow you to plow a 2×2 section at a time as opposed to a
single plot at a time without the Tractor.
As with most items in the game, buying them rewards you with XP.
The FarmVille Tractor does not help you harvest or plant your crops. All it does is help you plow the fields.
It appears to give 300XP when purchased.