Since I do taxes for a living, I feel qualified to comment here.
The deduction referred to here is called the Section 179 deduction. For 2010 it lets you write off the entire value of certain items placed into service in 2010 up to a maximum of $250,000 or the net profit of the business excluding the 179 deduction. In other words, if the farm only made $3.00, you can only write off $3.00. If the farm lost money, you are out of luck for this deduction.
Also, if you sell or dispose of the item before it's depreciation would have normally run its course, you will have to recapture (recognize as income) any "excess" depreciation.
Here's an example. I buy a 2005 F350 in 2010. It cost $25,000.00. I have $30,000.00 in net income. I can deduct all $25,000.00. If I sell the truck (a five-year item) in 2011 for $23,000.00, I will have to show $18,000.00 in income in 2011. That is the $25,000.00 I took in depreciation less the $5000.00 that I would have been allowed had I not chosen to write it all off the first year.
If you are going to keep the item a long time and have the income to shelter, it is a great idea. As with most things in the world of tax, beware. They print the money and they want it back!:ashamed: