Blustering Barnyard is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Storm (Pretend it works on a land.) : Add one mana of any color and lose life equal to the number of barnyards you control. Channelstorm — , Discard this card: Choose worth of modes equal to the number of spells that have been cast this turn. — Create a 1/1 white Bird token with flying. — Create a 2/2 white Horse token with horsemanship. — Create a 3/3 green Ox token with trample.