This program sets up an auction in which the bidders are "farmers" with multiple irrigation permits that can either be used (to earn money farming) or sold to the "state" at auction. The state has set aside funds to buy irrigation permits with the goal of reducing irrigation during a designated "draught" year. The state is interested in obtaining the maximum irrigation reduction for a given expenditure, so the lowest bids to sell permits are accepted. Since permits pertain to various sized plots of land, all bids are submitted on a per-acre basis. As the experimenter, you represent the state. You can specify a target number of acres to be taken out of irrigation, a maximum amount of money to be spent, and a maximum bid. The program determines the permits which will be purchased, subject to the constraints of not acquiring more than the target number of acres, not accepting bids above the maximum, and not spending more than the budget. Bidding takes place in a series of "rounds." In each round, the state announces which permits would have been purchased had that been the final round (given the target acres, maximum bid, and budget constraints). Bidders do not know in advance which will be the final round.
For a description of an actual irrigation reduction auction conducted "in the field" and for details about the laboratory experiments used to test some alternative auction setups, see Cummings, Laury, and Holt (2001) "The Georgia Irrigation Reduction Auction," working paper, Georgia State University.