Many agri-environmental conservation programs are faced with the problem of imperfect monitoring. This provides farmers with an incentive for noncompliance, because they can receive subsidies without implementing the conservation scheme. In this paper, bidding behavior and auction performance are compared for discriminatory-price and uniform-price auctions in an imperfect monitoring environment. Our theoretical analysis suggests that auction performances are equalized between the discriminatory-price and uniform-price auctions. However, laboratory experiments reveal that, although the discriminatory-price auction has an advantage in terms of reducing policy costs, it is more likely to cause adverse selection. As a result, the uniform-price auction tends to have higher efficiency and cost-effectiveness when compliance behavior is taken into account.