The demand for legal foreign workers for temporary or seasonal agricultural work now permitted under what is known as the H-2A program will likely increase as the employer sanctions in the Immigration Reform and Control Act of 1986 limit the use of undocumented foreign workers. To protect U.S. farmworkers, the law requires that they be given first opportunity for jobs and that their wages and working conditions are not adversely affected by the use of H-2A workers. The Department of Labor (DOL) relies on two types of surveys to set minimum wages for U.S. farmworkers--a Department of Agriculture (USDA) nationwide survey on farm labor wages and selected DOL-sponsored, state-conducted area surveys of prevailing wages. A General Accounting Office evaluation of the USDA survey indicated that, although the survey is generally sound, it has a potentially serious flaw as used by DOL to set hourly wage minimums. The precision of its wage estimates is unknown and potentially unreliable, and some of the prevailing wage surveys include practices that create potentially erroneous wage estimates. The DOL's practices were also found to provide weak nonwage protections for U.S. farmworkers. Measures for correcting the flaws identified were formulated. (Appendixes include technical data on the USDA survey and comments from the USDA and DOL.) (MN)