(CNN) The US Department of Agriculture is shrinking payments offered to employees who applied for buyouts rather than relocate to the greater Kansas City area, according to a document obtained by CNN.

The one-time payouts are being reduced from $25,000 to $10,000 because so many workers applied, according to the document.

The American Federation of Government Employees, which represents workers at the affected agencies, says employees of the two research-related agencies that are being moved out of the the Washington area are "extremely upset."

A USDA spokesperson told CNN that the department said the change was made in order to offer payments to all eligible employees, rather than offer only the higher amount on a first-come, first-served basis. Workers still have the option to refuse the reduced payment if they decide to relocate, the spokesperson added.

The change comes after a union-compiled survey released last month showed an overwhelming number of the reassigned employees will likely choose to leave rather than relocate -- losses that could drain institutional knowledge and talent at two units that fund agricultural research across the nation and produce crucial reports, including data on agricultural markets and estimates of US and international agricultural productivity.

Read More