Another state senator is leaving the Iowa Legislature to take a position with the Bush Administration in Washington, D.C.Merlin Bartz of Grafton will become the third republican senator to resign in recent months in order to move on to a federal post. He’ll follow JoAnn Johnsen of Adel and Derryl McLaren of Farragut when he takes a post with the Agriculture Under Secretary for Natural Resources and Environment. Bartz will become a special assistant for natural resources and environment.He’ll be dealing with outreach and policy for the Natural Resources Conservation Service and the Forest Service. Bartz, a farmer, is the assistant Senate majority leader, and he says other party leaders understand this is a once-in-a-lifetime opportunity.He says they’re losing some experienced senators, but a republican won the seat given up by McLaren and a special election’s been set for Johnson’s seat, so it’s not a major concern for party leaders. Bartz served two years in the Iowa House, and has been a senator the last ten years. He says the hardest part of the move is giving up farming as they made the decision to rent out their farm so his children can remain in school while he commutes to Washington. Bartz is still working on the exact timing of his resignation. He says he wants it to be soon so his successor can quickly take office. Bartz announced in December he would not seek reelection to the new Iowa Senate District Six post, which includes all of Franklin, Hancock, Winnebago and Worth counties and part of Cerro Gordo County. He’s served in the Iowa Senate since 1992.