As used in this chapter , unless the context otherwise requires: 1. “Book” , “list” , “record” , or “schedule” kept by a county auditor, assessor, treasurer, recorder, sheriff, or other county officer means the county system as defined in section 445.1 . 2. “Commissioner” means the county weed commissioner or the commissioner’s deputy within each county. 3. “Department” means the department of agriculture and land stewardship. 2000 Acts, ch 1148, §1 ; 2010 Acts, ch 1069, §86 ; 2010 Acts, ch 1193, §49 ; 2018 Acts, ch 1047, §1