He succeeds Graeme Smith, currently general manager sales and marketing for Ballance, who will take up a new role as chief executive of animal nutrient manufacturer SealesWinslow from May 1.
Announcing the appointment, Ballance chief executive Larry Bilodeau said Thomson's extensive background in the industry and his leadership within Altum made him a natural candidate for the new and expanded role.
"In previous roles Willie has worked closely with farmers and he also has a strong science background. His leadership in these areas means he is well positioned to lead this part of our business which is increasingly focused on the scientific credibility of products that will help farmers improve their business."
Thomson joined Ballance in 2008 as general manager of summit Quinphos (now re-branded Altum) and in 2009 became responsible for leading the group research and development efforts, environment and strategy.
Born and raised on the family farm in South West Scotland, Thomson held various management positions in the United Kingdom fertiliser industry before relocating to New Zealand in 2003.
