Tony Aitken has been confirmed as the co-operative’s new chief executive for an 18-month term, two weeks after being appointed in an interim capacity.

Ruralco chairman Sir David Carter said former chief executive Rob Sharkie’s resignation was "a surprise to many staff and stakeholders" and the board decided an 18-month of appointment would provide a period of certainty and stability.

"It then gives the board time do initiate a recruitment process if and when it is required," he said.

Aitken, the former general manager of people and culture, told the Guardian he was humbled to be appointed to the role.

"Ruralco has a rich history of supporting farmers and I’m excited to continue this legacy to support a sustainable future for our farming communities.

"I feel proud to have been given the opportunity and look forward to leading a great team on the journey ahead."

Aitken said he enjoyed helping organisations grow and his strengths-based approach was the right fit for Ruralco.

"I believe that people naturally want to do well, and a culture that enables that will ensure continued business success for the co-operative."

Aitken acknowledged that the agriculture industry was facing many challenges.

"Our plan is to continue to have farmers backs and support them through these challenges as Ruralco has done for the past 60 years," he said.

Carter said Ruralco's board believed Aitken's skill set was a good fit for the co-operative, and his appointment provided continued stability for the business.

The chairman said Ruralco's financial position was strong, but expected the trading environment to be tougher than last year.

"We will continue to review, respond and adjust our business model as the year progresses.

"My own farming business is doing what any prudent would do - consider all costs and consolidate whenever necessary. Ruralco is doing the same," he said.

• Sharon Davis