Agriculture's market prospects look exciting in theory, but making agribusiness earnings work for the "mum and dad enterprises" which dominate most ag sector industries will require more strategic teamwork with the bank and its different category specialists, according to Mr Wearne.
One of the biggest changes in agribusiness banking in the past decade was the way many clients had recognised the need for good financial planning strategies, including a solid understanding of cashflow trends and new trading ideas.
"They also must have good strategic thinking - what does their business need to achieve and what should it be prepared for," Mr Wearne said.
"That means getting a good financial team around them to work as a true partnership.
"People need to think at a more macro level about markets and other influences - lifting the thinking from immediate management issues on our farms.
"And as bankers we obviously have a big responsibility to help clients be better informed and prepared.
"It's up to us to ask a lot of questions - questions many mum and dad-sized enterprises probably haven't had to look at so much in the past.
"It's more and more important to have these conversations - about commodity prices, exchange rates, interest rates, and more."
Mr Wearne, who took over as executive general manager of regional and agribusiness banking almost three months ago, is relishing the chance to be part of the fast expanding food sector opening up to farmers.
He was keen to promote strategic thinking and the specialist skills available within CBA's agribusiness division to assist farmers and other rural businesses in their decision making.
"We have to be asking businesses in regional areas 'what's your plan?', and 'how are we going to make this work out best for you?'.
"Agribusiness offers opportunities that other sections of the economy are not enjoying, but it's a sector with a lot of clients who are small and mid-sized business people who'll need ongoing education and guidance to adjust.
"They're not just farmers, but also butchers, bakers, trucking businesses, a whole diverse range of pre- and post-farm gate operators."
Part of the bank's relationship building strategy involved reinforcing its agribusiness staffing ranks at a time when some institutions were rationalising because of global financial stresses.
"There's been some very short term cost cutting applied by some banks in the past six months, but we want to make it easier to talk to our clients - we've actually picked up staff from other banks as they shut down services," he said.
Mr Wearne, who replaced Brendan White - one of several CBA executives lured to Bank of Queensland early this year - started with the Commonwealth as a teller in Sydney in 1988.
Between 2004 and 2007 he was head of CBA's institutional banking business in New Zealand.
With 30,000 clients serviced by the CBA's regional and agribusiness banking division and 66 branches Australia-wide, the executive general manager's job is renown for it's testing travel schedule.
Mr Wearne's predecessor averaged 150 nights each year (40pc) away from home, and since taking up the job he has been on the road in every State in the past month, including attending the big AgQuip field days in NSW.
"I wouldn't have taken this on unless I loved what I do," he said.
"But when I'm back in Sydney I have to be brutal with my time at the office - I've got two daughters (aged 10 and 7) and I need to get home to the family."