In the weeks prior to his death, Colby had qualified for his first Waikato/Bay of Plenty Regional Final of the FMG Young Farmer of the Year.
The contest was held in Rotorua earlier this month.
"It was a tough day for me, having to compete without Colby there," said Zara, who was also a finalist.
"As I was completing the modules, I imagined him laughing at all my little stuff-ups and safety violations."
Colby's spot on the day was left vacant as a mark of respect and finalists' hats were embroidered with his name.
Zara also had the words "in memory of Colby Harris, much loved friend" embroidered on her sleeve.
"Colby's mum was messaging me throughout the day and his dad was there and told me he was proud of my performance," said Zara.
"That support meant a lot."
Zara is urging people in rural Waikato to get off the farm and attend a special comedy night on Saturday, April 21.
Internationally acclaimed comedians Andre King, Nick Rado, Paul Ego and Tarun Mohanbhai will perform at the Sir Don Rowlands Centre in Karapiro.
"Tickets are just $10 each, with all proceeds going directly to Farmstrong," said NZ Young Farmers chief executive Terry Copeland.
"It should be a great night with lots of laughter."
"NZ Young Farmers is proud to help organise this important, much-needed event," said Terry.
"We want to be a leader in supporting and nurturing the health and wellness of young New Zealanders."
General admission tickets are available by visiting www.youngfarmers.co.nz/nzyf
