He was found about 100m from the pump with two 20-litre containers full of diesel in the back of his ute but told police he took the fuel from his father's farm. Smith said he was waiting for a "mate" and had gone into the yard to use the hose for a drink of water.
Police prosecutor Sergeant Garry Wilson said Smith was a former employee who was "angry" at the farmer who had previously fired him.
During sentencing Judge Morris told Smith he had a long list of convictions and could face jail if he reappeared in court.
"You will need to be careful ... there is nothing much between an electronically monitored sentence and imprisonment."
Wairarapa Federated Farmers president Jamie Falloon said farmers throughout the district had had enough and were taking precautions to protect their property. Some had installed up-to-date security measures like CCTV cameras and sensor alarms.
But what concerns him most are the "risks" farmers and thieves are taking.
The thieves are stealing everything from valuable quad bikes to much needed petrol for farm vehicles.
Farmers were fighting back, Mr Falloon said.
"They are a lot more alert to what is out there to help them."
He spoke about the Pirinoa farmer who had fallen asleep on the couch watching rugby and awoke to hear someone driving off on his quad bike.
The farmer jumped in his ute and followed the thief, putting himself and the thief in danger.
In these situations, there was the danger of a quad bike being crashed into by the pursuing farmer who could himself end up in court on serious charges, he said.
He understood thefts affected the farmer's ability to run a business and why they are taking on the culprits.
"They need to be careful ... it's like poaching, in the end someone is going to get seriously hurt. [Farmers and thieves] are taking a real risk with their lives.
"There is a real danger when people are fleeing in the dark. There is potential for something to go wrong," he said.
Mr Falloon urged farmers to call police and report all crimes.
Masterton police Senior Sergeant Jymahl Glassey said it was a danger to confront the criminals, especially on isolated rural properties.
Farmers should dial 111 as thieves could be armed, he said.
"You don't know what they have brought with them to protect themselves."
Mr Glassey doesn't advocate farmers should chase thieves but if "human nature" did kick in they needed to remain a good distance behind and relay information to police using a mobile phone.