Donnie MacLeod has been released from prison
Donnie MacLeod served half of the three week sentence imposed for contempt of court.
He continued to state his opposition to trials of genetically modified crops as he was freed from Porterfield Prison in Inverness.
MacLeod, the chairman of the Highlands and Islands Organic Association, was held in contempt of court after being called to give evidence at the trial of another man.
Matthew Herbert, from Oxford, had denied damaging crops at Rhives Farm, near Munlochy, on 7 June last year by trampling an X-shaped design on the field.
When he took to the witness box at Dingwall Sheriff Court, MacLeod said he had been responsible for damaging the field.
However, the 53-year-old organic farmer from Ardersier refused to tell Sheriff James Fraser who else had been involved.
He maintained his silence after being given the weekend to think about his position - and was jailed for 21 days for contempt of court.
The case against Mr Herbert was dropped.
MacLeod was greeted by friends and family when he was released on Thursday.
He told BBC Scotland: "It is just wrong that they should remove the choices that we should have in the form of agriculture in the future in the Highlands, because the GM crop that is there is unwanted, it is uncontrollable, it is unstable and it is totally unnecessary."
The transport and environment committee has given Mr Finnie two weeks to decide whether the controversial experiments are safe in light of new research.
However, Mr Finnie said: "I am operating within the law.
"What I am required to do is take account of that scientific evidence, but I have to do it on the basis of scientific evidence.
"I can't simply do it on the basis of my own personal whim or anyone else's personal whim."