The Bendigo County Court was told Lynton Anthony Melbourne had sex with the 15-year-old girl on a number of occasions.

The offences happened in central Victoria over a three-month period in 2004, when the man was 55.

Last week Melbourne, now aged 56, pleaded guilty to 10 charges of sexual penetration of a child under 16 and six counts of indecent act with a child under 16.

In the Bendigo County Court yesterday, Judge Jane Campton sentenced Melbourne to three years' jail, fixing a non-parole period of 18 months.

The court was told Melbourne had been giving the girl horse riding lessons when a relationship developed between them.

Consensual sexual encounters followed, on one occasion taking place in Melbourne's car.

The court was told Melbourne had been aware of the victim's age at the time and knew what they were doing was wrong.

A victim-impact statement detailed in court stated that the girl now had difficulty forming relationships with boys her own age.

It revealed she felt she had lost her dignity, her school work had suffered and she "hated what Melbourne had done to her".

The court was told that Melbourne had already spent almost a year in detention and that he had been on suicide watch and high doses of antidepressants.

Psychologists' reports discussed in court stated Melbourne did not appear to have psychosexual problems and recognised he had made "a dreadful mistake".

The court was told Melbourne had previously been married and had a son, aged in his 20s.

In sentencing, Judge Campton took into account Melbourne's guilty plea, lack of prior sexual offending and the fact he was unlikely to re-offend.

"(To begin with) the relationship between you and the victim was a positive emotional relationship," she said.

"Unfortunately, it extended into a sexual relationship.

"The victim was still a child in the eyes of the law... and this was a breach of trust."