They occurred between Thursday 11 April and Saturday 13 April 2013, from farms near Marton-cum-Grafton and a vehicle hire firm near Great Ouseburn.
The thieves stole a JCB, which was later recovered, a stainless steel water bowser, a blue Norman Raw cultivator and a trailer, which has been converted from a 7.5tonne lorry.
PC Neil Roworth, of Boroughbridge Safer Neighbourhood Team, said:
The bowser is highly distinctive and I am sure that anyone who has seen it will remember it. I urge anyone who has seen the bowser to contact the police or Crimestoppers straight away.
I also need to speak to anyone who may have seen any suspicious activity in the Great Ouseburn or Marton-cum-Grafton areas around the time of the thefts and ask them to get in touch.
Anyone who can assist with this investigation is asked to contact Boroughbridge police on 101, select option 2 and ask for Neil Roworth. Alternatively information can be emailed to email@example.com.
Or call Crimestoppers anonymously on 0800 555 111 quoting reference number 12130057670.