The family-owned business, which already has three outlets in Barnstaple and Holsworthy in Devon and at Callington in east Cornwall, will replace Cornwall Farm Machinery, who have decided to relinquish the John Deere franchise from that date.
Smallridge Bros plans to open a new outlet to serve customers in the region, and details of this will be confirmed in due course.
Smallridge Brothers was established at East Collabear near Barnstaple in Devon in 1977, when brothers David and Michael Smallridge started an agricultural engineering partnership, and John Deere signed the business as an official franchise dealership in 1990.
In 2011 the company moved into Cornwall for the first time with a second outlet at Callington, and in 2014 a third outlet was acquired at Holsworthy in Devon when the dealership took over the John Deere business previously managed by Robert Cole Agricultural Engineers Ltd.
Smallridge Bros, which also operates a number of other franchises including Kramer telehandlers and loaders, currently employs over 70 staff.