The changes will increase the lower threshold attracting 100% relief from £6,000 to £12,000, and extend the upper threshold to £15,000,
Agricultural property is exempt from business rate liability but diversifications including farm shops and equestrian facilities are not. Small Business Rate Relief may apply there in certain circumstances.
Currently, property with a rateable value of up to £6,000 has 100% relief, with a sliding scale for properties in the £6001-£12,000 range. Those reliefs will continue until 31 March 2017, as confirmed in the 2015 Autumn Statement. After that, the new rates of relief will apply.
NFU members can read a briefing on the changes here (you will be asked to log-in)