Boron deficiency is very widespread in New Zealand but affects mainly brassica root crops such as turnips and swedes. Amongst farm crops, lucerne is also sensitive to boron deficiency but apparently to a lesser degree than swedes and turnips. Pasture responses to boron applications are rare, and are probably confined to clovers. For established lucerne, boron is applied as fertiliser borate at a rate of 10–30 lb/acre mixed with phosphatic fertilisers. With swedes and turnips a similar rate of application of borate is needed for the control of “mottle heart” or “brown heart”, but great care must be taken not to apply borates in contact with seed. Control of the few rare cases of boron deficiency in pasture appears to be obtained by 5 lb of fertiliser borate per acre.