Official cover and souvenir programme of the 2nd day of the New Zealand Silver Plough Final: Grassland at Lincoln, 15th May 1980, one of the events at the 27th World Ploughing Contest. The cover pictured here uses a 99c postal stationery envelope that was overprinted especially for the event, with a 30c stamp, both jointly date stamped 15th May 1980, with registration label no. 072.