Provenance & quality
Annual census of agricultural and horticultural activities for England, Scotland and Wales is conducted on commercial holdings, defined as holdings of more than 5 ha agricultural land, 1 ha orchards, 0.5 ha vegetables or 0.1 ha of protected crops and ornamentals, or more than 10 cows, 50 pigs, 20 sheep, 20 goats or 1000 poultry. Note that these thresholds have only been in place since 2010. Each farmer declares the agricultural activity on the land via a postal questionnaire. Since the late 1990s the agricultural census in England and Wales has been conducted as a sample survey in which data is only sought from a proportion of holdings in each year, as low as 30% of commercial holdings in some years (approx. 30,000 holdings). Since 2007, cattle numbers have been taken from the Cattle Tracing Scheme. Data for non-surveyed farms are interpolated from the most recent data for those farms using the trends on comparable farms.