Agricultural Land Classification Grade and Job number for post-1988 ALC surveys for England Only. Polygons showing 5 classes of agricultural land plus classifications for urban and non-agricultural land. Grade one is best quality and grade five is poorest quality. A number of consistent criteria were used for assessment which include climate (temperature, rainfall, aspect, exposure, frost risk), site (gradient, micro-relief, flood risk) and soil (depth, structure, texture, chemicals, stoniness). Full metadata can be viewed on data.gov.uk.