ACRI - Agroclimatic Resource Index

The Agroclimatic Resource Index (ACRI) provides an approximate method for quantitatively comparing quality of the agroclimate for agriculture in different parts of Canada (Williams, 1975). It is calculated by considering growing season length, temperature and moisture as they relate to forage yields.

The index is based on long-term records of hay yields, since it is only the hay crop which is grown across Canada and can potentially use the full growing season. Index values range from 3.00 for Kent-Essex counties in south-western Ontario to a low of 1.00 for the Northwest Territories. The index is based on a growing season which is defined as the period in days between the last killing spring frost (-2.2 °C) and the first killing fall frost, with downward adjustments for Maritime climates for inadequate summer heat, and in the Prairie region for aridity.

The ACRI values for each map unit were coded by manually superimposing a map of ACRI isolines onto the Soils of Canada map, and selecting the lowest and highest values of the isolines surrounding each map unit (Dumanski and Stewart, 1981).


ACRI - 4 Items
Code Definition
MAPUNIT Soil Map Unit (Relate Field)
ACRIHI Agroclimatic Resource Index, high value
ACRILO Agroclimatic Resource Index, low value
CAMUI Climatically available Moisture Use Index