This map displays the percentage of organic matter in the surface layer of cultivated soils in the agricultural region of Alberta. Soil organic matter (SOM) is derived primarily from the decomposition of plant biomass. SOM improves both the physical and chemical properties of soil and has beneficial effects on agricultural soil quality. SOM is reported on the map as a percentage using the following classes: less than 2 (very low), 2 to 4 (low), 4 to 6 (medium), 6 to 8 (high) and greater than 8 (very high).This resource was created in 2002 using ArcGIS.