Canadian agri-environmental indicators related to land quality: integrating census and biophysical data to estimate soil cover, wind erosion and soil salinity

A Canadian initiative to define and estimate indicators of the relationship between agricultural activities and environmental quality has been under way since 1993. This paper focuses on those indicators related to land quality and highlights the use of GIS to reconfigure land use and climatic data to a soil landscape spatial model in order to apply models of soil degradation. The 1981 and 1991 Census of agriculture data from a cadastral base and climatic indices from iso-contour maps are related to the soil landscapes of Canada to identify trends in the amount of soil cover, the risk of soil erosion by wind and the risk of soil salinization. Results indicate that soil cover has improved by about 11% through the use of conservation tillage and crop residue management and reduced summerfallowing, and that the risk of wind erosion in the prairies has decreased by 7% in the 10 years. The risk of soil salinization has remained constant on 93% of cropland, decreased on 7% and increased on <1%. It appears that the improvements in soil quality protection have occurred despite some shifts to more intensive cropping systems. Crown Copyright (C) 2000 Published by Elsevier Science B.V. All rights reserved.