Soil Erosion Indicator

The Soil Erosion Risk Indicator assesses the risk of soil erosion by water, wind and tillage in the Canadian agricultural landscape. The indicator gives a useful picture of soil health and productivity, particularly when considered with other soil health indicators, such as the Soil Organic Matter Indicator. It is also considered when assessing water quality issues such as the risk of water contamination from phosphorus and pesticides due to the transportation of soil-borne particles to water bodies. This indicator has tracked the state and trend of soil erosion risk associated with Canadian agricultural activities from 1981 to 2011.

Overall state and trend

The risk of soil erosion has been decreasing on agricultural lands in Canada. In 2011, the majority of farmland (74%) in Canada was considered to be at very low risk from soil erosion.

Use the interactive map below to zoom in and explore different regions.  Note that in the Prairies, soil erosion risk is very low primarily due to the use of reduced tillage and no-till, as well as to a reduction in the area under summerfallow (a practice of leaving fields bare). In Eastern Canada and the Maritimes, the risk of soil erosion is also low, although there are isolated pockets of higher risk due to the cultivation of row crops such as sugar beet and potatoes and to a lesser extent corn and soybeans, which provide lower soil cover than cereals or oilseeds.

In addition to exploring the 2011 values, click the play button to view changes over time. Since 1981, there has been a significant decrease in soil erosion risk across the country, which is particularly evident in the Prairies. Most of the decrease in risk occurred between 1991 and 2006. This improvement reflects the reduction in wind and tillage erosion risk (decrease of 11% and 22%, respectively, compared to 1% for water erosion).

Use the interactive map in Figure 2 to explore the change in soil erosion risk between 1981 and 2011. It is apparent that the decrease in risk is most significant in the Canadian Prairies, although all parts of Canada indicate improvements in soil health.

Soil Erosion performance index

The state and trend of the Soil Erosion Indicator can also be seen in the performance index below.

Description - Figure 3

Year	Index Value
1981	65
1986	68
1991	70
1996	74
2001	79
2006	84
2011	84

In 2011, the risk of soil erosion resulting from farming activities in Canada was in the "Desired" category. The index illustrates an improving trend, representing a reduction in erosion risk between 1981 and 2011. This reduction is primarily attributed to the widespread adoption of reduced tillage and no-till, as well as decreases in the use of summerfallow in Manitoba, Saskatchewan and Alberta.

The index tends to aggregate and generalize trends and so should be viewed as a policy tool to give a general overview of state and trend over time.

How performance indices are calculated

Specific trends

Reduced tillage in the Prairies dramatically lowers erosion risk

Prairie soils have seen significant improvements over the past 30 years, resulting from changes in land-use practices such as the reduction in summerfallowing and reduced tillage intensity. The adoption of no-till in cereals in particular, has had the greatest influence in terms of reducing soil erosion risk owing to the large share of cropland devoted to cereals on the Prairies. The 3-panel map below shows the change in erosion risk from tillage only for the three Prairie Provinces of Alberta, Saskatchewan and Manitoba, and for the Census years 1981, 1991 and 2011. You can also zoom out to explore the improvements in other parts of Canada for the same time periods.

Reason for this trend

The primary reason for the improvement in this indicator in Canada is due to the shift away from intensive tillage in the Prairie region. Intensive tillage removes most of the crop residue from the soil and leaves the subsoil exposed, which is then vulnerable to erosion from the effects of wind and water. Figure 5 shows the change in percentage of farmland between 1981 and 2011 under no-till as well as under summerfallow for the Prairies (Alberta, Saskatchewan and Manitoba) as well as for Canada as a whole. Because the Prairie region accounts for over 85% of farmland in Canada, changes in these provinces significantly impact the national averages.

Description - Figure 5

Percentage of farmland under no-till

	1981	1986	1991	1996	2001	2006	2011
Manitoba			5	9	13	21	24
Saskatchewan			10	22	39	60	70
Alberta			3	10	28	48	65
Canada			7	16	30	46	56

Percentage of farmland under summerfallow

	1981	1986	1991	1996	2001	2006	2011
Manitoba	8	7	4	4	3	2	1
Saskatchewan	26	20	20	16	11	8	5
Alberta	12	10	8	7	6	4	2
Canada	14	12	11	9	6	4	3

Why this indicator matters

Soil is an essential resource for agriculture. Erosion of topsoil can result in lower fertility, which affects productivity, and ultimately profitability for the producer.  The loss of soil from farm fields can also cause water quality issues. Nutrients, pesticides and pathogens can attach to soil particles and move into water bodies with the eroded soil. Sedimentation—the build-up of fine sediment in water bodies—can also affect aquatic species.

The protection of agricultural soils through the implementation of beneficial management practices can ensure the long-term health of this important resource.

Beneficial Management Practices

The same practices that increase soil organic matter and soil cover will lower soil erosion risk. In the Prairies especially, producers can reduce the risk of soil erosion by reducing summerfallow and tillage intensity and by converting annual crops to perennial cropping systems. In areas vulnerable to wind erosion, such as the Prairies, shelterbelts and cover crops can be considered. In regions where crops are grown on slopes, particularly in the case of field crops such as potatoes, consideration should be given to systems such as strip cropping, with plantings running across the slope rather than up and down the slope. Erosion control practices such as terraces and grassed waterways that slow the velocity of runoff can also help reduce soil loss.

How performance indices are calculated

The agri-environmental performance index shows environmental performance state and trends over time, based on weighting the percentage of agricultural land in each indicator class, such that the index ranges from 0 (all land in the most undesirable category) to 100 (all land in the most desirable category). The equation is simply “(% in poor class multiplied by .25) plus (% in moderate class multiplied by .5) plus (% in good class multiplied by .75) plus (% in desired class).” As the percentage of land in the “at risk” class is multiplied by zero, it is not included in the algorithm.

The table below shows the index classes. The index uses the same five-colour scheme as the indicator maps whereby dark green represents a desirable or healthy state and red represents least desirable or least healthy.

The index tends to aggregate and generalize trends and so should be viewed as a policy tool to give a general overview of state and trend over time.

Related indicators

• The Soil Organic Matter Indicator tracks the health of Canadian agricultural soils as it relates to soil carbon content.
• The Soil Salinization Indicator examines salinization risk to Prairie soils.
• The Soil Cover Indicator assesses the number of days in a given that soils are protected by crops or snow.

Additional resources and downloads

• For detailed information on this indicator, please see the publication entitled Environmental Sustainability of Canadian Agriculture, Agri-Environmental Indicator Report Series - Report #4.
• Discover and download geospatial data related to this and other indicators.