Spatial and temporal trends in soil properties at a soil quality benchmark site in central Nova Scotia

In response to concerns over the widespread soil degradation occurring on Canada's agricultural lands, Agriculture and Agri-Food Canada established a network of benchmark sites to assess soil quality change by monitoring agronomically important soil properties. The Nova Scotia site was established in 1989 on Queens (Gleyed Brunisolic Gray Luvisols) and Debert (Gleyed Dystric Brunisols) soil series under a corn-forage rotation within the Annapolis-Minas Lowlands ecoregion. The objectives of the project were to quantify temporal changes in agronomically important soil properties and determine how the property values vary with the landscape and components of the soil map unit. A 20 x 25 m grid was used in 1990 and again in 1995 to sample soil from the Ap horizon and to locate saturated hydraulic conductivity and penetration resistance measurements. The samples were analyzed for pH, organic C, total N, and available P and K. The results indicate that over 5 yr. organic C, C:N ratio, available P, and saturated hydraulic conductivity declined by 7.9, 4.7, 12.5, and 53%, respectively. Significant differences in pH, organic C, total N, available K, penetration resistance and saturated hydraulic conductivity were associated with selected components of the soil map unit. Slope position had a minimal effect on soil proper ties except for available K where the highest levels were located on middle slope positions. Interactions between particle size and slope position were found. with soils with coarse-loamy sola on upper slope positions having the lowest pH. The results of this study also demonstrated the utility of the method for monitoring soil quality change and the importance of the soil map unit in interpreting the spatial and temporal differences in soil properties.