Patterns of soil health for prime agricultural lands in the Greater City of Sudbury Area

Abstract

At the regional scale, soil information regarding commonly employed land uses allows for improved negotiations between land owners, land managers and city planners, and also guides the adoption of sustainable policies and management practices to maintain the finite soil resources required for the on-going preservation of the local agricultural industry under stresses of a changing climate. The increasing management intensity of agricultural soils in the Greater Sudbury region, as elsewhere around the world, is placing negative pressure on the critical soil resource. This pressure is a result of reduced land availability from encroaching non-agricultural land uses, more powerful farming equipment, and a heavy reliance on chemical fertilizers. These diverse pressures are also intensified in the study area due to the strong local demand for topsoil and sod for urban development on the shallow rocky soils of much of the nearby urban area. In this study, a novel geo-referenced database was developed from measured soil health properties sampled in locally significant prime agricultural lands. Using Kruskal-Wallis comparisons, descriptive statistics and coefficients of variation, seven common land uses of the region were evaluated. Soil health properties were found to reflect land use cover and varied along a land use intensity gradient. The results from this study suggest that intensive land management practices in the region decreased topsoil total C concentrations, increased bulk density, narrowed the soil C to N ratio, increased total and available soil major nutrient levels, whilst triggering decreased micronutrient availability. Furthermore, in combination to contrasting soil health differences between dominant land uses, continuous predicted surfaces of soil properties created using GIS software, proved to be useful to highlight spatial patterns of soil properties influenced by local land use decisions. The results in this study confirm that soil resources in the prime agricultural lands of the region are at greater risk of ongoing loss of soil health due to management intensification.