An Ecosystems Approach to Quantify Soil Performance for Multiple Outcomes: The Future of Land Evaluation?

Abstract

Among natural resources, soils are often forgotten and poorly represented in ecosystem service frameworks and decision making processes, even though they are a non-renewable resource and the foundation of terrestrial ecosystems’ function and health. This study used a novel methodology to (i) quantify the ecosystem services provided by dairy-based agro-ecosystems on two contrasting soils in New Zealand using a process-based model, (ii) determine the economic value of each service using on-farm built capital substitutes, and (iii) explore the merits of incorporating an ecosystems approach into land evaluation and resource management. Ecosystem services quantification proved insightful in distinguishing and quantifying the inherent differences in the capabilities of two contrasting soils to contribute to service provision by translating them into differences in performance under the same use, before calculating economic values. The economic value of the services provided by the system with Horotiu was on average 35% greater than the economic value of the services provided by the same land use on the Te Kowhai soil, with differences in the provision of some services (provision of food, flood mitigation, and the filtering of nutrients and contaminants) more pronounced between the two soils than others (provision of support, recycling of wastes). Regulating services had greater economic values than provisioning services for both agro-ecosystems. Existing limitations of land evaluation processes can be addressed by an ecosystems approach through increased emphasis on inclusive, quantitative assessments that reflect society’s desired outcomes as informed by stakeholder input.