Lorna E. Jarrett

Soil Security: A Rationale

The concept of soil security has strategic value in that it can serve to focus and guide the development of policies addressing the six global existential challenges, such that interventions for one challenge result in favourable effects on other challenges. Soil security arises from both top-down (global challenge) and bottom-up (societal value) considerations. We envision it as a homologous concept to those of food and water security. The major goal is to measure and manage the five dimensions of capability, condition, capital, connectivity and codification.

General Concepts of Valuing and Caring for Soil

Beginning in the mid-twentieth century, concepts have arisen to define how society values and cares for soil. The earliest, soil conservation, focused narrowly on the causes and prevention of soil erosion. Other early concepts were land evaluation and capability and soil care. More recently, a large number of concepts have been proposed. These have a broader scope, reflecting increases in scientific understanding of soil and its interactions with other parts of the biosphere and with human society. They include soil function, soil quality, soil health, soil condition, soil change, soil resilience, soil ecosystem services and soil protection. However, none of these concepts includes the full range of ways in which society needs to value and care for soil, and some are vague in definition. The concept of soil security has five dimensions: capability, condition, capital, connectivity and codification (McBratney AB, Field DJ, Koch A et al., Geoderma 213:203–213, 2014). These recognise specific concepts of soil value and care.

The Value of Soil’s Contributions to Ecosystem Services

As a contribution to the 2015 Global Soil Security Conference, we estimated the value of ecosystem service contributions by soil. The general purpose of this estimate was to give soil a value with respect to natural capital, to compare that value to other values recognised in the global economy and to start a conversation among soil scientists and economist about the value of soil. In particular, we want to incite a conversation about the value of soil beyond that discussed using commodity prices. The simple estimate of the value ecosystem services from soil is approximately 11.4 trillion USD, which compares to the 2015 gross domestic product of the USA at 15 trillion USD. The original source used for this estimate has been updated. In general the updated values of global ecosystem service are now at 2.7 times the original, which likely increases our estimate by a similar multiplier. The concept of estimating a value for global ecosystem services is criticised by many economists. However, understanding the change in the value of soil for ecosystems services provision because of changes in soil management and use gives a valuation that is critical for policy decisions regarding soil security.

Quantifying Capability: GlobalSoilMap

GlobalSoilMap is an initiative of the Digital Soil Mapping Working Groups of the International Union of Soil Sciences (IUSS, digitalsoilmapping.org. Available at http://digitalsoilmapping.org/. Accessed 22 Oct 2015). It aims to meet the needs of the modelling community, farmers, land managers, policy developers and decision-makers, by creating a fine resolution (100 × 100 m grid) quantitative digital soil map of the world, using state-of-the-art and emerging technologies such as remote sensing, data mining and spatial databases. The data will be stored in a freely available distributed system with a set of standards for Web services. The approach has three components: digital soil mapping, recommendations for soil management and providing service to end users (Sanchez et al. Science 325, 2009). The project originated in 2006 as an effort to address the unmet need for quantitative answers to questions about soil-related issues such as soil carbon sequestration, the impact of soil carbon on biomass production and the change in soil status over time. To address such questions requires information about stores and fluxes of water, carbon, nutrients and solutes, in other words, functional properties of soils. The most significant stocks and flows are water including run-off, leaching, waterlogging and water available to plants, nutrients, carbon, solutes and acidification. Access to information about soil properties reduces risks in decision-making, but in order to understand and manage these risks, estimates of uncertainties in soil properties are required. Therefore, all quantitative data in the GlobalSoilMap will have an associated uncertainty. The project is facilitated by the synthesis of pedology, which focuses on soil processes, and pedometrics, which focuses on quantitative analyses.