December 5th has been declared World Soil Day by the UN General Assembly, and this year it will mark the conclusion of the International Year of Soils, which is intended to increase awareness and understanding of the importance of soil for food security and essential ecosystem functions.
For over 40 years as an international soil scientist, I have been hearing more and more what I call “The Soil Scientists’ Lament” – the cry that “soils are neglected”, “soils are under-valued”, “inaction on soil degradation is costing hundreds of billions of dollars per year”, “but those who make public policy are not listening to us”.
The International Year of Soils has undoubtedly served to bring greater public attention to the importance of soil health, but despite these efforts is anyone really listening? Will throwing more numbers at policy makers on the cost of soil degradation and inaction make a difference? Will the Soil Scientists’ Lament continue unabated?
Soil health from the perspective of a soil scientist
It is true that the functions that soils provide and their degradation are not very visible to the public – what is happening to the soil underfoot is not as visible as say smog due to atmospheric pollution, or algal blooms caused by excess nutrients entering our water bodies. Changes in soil properties also typically happen slowly over a number of years and are not easy to see.
And yet soils form the very foundation for net primary production – for our harvests of food, fibre, feed, and timber – and more. Soils perform a multitude of services that support and regulate production and our ecosystems. One of the critical ones, which is relevant to the upcoming negotiations in Paris, is regulation of our climate through greenhouse gas retention.
Soils regulate water flows in our landscapes, including river flows, flooding and buffering droughts; provide water quality control through filtering, recycling and detoxification; and control erosion and sedimentation. They play a fundamental role in regulating water, nutrient and energy cycles. In addition, soils provide a habitat for biodiversity, regulating pests and diseases, and also provide an important genetic resource for antibiotics and future medicines.
The thin layer of topsoil is most critical to providing ecosystem functions, but is easily eroded or degraded, and yet can take thousands of years to regenerate. Soil is essentially a non-renewable resource. The need for and benefits of sustainable soil management are obvious to any soil scientist, and so why are they not being heeded and translated into policy action?
Let us look at the problem from the view of government policy makers
They have a finite amount of funding to allocate among different development priorities and are interested in interventions that achieve multiple human well being and environmental outcomes.Rational decision making would lead them to implement a portfolio of interventions that would best achieve the set of desired outcomes.
What soil scientists need to be concerned with is what type of soil information would add valueto this type of decision dilemma and how it can be integrated into decision making.
Soil science research has built up detailed knowledge of soil processes and the distribution of types of soils. But is cannot easily tell a decision maker, for example, what are the on-site and off-site economic implications of applying a given land use practice in terms of soil functionsover the next 20 years. Or whether a given practice could reduce the risk of crop failure due to soil-borne diseases from 1 in 10 years to say 1 in 20 years. Or what is the economic benefit of increasing soil organic matter by a given amount considering multiple soil functions.
Soil scientists need to pair up with decision scientists
Decision scientists quantitatively analyse the costs, benefits and risks associated with decisions,and engage with stakeholders in a transdisciplinary effort if they are to have impact. Decision science can facilitate soil scientists to overcome a fear of making projections on the impact of soil management on large scale processes, to faithfully represent the uncertainty in their current knowledge, and pinpoint where further knowledge could make a difference.
A first area for attention is for soil scientists to gain a better understanding of the real decision dilemmas facing policy makers and stakeholders, rather than starting with their own research interests and then seeking applications.
For example, there is much current research interest among the soil science community on increasing the accuracy of measuring and mapping soil carbon stocks. But this is done without systematic analysis of whether this additional accuracy is the critical information actually needed to improve real decisions facing policy makers, such as on the best strategies for shifting to low carbon emission land uses.
A second area for attention is for soil scientists to embrace uncertainty. Currently when soil scientists do have the courage to make projections on the impact of soil management on productivity and ecosystem services, their models usually ignore uncertainty. This presents decision makers with a false sense of confidence and actually undermines credibility. Decision science provides the tools to combine both expert knowledge and the best available data, encode it in the form of probability distributions, and apply it to improve decision quality.
By including uncertainty, decision analysis enables scientists to breakthrough three important barriers:
- It encourages scientists to make projections on things that they would otherwise be reticent to make. They may be very uncertain about a quantity or relationship but they put ranges on it. In fact, decision analysts train scientists to reduce common biases in subjective probability estimation. Even when uncertainty is high, including this information can vastly improve intervention decisions, as opposed to omitting it altogether.
- Including uncertainty allows risk for decision makers to be made explicit. When evaluating intervention options, rational policy decision making must consider risk, not only average level of returns. Risk is also central to concerns over sustainability and resilience, which are key considerations for agricultural and environmental management.
- Including uncertainty allows calculation of the value of information – curiously, a quantity not widely known among scientists. Information value is high where reducing uncertainty will make a large difference to outcomes and could change the decision. Knowing the value of information guides scientists on what additional information is needed to narrow uncertainty and enable a good decision to be made.
The cure for the Soil Scientists’ Lament, then, is to integrate and build capacity in decision sciences as a core component of research. This is likely to be true in many other disciplines as well if they seek development impacts.