The supply of Soil Functions in European Soils
Wageningen University, Netherlands
Why do our Soils matter?
The Sustainable Development Goals were established in 2015 by the United Nations to to end poverty, protect the planet, and ensure prosperity for all. There are 17 goals in total and each goal has targets to be reached over the next 15 years. Recently the Sustainable Development Goals were rearranged by the Stockholm Resilience Centre to highlight the importance of soil, land, water and climate as they underpin all the remaining development goals. Soil is essential for society as a whole, as it provides us with our food, raw materials for fuel, clothing, as well as an environment in which we can flourish as a cultural society.
Soil is specifically mentioned in four of the 17 Goals only, these include; No. 2 dedicated to Zero Hunger in the World, No. 3 on Good Health and Well-being, No. 12 on Sustainable Production and Consumption and No. 15 Life on Land. While soil was not considered in the original text of the goal No. 13 Climate Action, the agreements made at the Paris Climate COP 21, in November 2015 highlighted the role of soils in Climate Action as well, in particular for carbon sequestration.
In Europe, there has traditionally been a focus on soil functions and threats, rather than soil health. In 2006, the Thematic Strategy for Soil Protection was developed looking at the role of soils in society. This document highlighted the main soil threats (compaction, erosion, salinity, acidification, landslides, loss of biodiversity, sealing, decline in organic matter and contamination) and also the positive message of the functions that soil supplies to society (substrate for plant growth, habitat for biodiversity, nutrient cycling, carbon sequestration and cycling, water quality and regulation, platform for infrastructure and store for archaeology). Following the Soil Strategy, a European Legislation was developed looking at minimising the threats to soils and enhancing soil protection. This was named The Soil Framework Directive. However, this Directive was never accepted by all member states, with the focus on soil threats and was removed from policy discussions in 2014.
Therefore, the approach now is to look at the role of soils from a positive perspective and show what soils can do for us as a society and how we can sustainably manage this precious resource.
What do we want from our soils?
We must first decide what are the main soil functions that we want the soil to deliver? In an agricultural context, this is primarily to provide food, fibre and fuel – whether that is cereals, beef, milk, biomass crops, or wood etc. However, in the production of food, we must also ensure that we do not diminish the capacity of the soil to also carry out the other soil functions necessary to ensure sustainable food production. This dual optimisation of both agricultural supply and the capacity of the soil to meet environmental requirements can be at times challenging.
What do we mean by soil functions? In agricultural systems, we consider the following functions that the soil supplies:
Primary productivity - providing maintenance for the growth of food. feed and fibre, this includes; root support, water and air through the soil structure.
Cycling of external nutrients – capacity of a soil to absorb and store and slowly release nutrients to crops over time.
Water purification – ability of a soil to remove excess nutrients and pollutants from water before it reaches the water source.
Carbon storage and cycling – capture and cycling of carbon sources from the atmosphere and plants, that carbon then provides strength to the soil structure and nutrient reserve.
Biological habitat – provides a home to the largest diversity of biological organisms on the planet. These soil organisms drive most of the processes that take place in soil.
Managing our soils lives at the heart of farming systems. So understanding what functions our soils are best at delivering is essential to get the best from our land. While all soils are capable of delivering on all functions, some soils are better than others at specific soil functions. That is traditionally how we decided where to grow which crops, which areas to leave to nature and which soils are suited more grassed based or forest land use types.
Managing our soils across a range of scales
Every day, farmers make decisions on how they manage their land and soil, including decisions on fertilisation, ploughing, reseeding, weight of tractors, application of pesticides, herbicides and insecticides, etc. At the same time, national and European policy makers make long-term decisions on how to manage their soil resources at larger scales, such as how to work towards meeting greenhouse gas emission targets through optimising carbon sequestration in soils.
Therefore, the contemporary challenge for researchers and stakeholders is to link the decision making on land management across scales, so that the practicalities of how farmers make decisions on a daily basis is reflected in policy formation.
We cannot expect all soil functions to be delivered simultaneously to optimal capacity, but with careful decision making we can optimise our soils to provide multiple functions. In reality not all functions can be optimised to their full capacity at the same time, as the conditions required to deliver one function may be in contrast to those to deliver another function. A good example of this, is the requirement for nutrient cycling which may compete with the with the ability of the soil to support the function habitat for biodiversity, where external inputs include sewage sludge derived materials, which can have a significant impact on the soil biology. However, in many cases multiple functions can work in synergy together and in most scenarios three out of five soil functions can be optimised together.
Mapping and Assessing Ecosystem Services:
In addition to the soil functions approach, there is an increasing focus on mapping and assessing soil based ecosystem services. The Food and Agriculture Organisation of the United Nations (FAO) defines soil based ecosystem services as; “Ecosystem services are a way of putting a value on biodiversity by looking at what it does and how we value the function that the soil performs”.
MAES (Mapping and Assessing Ecosystem Services) is part of the Action 5 deliverable of the Biodiversity Strategy. The Directorate General for the Environment of the European Commission are currently in a process of developing guidelines for the mapping and assessing of soil ecosystem services. These guidelines will be provided to Member States within Europe, who will be asked to identify and map the soil ecosystem services within their country.
What the future holds for soils in Europe
While there is no current legislation for the protection of soils in Europe, there is certainly increasing recognition of the role of soils in society. There is a lot of on-going research which is identifying the role of soil functions and how we can optimise the supply of these functions in a sustainable manner. One such project is the LANDMARK project, funded by the Horizon 2020 European Research Funding. This includes representative scientists, advisors, land managers, and policy makers from across Europe, China and Brazil. This project is looking at the role of soil functions at three different scales:
Local scale – to help farmers optimise the soil multi-functionality on their farms
Regional scale – to identify how soil functions vary across the different climatic zones of Europe and how we measure soil functions.
An assessment of policies that can ensure that we ‘make the most of our land’, from both an agronomic and environmental point of view at a global scale.
For more information on LANDMARK see: http://landmark2020.eu/
Follow LANDMARK on Twitter: @Landmark2020