The following review article was written by Bruce Knight for the March 2013 edition of Crop Scene.
Have we lost control of the world’s soil resource?
The science of managing the soil in order to improve crop yields was the first of the agricultural
sciences to really make an impact. Charles ‘Turnip’ Townshend, although not a scientist,
recognised the importance of looking after the soil as early as the beginning of the 18 th century.
Townshend’s Norfolk four crop rotation soon showed the benefit in terms of yields. Townshend
was perhaps unwittingly one of the first to develop a form of sustainable agriculture.
Although soil science has made significant progress over the centuries towards our
understanding of the role of soil, it is today a relatively poor relation compared with the other
crop related sciences. Perhaps one explanation is that unlike the plant sciences there is not the
same opportunity for research based companies to invest in discovery leading to intellectual
property and financial return.
However given today’s challenge
of meeting global food needs
sustainably from the same, or
even less, land area a number of
observers and a few policy
makers
recognise
that
investment in soil science and
better soil management is long
overdue.
90% of world food production
depends on the soil. It is also
critical for the support of
ecosystems, conservation of
biodiversity
and
influencing
climate change impact.
Photo via Time Magazine (Shutterstock)
New initiative from Potsdam
An organisation that is addressing and communicating about the issues relating to soil is the
Institute for Advancement for Sustainability Studies, IASS. With support from the Federal
German Government the IASS was founded in Potsdam, in February, 2009. Researchers at the
IASS aim to address the various dimensions of sustainability and to act as a platform for
science and a link between research, politics, and the economy and to help shape public opinion.
Soil is high on the agenda of the IASS and in 2011 a Global Soil Forum, GSF, was formed. The
remit of the GSF is to act as a voice in the national and international policy debate, advocating
for soil management approaches that ’contribute to achieving sustainable development to this
finite resource.’
The first high profile event organised by the GSF was the Global Soil Week. More than 400
representatives of governments, scientists, international organisations, business and civil
society met in Berlin in November 2012 to consider the theme 'Soils for Life'.
The background to the crisis facing soils globally is alarming. Every minute, 23 hectares of land
face desertification, 5.5 hectares of land are transformed by urban encroachment (severely
disturbing soil functions), and 10 hectares of soil are degraded, causing the soil to lose the
capacity to support ecosystem functions.
Professor Klaus Töpfer, chairman of the Global Soil Forum, was reported as saying: “Without
fertile soils, food security, poverty alleviation and climate change, mitigation and adaptation will
not be achieved. The Global Soil Week, being the first of its kind, requests politicians, land
managers and civil society to address soils and land management as a core priority area now.”
Coming out of the event it was concluded that urgent and consolidated action was needed to
strengthen science and technology, build partnerships for change and raise awareness about the
issue. Key actions were proposed including facilitating the science policy–public interface and
making the Global Soil Week a continuous process. It was also agreed to develop an agenda for
action calling on multilevel governance to achieve zero net land and soil degradation.
An extreme opinion from down under
At the other end of the world The World Economic Forum recently reported on the implications
of soil erosion as described by Professor John Crawford, chair in Sustainable Agriculture at the
University of Sydney. Professor Crawford’s interests are multidisciplinary. When working in
the UK he headed up a committee responsible for the allocation of research in sustainable
agriculture as well as diet and health.
The World Economic Forum is described as an independent international organisation committed
to improving the state of the world by engaging business, political, academic and other leaders
of society to shape global, regional and industry agendas.
Professor Crawford paints a particularly stark view of the state of soils globally. His comments
were reported through the World Economic Forum by a series of questions and answers:
•
Is soil really in danger of running out?
A rough calculation of current rates of soil degradation suggests we have about 60 years of
topsoil left. Some 40% of soil used for agriculture around the world is classed as either
degraded or seriously degraded – the latter means that 70% of the topsoil, the layer allowing
plants to grow, is gone. Because of various farming methods that strip the soil of carbon and
make it less robust as well as weaker in nutrients, soil is being lost at between 10 and 40 times
the rate at which it can be naturally replenished. Even the well-maintained farming land in
Europe, is being lost at unsustainable rates.
•
Why haven’t we heard more about this?
Probably because soil isn’t sexy. People don’t always think about how it’s connected with so many
other things: health, the environment, security, climate, water. For example, agriculture
accounts for 70% of our fresh water use; we pour most of our water straight onto the ground.
If soil is not fit for purpose, that water will be wasted because it washes right through
degraded soil and past the root system. Given the enormous potential for conflict over water in
the next 20-30 years, you don’t want to exacerbate things by continuing to damage the soil,
which is exactly what’s happening now.
•
How does soil erosion happen?
Soil is a living material: if you hold a handful of soil, there will be more microorganisms in there
than the number of people who have ever lived on the planet. These microbes recycle organic
material, which underpins the cycle of life on earth, and also engineer the soil on a tiny level to
make it more resilient and better at holding on to water.
Microbes need carbon for food, but carbon is being lost from the soil in a number of ways:
Stubble is no longer left on the field after harvest; carbon is lost by too much disturbance of
the soil by over-ploughing and by the misuse of certain fertilisers and overgrazing removes a
source of carbon from plant growth.
•
What happens if this isn’t addressed?
There are two key issues. One is the loss of soil productivity. Under a business as usual scenario,
degraded soil will mean that we will produce 30% less food over the next 20-50 years. This is
against a background of projected demand requiring us to grow 50% more food as the population
grows and wealthier people in countries like China and India eat more meat.
Second, water will reach a crisis point. This issue is already causing conflicts in India, China,
Pakistan and the Middle East and, before climate change and food security really hit us, the
next wars are likely to be fought over unsustainable irrigation. Even moderately degraded soil
will hold less than half of the water than healthy soil in the same location.
•
Who will be impacted the most?
Soil erosion is most serious in China, Africa, India and parts of South America. If the food
supply goes down, then obviously, the price goes up. The crisis points will hit the poorest
countries hardest, in particular those which rely on imports: Egypt, for example, is almost
entirely dependent on imports of wheat.
Professor Crawford further argued that many of the world’s areas of conflict can be attributed
to mismanaged agriculture. He considers that governments are subsidising unsustainable food
production systems and that soil management is not costed into the cost of food. Farmers don’t
have the financial capacity to invest in their soil to turn the situation around. He also questioned
the role of crop breeding. Modern wheat varieties, have half the micronutrients of older
strains. The focus has been on breeding high-yield crops which can survive on degraded soil, so
it’s hardly surprising that 60% of the world’s population is deficient in nutrients like iron. If it’s
not in the soil, it’s not in our food.
•
What should be done about this?
Professor Crawford believes that progress is technically quite straightforward. His radical
suggestions included:
- A focus on getting carbon back into the soil, by reversing bad farming practices like tillage,
nutrient mismanagement, removing stubble and over-grazing.
- Consider using human waste from cities as fertiliser, instead of just flushing it all out to sea.
- Breeding targets need to focus more on human nutrition as well as productivity, and on traits
that improve the soil.
- Find new ways of bringing together scientists and farmers to harness the expertise of both.
- From a policy standpoint, probably the most important thing is to find pricing mechanisms that
take into account the environmental, health and other costs of a broken system.
- Farmers need to be appropriately rewarded for regenerating the environment and producing
food that supports a healthier society.
- Recognise that this is a global problem that would benefit from a global approach. There is not
time to reinvent the wheel in each country. It takes decades to regenerate soil.
A final observation from Professor Crawford was: “I find it quite ironic that while the Mars
Curiosity Rover is poking around looking for life in Martian soil, we’re in the process of
extinguishing life in our own.”
Professor Crawford may be overstating the role of soil and its impact on global issues. But it is
clear that greater investment in soil science and from this better soil management is urgently
called for.
*****