Preserving Soils
The Degradation and Future Preservation of Soils
Soils are one of the world’s most precious commodities.
It is probably safe to say that without soils there would be no
support for life on this planet. The fact that the world’s
population is forecast to rise to from its current 5.8 billion
to 8 billion by 2025, with a huge increase in demand for food highlights
the reason why soils need to be preserved.
For the past few decades there has often been a lack of appreciation
of why we need to preserve soils. During this period there have
been numerous examples of damage to world soils, some of which
are now irreparable. Some examples of the problems that face soils
include:
Soil erosion and desertification: This is a major problem
in many countries in the world, particularly, but not solely, in
the drier, warmer parts of the world. Desertification currently
affects about one-sixth of the world’s population and a quarter
of the world’s land. Six to seven million acres are lost
annually to soil erosion and both these processes continue to increase
despite the many attempts made to introduce measures to stop or
reduce erosion. It is a major threat to world soils and because
of this there have been major initiatives to reduce desertification
and erosion, including those by UNESCO, FAO, and the European and
US Conservation bodies. However factors such as the need to increase
food production and the likely impacts of global climate change
are likely to make the fight against erosion and desertification
increasingly difficult.
Salinisation and alkalisation: It is estimated that over
20 million hectares of land is affected by salinisation and alkalisation,
again mainly the drier more arid areas of the world. Salts may
be deposited in a number of ways; by winds coming in from the oceans,
by use of irrigation with salt-containing water, and by salt accumulation
in low-lying spots in the landscape as the climate varies. Like
erosion and desertification, it is only in recent years that the
problem has been recognised as a serious one and steps taken to
reduce its spread. However, once accumulated in the soil it is
a difficult and long-term problem to get rid of it.
Impact of intensive agriculture: The last four decades
has seen a major increase in intensive agriculture in the bid to
feed the world population more efficiently than ever before. In
many countries, particularly the more developed countries, this
intensification of agriculture has led to the use of more and heavier
machinery, deforestation and clearing of land for use in cultivation.
This has led to several problems including loss of organic matter,
soil compaction and damage to soil physical properties generally,
over-application of many nutrients in the form of fertilisers and
pesticides, leading to problems with contamination of water supplies,
potential loss of soil fauna and flora, such an essential part
of a healthy soil, amongst others.
Urbanisation and land contamination: Urbanisation and
the sealing of soils by infrastructures (i.e. building structures
on top of soil) represents a significant loss of soil, particularly
because the loss becomes more or less permanent. In developed countries
there is a loss of about 1 per cent of land to urbanisation each
decade.
The 18th and 19th centuries also saw enormous industrial expansion
in many parts of the world with two major consequences for soils.
Firstly, the widespread burning of fossil fuels in industry has
led to widespread acidification of rainwater; for many decades
soils of Western Europe have been leached by rainwater with a ph
of about 4, i.e. strongly acidic. The second legacy of industry
is contaminated land, the extent and effects of which are still
not fully known.
Thus in the last few decades there have been many pressures put
on global soils and already significant and irrecoverable damages
have been done. We now need to move forward with much more awareness
about the damage that has been caused to global soil resources
and with a realistic programme for the preservation and protection
of this unique natural entity, soil. Already there is increasing
awareness of soil erosion and desertification in many countries
and measures in place to protect soils from future damage. But
in some environments, such as parts of Africa, the soil is a fragile
entity, it lacks a robust nature, and therefore particular attention
needs to be paid to its management and to ensuring that the management
is clearly in tune with the soil. This is a real challenge but
unless this challenge is accepted the route to future use of many
of these soils could become a dead-end, with catastrophic results
for many communities. Many of the techniques needing to be applied
are already well known, the challenge will be to integrate them
into land use practice, particularly in a likely changing climate.
The problems of salinisation and alkalisation continue and are
reversible only with great difficulty. As with erosion and desertification,
the causes are generally well established but very difficult and
costly to remediate and solve. It is important that the problem
does not continue to increase and there therefore needs to be better
communication between the land user and those that advise them
about their soils, and between policy makers and environmental
scientists.
The problems associated with intensification of agriculture outlined
above are more readily treatable. The causes of the problems are
well established and already in many developed countries actions
are being taken to work more in harmony with the soil. Some of
the problems may take just a few years to improve upon whereas
others, e.g., low contents of organic matter and nitrates moving
downwards into groundwater, may take decades to remediate.
There need to be national and international plans for urbanisation
that take into consideration the importance of protecting soils.
Everyone is aware of the need to build more houses and to improve
infrastructures but this process needs much more careful planning
than before, with the need to preserve and protect soils in mind.
Already we are much more aware of the problems of soil contamination
and the difficulties that arise from 'post-industrial' use contaminated
land. Many countries now have safeguards in place to help to prevent
soil contamination. Clean up of the contaminated land, however,
remains a problem both technically and financially.
Soils have suffered from several decades of damage on a scale
that we must not allow to continue. The reasons for this neglect
are many. But if we are to ensure the protection of global soils
into the future there must be much stronger awareness and acceptability
among the public, policy makers and land users of the need to preserve
soils for current and future generations. To ensure that this takes
place it will be important that World Organisations and National
Governments ensure there are adequate measures in place to give
a much needed emphasis on soils and their future protection.
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