Rome, Italy
July 21, 2008
A new database on the world’s
soils improves knowledge of the current and future land
productivity as well as the present carbon storage and carbon
sequestration potential of the world’s soils. It helps to
identify land and water limitations, and assist in assessing the
risks of land degradation, particularly soil erosion risks, said
FAO today.
Derived from the soil database, FAO
has produced a global Carbon Gap Map that allows for the
identification of areas where soil carbon storage is greatest
and the physical potential for billions of tons of additional
carbon to be sequestrated in degraded soils.
Soil information has often been the one missing information
layer, the absence of which has added to the uncertainties of
predicting the potential for and constraints to food and fibre
production as well as the capacity of soils to hold carbon and
to act as a sink.
Until now, most efforts to use agriculture to manage greenhouse
gases have involved above-ground sequestration, primarily
through planting trees, since the amount of carbon that can be
sequestered in this way is substantial. However, there is also
growing interest in finding ways to increase carbon
sequestration in soils. Soils are presumed to be the largest
carbon reservoir of the terrestrial carbon cycle, although
estimates of their magnitude vary widely. Soil can be a source
or a sink for green house gases depending on land use
management. For long-term sequestration, organic carbon must be
stored in forms and in locations in the soil profile with slow
turnover.
“The chemical and physical properties of soils also help to
determine specific information about how well a soil will
perform as a filter of wastes, as a home to organisms, as a
location for buildings and as pool for carbon. The more
information we have about soil properties, the more we can
evaluate the quality of our natural resources all over the world
and their potential to produce food now and in future scenarios
of climate change” said Alexander Muller, FAO Assistant Director
General for Natural Resources and Environment Management.
“Soil characterization data are a key piece of the picture of
how an ecosystem work,” said Freddy Nachtergaele, FAO soil
expert. “Soil properties also tell us whether the soil has the
potential to store enough water to keep plants growing through a
drought or to withstand a flood. Farmers’ knowledge of soil
properties also forms the basis of managing fertilizer
application efficiently thus reducing avoidable nutrient losses
to the environment.”
Land Potential Assessment
FAO and the International Institute for Applied Systems Analysis
combined recent regional and national updates of soil
information worldwide and incorporated the FAO-UNESCO Soil Map
of the World into a new Harmonized World Soil Database (HWSD).
Other partners such as The European Soil Bureau Network; the
Institute of Soil Science of the Chinese Academy of Sciences and
ISRIC World Soils contributed significantly to the information.
Soils as carbon stores
Different soils have different capacities to act as a store for
carbon which has direct implications for capturing greenhouse
gases. The world's soils hold more organic carbon (1500 Gt) than
the atmosphere that contains about half this amount as CO2 (720
Gt), and the vegetation (600 Gt) combined. Thus, relatively
small changes in the flow of carbon into or out of soils have
significant effect on a global scale. In addition to predicting
the effect of changing rainfall patterns under climate change
scenarios, scientists require information on soil moisture
storage capacities which are provided by this database.
The HWSD provides improved soil information worldwide
particularly needed in the context of the Climate Change
Convention and post Kyoto Protocol instruments for soil carbon
measurements and carbon trading. It can also be used by
agronomists, farm experts and scientists in planning the
sustainable development of agricultural production and will
improve land degradation assessments, environmental impact
studies and sustainable land management options.
The database will also serve to guide policies aimed at
addressing land competition issues concerning food, energy and
biodiversity. |
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