The IAEA Mass Spectrometry Laboratory in Seibersdorf,
Saline soils: Why Nuclear?
The IAEA project on saline soils illustrates how the use of atoms in agriculture
can help to prevent the degradation of farmlands and point the way towards
more productive harvests. The project combines several proven nuclear techniques
and applications to provide key pieces of information to soil scientists,
farmers, land managers, and irrigation specialists.
- Neutron moisture gauges, or probes, are being used to monitor soil
conditions and irrigation practices. One result is that irrigation can
be better managed -- only needed amounts of irrigated water are applied
and salt accumulation is better controlled.
- Chemical elements called isotopes are being used for water, soil, and
plant studies. Both stable and radioactive isotopes help scientists analyze
groundwater resources, providing information about the quality and quantity
of groundwater recharge and thus the sustainability of its use. Other
isotopes can be used for "labelling" plants to trace the pathways of
elements such as carbon and nitrogen that circulate from the atmosphere
to plants to soil and again into the atmosphere. (Also see, Partners
in the Lab.) Their study can provide information on the effect of
plants on soil structure and fertility, for example. Some isotopes, such
as those of chlorine, can be used to monitor the movement of saline water,
yielding valuable information to guide sustainable farming practices
on saline lands.
- For water studies, isotopes of hydrogen and oxygen are of special interest.
Deuterium, or hydrogen-2, and oxygen-18 are heavier and much rarer than
the more abundant isotopes hydrogen-1 and oxygen-16. Tritium, or hydrogen-3,
is even rarer and radioactive. Rising water vapour from oceans has a
lower concentration of the heavy isotopes than seawater. This means that
when it rains, the heavy isotopes rain out first, and that the precipitation
changes isotopically as clouds move inland. In the process, water acquires
individual and characteristic "fingerprints" in different environments.
In groundwater studies, the decay of tritium dates the groundwater over
decades; radiocarbon in dissolved lime can "date" many millenia. When
hydrologists analyze data from water samples, they gain historical insights
into the water source's dynamic lifespan, including its age, origin,
and transport processes, that help shape decisions about how the water
is used in the future.
Taken together, nuclear and isotopic techniques have become keys of efforts
to fight the environmental degradation of arable lands. The tools are safe,
precise, affordable, and sometimes the only means to study the complex
interrelationships between soils, water, and plants.
Agricultural development is a central component of the IAEA's technical
cooperation programme, which is placing renewed emphasis on demonstrating
innovative solutions for conservation and agricultural production of marginal
lands. An overriding goal is to strengthen national capabilities for implementing
common policies and international protocols. Projects particularly seek
to encourage and broaden technical cooperation among developing countries
to tap regional expertise and resources in applying tools of nuclear science
and technology to shared problems.
Through technical cooperation and related channels, the IAEA is seeking
to strengthen its collaboration with international and regional organizations
committed to sustainable agricultural development. A central role is played
by the United Nations Secretariat
of the Convention to Combat Desertification, which helps to mobilize
resources to support national and international actions against land degradation.
The IAEA's scientific and technological resources can contribute in key
ways to overcoming the challenges ahead through stronger partnerships and
well-defined cooperative programmes.