IAEA Scientific Forum in Vienna
Nuclear Technologies Help to Reclaim Africa's "Green Desert" and National Saltlands
by Peter Rickwood, IAEA
Dramatic breakthroughs in reclaiming Africa's "green desert" and barren salt-stricken lands around the world are being driven by nuclear science, national scientists reported at an IAEA Scientific Forum in Vienna.
Africa's green desert is a 10 million square kilometre zone, encompassing 37 countries where the tsetse fly limits farmers from growing food, said Mr. John Kabayo of the African Union (formerly the Organization of African Unity).
Salt- damaged soil is a critical problem blighting millions of hectares of land in an arid zone around the world, some caused naturally but 77 million ha. as a result of human activity, said Mr. Mujtaba Naqvi of Pakistan.
The two scientists were addressing the first of a two-day Scientific Forum, held in conjunction with the IAEA General Conference at the Austria Center, to raise awareness about productive nuclear technologies that may not be well known to the public.
The impact of the tsetse fly in Africa "is difficult to exaggerate," Mr. Kabayo told the Forum, which is being attended by scientists, government officials, and development experts from around the world. "The problem was regarded as unsolvable".
The fly spreads sleeping sickness, that in some African countries has become the leading cause of death, and carries a disease that kills cattle, denying farmers their power to plough fields, as well as supply food and manure.
But the tsetse fly was eradicated from Zanzibar in 1997, using an environmentally friendly insect control method, developed by IAEA scientists, that exposes mass- reared male tsetse flies to low radiation doses that sterilise them. The sterile males, who continue to mate with fertile females, are released over an extended period of time and eventually overwhelm the wild population. The method of control is known as the sterile insect technique.
On 5 October, said Mr. Kabayo, the Pan-Africa Tsetse and Trypanosomosis Eradication Campaign, using the sterile insect technique, will be officially launched by the African Union in Burkina Faso.
The Food and Agricultural Organization (FAO) estimates that poor agricultural practices has left 77 million ha. of land damaged by salt.
Since 1997 the IAEA has been supporting a model project that is demonstrating it can be successfully revived.
In nine countries in North Africa, the Middle East, and Pakistan, crops are being cultivated on land laid waste by
salt in an IAEA-supported project coordinated by Mr. Naqvi.
There are a large number of plants that can survive, even thrive, in conditions of high salinity, he said, even when irrigated with brackish, or salty, water.
Their growth offers a number of benefits:
- green cover
- conservation of moisture
- a brake on soil erosion and desertification
- the plants can also be used for food, forage, fibre, fuel, fertilizer (compost) and feedstock for industry
techniques, neutron moisture gauges and isotope hydrology, are
used to monitor the amount of saline groundwater that is used
for irrigation and determine its passage under the ground
"You have to manage the irrigation so that you don't
build up salt," Mr. Naqvi said. Excess salt found in soil is often the result of such a large amount of water being used that natural salts in it aren't dissolved out, he said.
"We have done demonstrations on 10 ha sites, farmers have seen the process and the knowledge is being passed onto them," he said.
"We have shown that it is possible to grow economically useful plants such as barley, varieties of wheat, dates, and olives, in saline waste land using saline ground water. In most cases this is an indicator of how large an area can be used. Nowhere did we get a report that soil was destroyed because we were using saline ground water. We feel that if the government encourages farmers the technique will just take off and have its own momentum."