ICARDA Caravan 4

The three Tunisian scientists with us that day had reason to celebrate. They worked with Mr. Najeh to develop the system, which is designed to supplement the threatened indigenous jessour system. It was devised by Dr Bellachheb Chehbani, who is a hydrologist, and the other two members of the team, agricultural economist Dr Mongi Sghaier and anthropologist Dr Noureddine Nasr. It is a multidisciplinary approach which ensures that whatever is developed is feasible, economic and transferrable.

The work is urgent in southern Tunisia. The region is dry, with a long-term rainfall of around 200mm. The landscape consists of undulating hills and mountains denuded of natural vegetation. Soils are poor and extremely shallow and rocky. Poverty is more prevalent in rural areas in Tunisia than it is in urban ones, and this is exacerbated by the low rainfall and poor soil--and, as IRA has established, by increasing pressure on marginal rangelands by overgrazing and accelerated soil erosion.

It is a vicious circle; as agricultural land is degraded and productivity drops, communities seek other ways to earn a living, and there is mass out-migration. The resulting labor shortage leads to neglected fields. Moreover, it causes a loss of indigenous skills which leads to further environmental damage.

The clearest example of this is that of jessour. This is an ancient system consisting of a series of stone and earth walls, called tabias, built across the stream beds of narrow valley watersheds. The tabias collect and retain soil washed down hillsides by torrential rains (that 200mm tends to come all at once), forming terraces in a stair-step fashion down the natural slope. Soil harvesting! The rainfall also collects on these steps and permits cultivation of olives and barley, the traditional crops, and sometimes apples, apricots, chickpea, faba bean, lentils, watermelons and vegetables. In the Matmata mountains, with their higher rainfall, the jessour system has allowed cultivation of figs, grapes and apples as well.

n a warm early-autumn morning, a group of scientists

and officials are standing in an olive grove in Gasre Jawame, near Benekhedeche in southern Tunisia. They are from several countries, and include three from Tunisia's Institut des Regions Arides (IRA) at nearby Medenine and another three from the Farm Resource Management Program of ICARDA. It's a pretty healthy olive grove; and, unusually, there are vegetables here too. In fact the farmer, Mr Najeh, is thinking of growing potatoes as well. That would certainly be breaking new ground for Gasre Jawame. How has he done it?

The answer lies just below the surface of the ground. The water is being carried direct to the roots of the trees and crops by polyurethane pipe, fed by gravity (the cistern is on the hillside above and is fed by surface run-off). The supply can be opened and closed with a tap Mr Najeh has installed in the grove. This prevents waste, as does the use of a closed below-ground system in which the water will not evaporate. Last but not least, taking the water straight to the root system is a boon for water-use efficiency.