Improving on an Ancient Way to Harvest Rainwater collect, between, another, English, describe

李武军

I'm Faith Lapidus with the VOA Special English Agriculture Report.
A few months ago, we talked about a system to harvest rainwater. The water travels from the roofs of buildings through pipes into a storage tank. Now we describe another system to collect rainwater, this time between mountains.
Earth dams capture the water for fields planted on a valley floor. It is an ancient idea, known as a jessour. But scientists and farmers have developed ways to improve on tradition.
A jessour starts with an earth dam high up in the valley. The dam captures rain, and the water pours over a spillway into a field below. Farther down the valley, another earth dam separates the first field from the next. This system of fields, bordered by dams, continues all the way down the valley.
Heavy rains, however, can damage the dams. Also, rocks and soil washed downhill can fill spillways and cause the fields to flood.
Farmers in Tunisia have used jessours since ancient times. The average rainfall in most of the country is less than two hundred millimeters per year. UNESCO has supported studies of efforts to improve jessours in Tunisia. UNESCO is the United Nations Educational, Scientific and Cultural Organization.
It says a solution to weak dams made of earth is to build dams out of concrete for greater strength. Another measure to improve jessours is known as a "buried stone pocket." This is what some farmers do:
First, they dig a planting area. They lay stones in a small circle about forty centimeters below the surface. They leave an opening in the center. The farmers then stand a plastic pipe between the stones and cover the stones with soil.
Next, they plant a young tree in the center. They give the tree water through the pipe. That way, the water goes directly to the roots.
Farmers in Tunisia have traditionally used jessours to grow olive, fig and palm trees. But some farmers have started to grow other kinds of fruits and vegetables. Demand has increased from cities and popular holiday areas. UNESCO says some farmers now have more than ten kinds of fruit trees in their fields.
Farmers have found creative ways to grow apples, pears, peaches, almonds and other crops in jessours. These new ideas have helped make this labor-intensive method of farming more worth the effort.
This VOA Special English Agriculture Report was written by Mario Ritter. Our reports are online at WWW.51VOA.COM. I'm Faith Lapidus.