Greening the Negev – Lessons from the Sahel

by Maskil on September 29, 2009

Tolotama reforestation, Burkina Faso.

Image via Wikipedia

The latest BBC Earth Report (entitled Down to Earth) gave a fascinating glimpse into local efforts to re-green the West African portion of the Sahel.  It described three of the techniques being used to achieve this (diguettes, so-called half-moons and zai).  From the transcript of the documentary:

The techniques used are simple but effective. One such practice is the “diguettes” – low dry stonewalls to retain water and stop rainfall runoff.

Ouedraogo Boureima: Working with stone lines is helpful because if the land is bare, the rain water runs off and carries away the good soil and seeds we’ve planted. By planting new trees, when they grow, it helps stabilise the soil.

Mathieu Ouedraogo: This is a traditional method we’ve adapted and it consists of measuring the levels. The technique of piling stones to make stone barriers has existed for millennia. But this adapted technique is primarily from Burkina Faso.

The farmers have refined the old technique by charting a level line across the face of the slope then placing the stones to make a barrier at an even height along the length of the field.

Once the fields have been stabilised by the “diguettes” the farmers use a different technique to protect the growth of their crop seedlings. They’ll make a “half moon.” It’s cut from the hard soil and filled with manure and vegetation, allowing water to be retained long enough to encourage new growth. It helps to protect the crops and soil from being blown away in the dry season. Again it’s a simple, effective technique, but in 50 degree heat only two “half moons” can be dug a day. “Zai” – another ancient technique Mathieu likes – is easier. Small holes are dug and filled with dung and seeds. The microorganisms within the dung create the best environment for the seeds in this harsh dry soil until the rains come.

These techniques – traditional, but updated for modern conditions and given a scientific underpinning – resemble in some ways the techniques adopted by the JNF in its efforts to green (or re-green?) the Negev Desert in Israel – limans and savannization.  (For those who are interested, please see the descriptions of these techniques below, drawn from different sources.)

While the KKL-JNF no doubt still has much to teach Africa regarding desert reclamation, perhaps some of these age-old African techniques can be modified and applied to the Negev, particularly if ways can be found to mechanise them, or at least make them somewhat less labour-intensive.  (Labour is far more plentiful in Africa, and much less of a social issue than in Israel, unless we can find ways to reignite enthusiasm for a Kibbutz Volunteer culture.)

The writing is on the wall for the settlements in Judea and Samaria (the West Bank).  The settlement impulse will need to be diverted back into Little Israel (mainly the Galilee and Negev), and the KKL-JNF will need all the resources it can muster (including intellectual and technical) in order for the Negev to support a far higher density of both biomass and human population.

Limans

Liman is a Greek word meaning “port”. But in Environmental preservation work, limans are group of trees planted at low lying points in various locations in the Negev. These small groves are surrounded by earthen embankments that create a kind of mini-watershed within them. Winter rainfall flows from the basin into the liman, providing all the water the trees need without further irrigation. Since Negev summers are rainless, the soil of the liman must be sufficiently deep to soak up the water needed to nourish the trees from one winter to the next. Nevertheless the trees selected for planting in the liman are suitable for arid land life.

Savannization

Israel has developed new afforestation practices for semi-arid and arid regions, the most famous of which is called savannization. This technique is based on harvesting of surface run-off through contour furrows [on?] hillsides afforested with trees. Savannization has proven to prevent desertification and increase productivity and biodiversity without external resource enrichment. It was demonstrated that savannization reduces flash floods and their consequent soil erosion, and increases the overall productivity of semiarid soils.

Links/Reading/Resources:

I found the following documents and resources useful in understanding the approach of Israel and the KKL-JNF to combating desertification and greening arid zones (such as the Negev).

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