Researchers aim to fight the Sahara with the sisal plant

How can desert encroachment be halted? Algeria is having trouble finding the answer, and researchers from all sectors are being called to the rescue to try to relaunch past efforts that did not bring the hoped-for solutions.

Algeria, the largest country in Africa in terms of land mass, is faced with a serious problem: its desert, the Sahara – one of the biggest in the world, is continuously spreading north.

It is driving populations to migrate towards the coastal regions and, at the same time, reducing agricultural areas, putting food safety and especially biodiversity at risk.

In the 1970s, the Algerian government launched a vast tree-planting programme, ‘barrage vert’, or ‘green barricade’.

This was a belt of forest aimed at halting the advance of the desert towards the north of the country by creating a barrier of vegetation linking the west and east borders of Algeria along a stretch of 1,500km. The project was entrusted to and carried out by young army conscripts.

The action plan for the relaunch project and rehabilitation of the green barricade to fight against desertification and climate change is in its final stage, said Saliha Fartas, director of the Direction Générale des Forêts (General Directorate of Forestry).

The planned objective is to extend the area of vegetation to 4.7 million hectares.

Involve locals

According to Nadia Brague Bouragba, research director at the Institut National de Recherche Forestière (National Institute of Forestry Research) station at Djelfa, 300km south of Algiers, it is important to involve local inhabitants in the project.

She said past mistakes with the green barricade were, first, the choice of species planted.

The Aleppo pine needs favourable conditions, such as the soil, for reforestation in semi-arid and arid areas.

Then there was the origin of the seeds, which had been harvested from all over the place when they should have been from the same region in which they were to be planted.

Also, there was the monoculture based on a single species, which later caused repeated damage from pine processionary caterpillars.

Lastly, local inhabitants had little interest in the Aleppo pine, regarding it as an invader of their pasture land.

Given its vast surface area, the green barricade must respond to non-negotiable priorities.

The first must be ecological: reforestation to protect the soil from erosion by water and wind; to mitigate the aridity and drought; to protect and enrich the biodiversity by organically increasing indigenous species; to relaunch a green economy by planting trees useful for those living on the plain, eradicating poverty and boosting agriculture at a low cost (with countryside fruit trees).

A positive socio-economic impact of the project needs to be perceived, by involving neighbouring inhabitants in it.

Alongside the government’s overall programme, researchers and university institutes have undertaken local initiatives to provide appropriate responses to the problem.

Cultivation of sisal

Two biology researchers have, for the first time, investigated the cultivation of sisal fibre, which is particularly suitable for stopping soil erosion in the country’s arid regions.

Experiments have already started in Naâma and Ghardaïa in southern Algeria.

“The sisal plant, originally from Mexico, needs watering three times when it is first planted, then it can last 11 years without being watered,” explained Abdelkader Fateh Bougherara, one of the project’s initiators.

Researcher Rachid Kada is the leader of the project in the west region, while Bougherara is the head of plantations in the east. The ministries of agriculture and the environment are involved.

These two researchers do not intend to stop there. Another project of 50ha has been launched in Ghardaïa with the aim of increasing the cultivation of sisal in the country.

In addition, a third sisal fibre experiment is planned in the Ouargla region.

Advantages and uses

While this plant perfectly resists a dry climate, was this the only reason the two biologists chose it? Bougherara described its different advantages and its many uses.

Among its environmental benefits is the sisal plant’s adaptability to the hot, dry climate. “This plant can contribute to strengthening Algeria’s green barricade,” Bougherara believes.

This renewable resource can respond positively to the problem of climate change. It is a biodegradable fibre.

Sisal reduces soil erosion, thanks to its deep roots, and contributes to good management of drainage basins. It also forms an efficient plant barrier to protect crops and forests from predators and intruders.

The very resistant fibre, which can be harvested four times a year, can be used for making ropes, carpets, matting and various handmade products. Its average yield in dry fibres is more than a ton per hectare.

According to the researchers, it can be used for a number of purposes. In agriculture, the plant’s juice, particles of crushed tissues and fragments of leaves and fibres can be used as fertiliser or cattle food.

For the automobile industry, the fibre can also be added to fibreglass to strengthen plastic in cars, boats, furniture, pipes and water tanks.

Grinding discs are also manufactured from the very strong sisal fibre.

It is worth noting that the textile sector is constantly searching for an organic fibre that can meet its users’ demands. The fibre of agave sisalana is also used in manufacturing textiles, and in the medical field, it can be used for the production of surgical alcohol.

Sisal fibre is also used for high-quality paper because of its qualities of absorption and resistance to creasing.

The researchers explain that the by-products of sisal can be used to manufacture biogas, pharmaceutical ingredients and construction material. The biomass remaining after defibration represents about 98% of the plant.