Senegal's circular gardens hold back the Sahara

These Senegalese farmers are planting spiralling gardens of edible and medicinal plants.

(Aly Ndiaye, agricultural engineer) "So you see here it's almost 100 papaya trees, here you have the medicinal plants in the front row the next three rows are dedicated to the vegetables, a variety of vegetables, the papaya, the lemon trees, citrus trees, cashew trees, the natives (trees), fertility trees, and at the back the Baobabs and the African mahogany which are bigger, so in the end we have an island just here."

The garden is part of Africa's Great Green Wall project.

It's an ambitious attempt to slow down the encroaching sand of the Sahara desert

by planting a 5,000-mile belt of trees across the length of the Sahel - from Senegal to Djibouti.

We're in Boki Diawe, a border town of northeastern Senegal.

Local residents are planting these circular, drought-resistant gardens known as 'Tolou Keur.'

Their purpose is multifold: reforestation, slowing desertification, and improving food security and livelihoods of the people living in the Sahel.

Agricultural engineer Aly Ndiaye designed the Tolou Keur.

"You need to think of the Great Green Wall as big, but with actions that are permanent, useful and sequential. Not "we should make the Great Wall greener," but you see, and it's possible. (Imagine) 1,000 Tolou Keur, 2,000 Tolou Keur interconnected? 1,000 Tolou Keur equal 1.5 million trees, do you realize? So if we start we can make a lot."

The African Union and international partners launched the Great Green Wall in 2007.

But the project has since stalled.

14 years in, only 4% of the pledged 247 million acres of trees have been planted. That's according to the United Nations' estimates.

The scheme has also been criticized for its narrow focus on reforestation,

neglecting other approaches that could better curb the economic impact desertification has had on local residents.

In response, some organizers are shifting to different approaches – such as the Tolou Keur gardens.

Ndiaye says the key to the success of the Tolou Keur gardens has been a strong sense of local ownership.

This is Moussa Kamara.

He works at a local bakery at night, but when the sun rises he heads to work in the garden.

"The day people will realise the full potential of the Great Green Wall, they will stop these dangerous migrations routes where you can lose your life at sea. I think its much better work the soil for two years, two years only. With what they will harvest, here, they will never want to leave because they will have their fathers, their mothers, their wives and their children with them. It's better to stay, work the soil, cultivate and see what you can earn."

It's not clear how successful the new projects will be.

At one Tolou Keur in the remote village of Walalde, the desert had already begun to reclaim the land.

But most Tolou Keurs have flourished.

In the seven months since the project began, around two dozen of them have sprouted throughout Senegal, according to the country's reforestation agency.

Karine Fakhoury, who is the director of the eco village and green sector at the Reforestation Agency, came up with the idea of planting the circular gardens.

"This circular notion is strong, because there is biodiversity, meaning that there a number of species that are mixed. It allows you to reinforce the production without using chemicals, therefore it is the strength coming from the mix of species that allows the set up of permaculture."

The design of the garden is also important.

Circular beds allow roots to grow inwards, trapping liquids and bacteria and improving water retention and composting.

Senegalese-born Ndiaye, who is based in Brazil, worked with Fakhoury on the garden's design while he was stuck in Senegal

after the borders closed due to the global health crisis.

"I feel good, I've done a lot in Brazil, but I feel better being at home. And I think that this is probably making the diaspora think as well, the building or our dear Africa, it has to be done by people who are here but also by the diaspora, because we have a lot of knowledge, we have to come back and build. // What I'm doing here excites me, I feel more useful, because there people can probably continue my work better than me, here we need it, we need us, we have to say it, I'm ready for this, I don't care about the rest."