While the Sahara Desert is an important ecosystem in its own right, its human neighbors in the Sahel would like it to stop encroaching on their environment. [Andrew Millison] took a look at how the people in the region are using “half moons” and zai pits to fight desertification.
With assistance from the World Food Program, people in Niger and all throughout the Sahel have been working on restoring damaged landscapes using traditional techniques that capture water during the rainy season to restore the local aquifer. The water goes to plants which provide forage during the 9 drier months of the year.
The main trick is using pits and contouring of the soil to catch rain as it falls. Give the ground time to absorb the water instead of letting it run off. Not only does this restore the aquifers, it also reduces flooding during during the intense rain events in the area. With the water constrained, plants have time to develop, and a virtuous cycle of growth and water retention allows people to have a more pleasant microclimate as well as enhanced food security. In the last five years, 500,000 people in Niger no longer need long-term food assistance as a result of these resiliency projects.
If this seems familiar, we previously covered the Great Green Wall at a more macro level. While we’re restoring the environment with green infrastructure, can we plant a trillion trees?
I wonder if it will be independently managed long-term
sshhhh, don’t you ask critical questions about the longterm sustainability of development aid projects.
Whether or not these half moons are planted with productive species or not, the operation is a function of physics. Water flows to the lowest point in the landscape, and these half moons represent such low point. They fill up and then overflow in monsoon rains, creating a microclimate of moisture, organic matter and moderated temperatures.
All of these things benefit tree growth and they will continue to function as such regardless of human inputs. Only a bulldozer could flatten these out again.
Serious projects, and the ones supported by the WFP are certainly among them, focus on building a foundation of local stakeholdership. That’s why plant species are included that produce animal fodder (grasses in the immediate aftermath of rains, but also trees like leucaena that extend the animal feed production into the dry season, cassava etc.).
It’s a lot less about preserving the status of a system once set up than it is about re-familiarizing locals with restorative farming and land management principles that bring about continued improvements as the systems mature.
[The Food Forest Namibia] is another example for that. At 3 min 30 s (link below), he’s driving down the road comparing the flat, continuously grazed neighbor land to his where water harvesting features have been added, and cattle is being kept away until the grass has been given the chance to grow to a reasonable size.
He’s been applying permaculture principles for a while now, and people are starting to be curious as they see the results manifest.
https://www.youtube.com/watch?v=9pmDBYAMPIM&t=3m33s
Animals need to be in the system managed carefully see savory institute and many other regenerative farming practices in semi arid lands
Their is very little rainfall in the Sahel. Is it enough for the tree in each half moon to grow or does it still require periodic watering until the tree roots develop more?
Several factors come together. There is a succession from annual and perennial weeds and grasses to a system that can support shrubs and trees. As dirt is gradually turned back into soil, it can infiltrate and hold onto water better in the root zone.
Where there is flooding, there is also likely a moderately sloped region that gets fed by both direct rain collection and surface runoff.
After a couple of years, conditions support tree growth, and it’s not uncommon to see volunteer species pop up as well.
The Al Baydha project is an even more extreme example, and there they chose to let nature work out which of the planted and initially watered species would survive.
After over 2 years of no rain, and without watering, it became clear that the ecological potential was limited to a grassland savanna with few or no trees.
Against that, the 15% of precipitation retained and replenishing the aquifer at the Niger site suggests to me that as long as grazing is controlled, trees won’t struggle to get established without extra watering.
When it does rain in the Sahel, it rains in a big amount at once. Monsoon rains often cause flood events but these half moons act like speedbumps and bathtubs at the same time, intercepting the rain. It is designed to function without additional watering.
“While we’re restoring the environment with green infrastructure, can we plant a trillion trees?”
Course we can have someone wandering the wasteland, calling themselves, the soil survivor.
How can I best help this important work?
I have taken a Permaculture Design Course in 2010. I am currently a permaculture designer and teacher for my profession, just like Andrew Millison who made this video. I make these kinds of designs for people’s homes and gardens. It is truly some of the most satisfying jobs I could ever imagine because it impacts the future generations in a positive way!
I’m sure there are a number of organizations that execute these programs and need more funding. The one I donate to is called Just Diggit. Their web site is very educational. They have a couple approaches not mentioned here involving things like harvesting/selling seed and pruning existing tree for much better growth. All of it is community based.
Watching this video, I couldn’t help but think about what Frank Herbert wrote in Dune, of how the fremen reclaimed Arrakis from the desert using processes very similar to everything described here.
I think its kind of cool to see geoengineering applied at large scale like this using relatively low tech methods.
With all that wind they could build windmills too.