These photos show the digging of banquettes at the edge of town. Banquettes serve the same function as demi-lunes: to make the hardpan soils usable. Last photo is a demi-lune.
As you can imagine, Niger's climate, topography, and heavy land-use (grazing) provide a perfect situation for the formation of hardpan, and there are miles upon miles of it throughout the country. One method of land reclamation--i.e. turning unproductive land into something greener-- is the building of demi-lunes: the digging out of large, 5-meter long, 1-foot deep crescent shaped holes in the hardpan's hard shell. A sapling- usually Gum Arabic- then gets planted in the space. Typically, hundreds to thousands of demi-lunes are dug at a time, in the interest of improving large swaths of land. The crescents are aligned to catch rainwater that would otherwise race off, giving it a place to soak in and hang out for awhile. In time, seeds of grasses and shrubs also get caught in the crescents, take root, and spread. The effect is impressive; you can look out on acres upon acres of the demi-lunes and see bright green, lush crescents standing out against the otherwise rusty beige color of hardpacked earth.
We have over 9,000 demi-lunes in my immediate area; all of them were dug in the last 3 years by the men, women, and kids of my village and a couple of surrounding villages. It's back-breaking work- imagine chopping at a parking lot for a few hours in the sun. Blah. When I arrived last year, people were in the midst of a big demi-lune project, and I joined in to dig three big pits of my own. Each one took me about 2 hours, I think, and I had to wait a week between each of them for my patheticallly soft, blistered hands to heal enough for me to go back. The project was paid for by an Italian NGO, COSPE, which paid 250CFA per demi-lune (about 50 cents).