Zaï Pits — Farmer-Led Water-Harvesting Restoration of Degraded Cropland, Yatenga, Burkina Faso

Zaï are traditional planting pits, roughly 20–30 cm wide and deep, dug into crusted, degraded cropland before the rains and filled with manure or compost so that scarce rainfall and nutrients concentrate exactly where a millet or sorghum seed is planted. Farmer Yacouba Sawadogo, from Gourga near Ouahigouya in Burkina Faso's Yatenga province, revived and refined the technique from 1980 onward after severe Sahelian droughts.

Sawadogo added organic matter to the ancestral pits and, from 1984, organised annual 'zaï markets' that drew farmers from over a hundred villages to exchange seeds and know-how, spreading the practice through the farmer-led Association pour la Promotion des Zaï.

Agronomists from CIRAD, INERA and ISRA report that zaï-treated plots in the Sahel can yield around 1,500 kg of millet or sorghum per hectare, compared with under 500 kg/ha on untreated, crusted soil, though other academic reviews of zaï across the wider Sahel report a broader range of roughly 50–200% yield uplift depending on site and season. On his own land, Sawadogo used the method to convert about 27 hectares of barren ground into forest now hosting more than 60 tree and bush species.

The practice is labour-intensive — about 380 hours per hectare by hand, reduced to roughly 50 hours with animal-drawn tine adaptations — and requires around three tonnes of manure per hectare, which independent reviews flag as the main barriers to wider adoption. Sawadogo's work was recognised internationally as UNCCD Global Dryland Champion (2013) and UNEP Champion of the Earth (2020) before his death in December 2023.