Astrophysicist Hubert Reeves once said, “On a cosmic scale, liquid water is rarer than gold.” This statement rings even truer in the Sahel, a vast arid region stretching from east to west along the Sahara’s edge in Africa.
Here, water is the most precious commodity. Since 3000 BC, the people of the Sahel have gone to great lengths, using their creativity to harness and manage this scarce resource. They’ve had to develop smart, frugal techniques to make the most of every drop, given the uneven distribution of water both spatially and temporally.
Recently, the ingenuity of Sahelian farmers has caught the eye of scientists and policymakers alike. Their time-tested methods are now serving as a blueprint for adapting to climate change in African agriculture and potentially influencing practices worldwide.
Rainfall in Yatenga: A Seasonal Lifeline
Each June, the first showers in Yatenga, northern Burkina Faso, offer a welcome respite from the relentless dry season. This rain breathes life into the parched earth, sparking bursts of millet and sorghum that transform the barren savannahs into lush green fields.
However, not all areas rebound so vibrantly. Decades of severe droughts during the 1970s and 80s devastated the fragile Sahelian ecosystem of Yatenga. The sparse vegetation led to severe soil erosion, leaving the land barren and compacted. When the rains do come, they mostly just wash over the surface, carrying away not just the soil but the farmers’ hopes as well.
Amidst this stark backdrop, some resilient farmers are pioneering new methods. Yacouba Sawadogo is a standout example. In the arid village of Gourga, he and his family prepare their fields before the rainy season hits.
Using traditional tools, they puncture the tough laterite soil, meticulously filling these holes with a mix of compost and sorghum seeds, topped with a thin layer of soil. This preparation might seem unusual, but it’s a revival of an ancient local technique known as zai—proven to capture and utilize scant rainfall efficiently.
This method, forgotten since the 1950s due to ample rainfall, became crucial again in the arid 1970s and 1980s as desertification advanced. Yacouba Sawadogo, now famously known as “the man who stopped the desert,” chose to stay and fight the encroaching desert by reviving zaï.
His efforts have rejuvenated 27 hectares of degraded land, earning him the title “Champion of the Earth” from the United Nations and making him a symbol of innovation against desertification in Africa.
The Rising Need for Sustainable Agriculture in Developing Countries
By 2050, the world’s population is set to exceed 9 billion, which will push global food demand up by 70% compared to 2005 levels. This surge is predominantly expected in developing countries, including Ghana.
As agricultural land becomes increasingly scarce, adopting sustainable farming technologies is essential for boosting food production and tackling environmental issues.
Conservation agriculture (CA) is a method that has been effectively used to enhance soil health, conserve water, and increase farm productivity.
Originally developed for large-scale farms in the United States, CA has since been adopted widely in developing countries, particularly in Sub-Saharan Africa, through the support of international agencies. This approach focuses on minimizing tillage, rotating crops, and maintaining organic soil cover to protect and enrich the soil.
In Burkina-Faso during the early 1960s, local farmers invented the Zai technology, a traditional form of conservation agriculture that involves creating small pits filled with organic matter to improve soil fertility and water retention.
This method has proven especially beneficial during droughts, helping to stabilize yields and reduce emigration by rejuvenating arid lands.
However, despite its effectiveness, the uptake of Zai technology in places like Ghana’s Garu-Tempane district remains low. Factors like limited information, institutional barriers, and varying local conditions complicate the adoption of such innovative practices.
To better design and implement farming programs that encourage the use of sustainable technologies, it’s crucial to understand both the decision to adopt and the extent of use. This understanding can guide policies that support farmers in making the most of practices like Zai, ultimately enhancing food security and sustainable development in the region.
Enhancing Soil Fertility: The Role of Zai Technology
Zai technology is a traditional method for boosting soil fertility and water conservation, involving the burying of organic matter in small pits. Despite its environmental benefits, it’s not widely used. This study highlights two main findings.
Firstly, it explores the factors that influence farmers’ decisions to adopt Zai technology and how intensely they use it. Secondly, it evaluates different statistical methods, concluding that the Cragg’s double-hurdle model is the most effective for understanding these factors in Ghana’s Upper East region.
This approach showed that various factors impact the likelihood and level of using Zai technology. The research suggests that encouraging farm households to pursue additional non-farm income can help them afford more farm inputs.
Also, policies that increase access to agricultural services, credit, and support farmer groups are crucial for broader adoption of innovations like Zai technology.
How Zai Pits Work: A Traditional Agricultural Method
In the early 1960s, farmers in northern Burkina Faso developed a clever method called “Zai” to rejuvenate their parched, degraded land. This technique involves digging small pits, roughly 20-30 cm wide and 10-20 cm deep, spaced about 60-80 cm apart.
These pits are strategically used to conserve soil moisture and improve crop resilience during droughts, a common challenge along the southern fringes of the Sahara. Various regions, including the Tahoua area in Niger, have adopted this method under different names like “tassa.” In English, it’s often referred to as “planting pockets” or “micro pits.”
This farming innovation spread to countries across Africa to boost agricultural productivity and support food security. For instance, in 2010, the Garu Presbyterian Agricultural Station in Ghana introduced Zai pits to local farmers, enhancing their ability to thrive in areas with minimal rainfall, which ranges between 300-800 mm annually.
This introduction was crucial, given the Sahel savanna’s harsh conditions and its impact on local farming communities. Over the years, Zai pits have shown to significantly boost land productivity, enhance soil fertility, and increase farm yields by up to 500% if properly managed.
Despite its success, the economic benefits of Zai technology on the welfare of farm households in Ghana have been underdocumented. Thorough research could help
spread this effective agricultural technique further, improving the lives of many farmers. The Zai method not only helps in managing drought conditions but also plays a critical role in combating soil erosion and creating a nurturing micro-environment for crops.
Unlocking the Secrets of Zaï Farming: More Than Just Holes
You might think it’s just a simple hole, but there’s a lot more to zaï than meets the eye. This clever farming technique harnesses a series of complex ecological interactions to boost crop growth under challenging arid conditions.
Here’s how it works: during the dry season, farmers dig small holes—about 10 to 15 cm deep and 20 to 40 cm wide. These are then filled with organic fertilizer and planted with cereals like millet or sorghum.
When the elusive rains finally arrive, these prepared holes, enriched with nutrients, fill with water. This attracts termites, specifically from the Trinervitermes genus, which play a crucial role. As these termites burrow, they enhance water infiltration and break down the organic material in their path, making it more accessible for the plants.
This not only moisturizes the soil but also creates a fertile spot where plants can robustly grow their roots. Some studies have shown that with zaï, crop yields can surge to 1500 kg per hectare, a significant jump from the usual 500 kg per hectare.
But zaï doesn’t just improve crop yields; it also encourages biodiversity. The holes capture seeds from various tree species, carried by wind, water runoff, or even animal droppings. This leads to the spontaneous growth of shrubs and trees, enriching the ecosystem.
In the Yatenga region, for example, farmers nurture these young trees, which become vital sources of fertility and fodder during dry spells. Over in Senegal, researchers are exploring how much carbon these zaï plots can store, with early findings suggesting a 52% increase in carbon storage compared to non-zaï fields.
Despite its benefits, zaï is labor-intensive. It demands a lot of manual work—around 4 hours a day with a simple tool like a daba to prepare one hectare over three months. Plus, each hectare requires about three tons of manure.
The term “zaï” itself comes from the Mooré word “zaïégré,” meaning “to get up early and hurry to prepare your land”—a nod to the effort involved. Yet, for many, the promise of better harvests and environmental benefits makes it all worthwhile.
The Spread of Zaï Farming Across the Sahel
Zaï farming, a clever technique rediscovered in Burkina Faso, quickly caught on across Mali, Senegal, Niger, and Kenya. Back in the 1980s, efforts to fight desertification ramped up due to severe droughts in the Sahel. By 1982, agronomists from CIRAD were in Burkina Faso’s Yatenga region, touting zaï as a promising method to rejuvenate the land.
This sparked numerous initiatives across sub-Saharan Africa to explore and refine zaï. In Burkina Faso, organizations like INERA and Solibam began mechanizing the digging of zaï pits to reduce labor.
Instead of manual digging, they used a tine attached to an animal to create intersecting furrows where seeds were planted, slashing the work time from 380 to 50 hours per hectare. In Senegal’s Ndiob, Mayor Oumar Ba took it up a notch by giving out mechanical augers to farmers, which simplified and sped up pit creation.
INERA didn’t stop there; under the Fair Sahel project, they are conducting trials to substitute some organic manure in zaï pits with mineral fertilizers to boost sorghum production and reduce costs.
They’re also experimenting with planting sorghum alongside legumes like cowpea and trying zaï with new crops like corn, cotton, watermelon, and vegetables like eggplant.
In Senegal’s market gardening areas, zaï’s adaptability has led to various modifications. In Fatick, farmers use recycled tires to direct manure and water straight to the roots of pepper plants.
In Mboro, onion beds are transformed into mini basins for efficient watering, and in Kolda, eggplants are nestled into straw-covered pits. These innovations share a common goal: to maximize water and nutrient use in a challenging climate.
The Global Race for Agricultural Water: Challenges and Risks
As the climate crisis deepens, countries worldwide are racing to boost their water supplies for farming. This has led to a surge in the construction of dams, mega-basins, and vast irrigation networks, all aimed at expanding irrigated farmland by any means necessary.
However, while these efforts may solve immediate water needs, they introduce a troubling set of challenges. Overuse of water resources, social disparities, and international disputes often shadow these large-scale hydro-agricultural ventures. This growing agricultural framework appears precarious, heavily reliant on water sourced through energy-intensive methods.
In a bold departure from this trend, Sahelian farmers have embraced a more sustainable approach. These resilient “barefoot researchers,” accustomed to centuries of water scarcity, have been quietly pioneering innovative solutions. Eschewing the mantra of “more water at any cost,” they’ve adopted a philosophy of minimalism.
Techniques like zaï—though widely recognized—are just part of their broader toolkit, which includes half-moons, stone lines, fruit bowls, and ponds, all employing traditional knowledge that could greatly benefit areas facing similar climatic challenges expected in the Mediterranean by 2100 under a +4°C warming scenario.
To reshape our global perspective on water’s future, we should turn our attention to the wisdom of Sahelian farmers and explore their low-tech, high-impact strategies for sustainable water use.
