Sustainable in Senegal
From dunghills to compost pits and back again – only better

How Senegalese farmers learned, practiced then radically adapted composting to fit their land, culture and settings.

By Nathan C. McClintock
September 1, 2005

Sustainable in Senegal

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A rich slice of sustainability in Senegal:
The Rodale Institute® showed this American agriculture student the critical need for soil innovative soil saving practices in West Africa.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

West Africa calls you back

West Africa gets deep into your marrow, haunts you, calls you back.

After two years there in Peace Corps working with farmers in Mali, I was yearning to return to the region. In 2003, that call drew me to Senegal where I spent a semester as an intern at The Rodale Institute to compliment my graduate research in sustainable agriculture. I wanted to see how TRI was able to transfer its expertise to farmers, helping to improve their livelihoods.

The Senegalese farmers I met were eager to share their stories, their food, and their laughter. Their resilience and creativity farming on the edge of the Sahara can serve as inspiration to us all. – Nathan C. McClintock

It might seem crass to suggest that the world’s greatest civilizations have been built on foundations of their own waste. Perhaps. But civilizations as we define them grew as a function of agricultural productivity. And since humans first began scraping the ground and planting seeds some 15 millennia ago, they have relied on decomposed organic matter—manure, garbage, crop residues—to replenish the soil’s fertility.

Sir Albert Howard, a British agronomist working on colonial plantations in India in the 1920s, grew frustrated with the growing incidence of plant disease and loss of humus in Western monocultures. He noted, “The Chinese have maintained soil fertility on small holdings for forty centuries.” At the same time he recognized the inefficiency of the traditional method of stacking manure in piles. In his 1943 memoir An Agricultural Testament, Sir Albert, in his zealous, surly prose declared, “The fungi and bacteria of the manure heap are working under impossible conditions. They live a life of constant frustration which can only be avoided by giving them a balanced ration.”

English writer spreads compost gospel


While composting is only a tiny part of the Rodale Institute's program, it's an important one. Here, Rodale technician Oury Diallo examines the compost pits in the Keur Sa Daro women's garden.

After experimenting with different methods of composting, he brought the injustices of the dunghill to the world’s attention in a 1931 publication detailing the so-called “Indore method,” named for the state in India where he and his colleagues conducted their research. The Indore method is what we all know as composting—piles or pits of manure or organic waste layered with dry matter to facilitate aeration, watered regularly, and turned every month or so. Following his clarion call, the Indore method spread to British tea and coffee plantations throughout Africa, Asia and the Caribbean. It is the first thing all Peace Corps ag volunteers learn to do. And it’s central to the Rodale Institute’s (RI) extension work to promote regenerative agriculture in Senegal.

While composting is only a tiny part of Rodale’s program to increase organic matter content in the sandy jóór soils of the Peanut Basin, it is an integral one. Since the Senegal office opened in 1987, tens of thousands of farmers and extension workers have been trained in regenerative agriculture techniques, a large portion of whom received instruction in Sir Albert’s trusted method of pit composting. Trainings are conducted with the expectation that the participants themselves will go on to perpetuate the technology on their own as its benefits become apparent. For example, following RI’s work with the Projet de Gestion des Eaux de Casamance (PROGES), farmers set up 800 composting pits based on the ten constructed for training demonstrations. Rodale has also published pamphlets and booklets in both French and Wolof detailing the technique.

Results from Rodale’s on-farm experimentation with compost have been impressive. The 1990 annual report provides the results of on-farm composting trials at N’Gombel and Mboufta. Millet grain yields (1270 kg/ha) in plots fertilized with compost were four and a half times greater than unfertilized controls (230 kg/ha). In peanuts, the increases were not so pronounced, but still favorable. Plots fertilized with compost yielded 230 kg/ha more peanuts than plots fertilized with manure, and one metric ton per hectare more stover, or ngooñ, a valuable fodder for livestock.

At Mboufta, in the Departement de Tivaouane, north of Thiès, an application of two tons of compost every two years has yielded 3.5 times the millet than control plots, and 125 percent of the local farmers practice of varying rates of manure application. Promising results pointing to compost’s superiority mark all of Rodale’s work in Senegal throughout the last fifteen years or so, and were Sir Albert still around, he’d certainly revel proudly in his triumph.

Why the better results from compost over manure? Is there actually a difference between compost and manure that’s been sitting in a pile? It’s a fine line that farmers and extension workers run circles around. Basically, it depends on whether or not the pile has heated up.

Results from Rodale’s on-farm experimentation with compost have been impressive. Millet grain yields in plots fertilized with compost were four and a half times greater than unfertilized controls.
Without getting too technical, life in a dunghill proceeds as such. Microbial populations in the waste consume the readily available carbon. As they metabolize it, CO2 is released, heating the pile up. This heralds a whole new slew of thermophilic, or heat-loving bacteria that consume the rest of the degradable carbon. As activity slows down, the pile temperature drops, allowing for colonization by fungi that consume much of the remaining recalcitrant forms of carbon—lignins and cellulose. The resulting crumbly, earthy humus is considerably more stable than manure, meaning its nutrients are less likely to be lost to leaching or volatilization into the atmosphere.

As compost matures, its nitrogen is mineralized, meaning it moves from its organic form to ammonium and then nitrate, the form that can be taken up by plants. If a pile of wet manure just sits there unturned, it will likely become anaerobic and smelly as precious nitrogen is lost as ammonia gas. Sir Albert’s mission was to optimize the conditions for decomposition. This could be seen as a gesture of magnanimity to keep the microbial workers happy and productive, in a manner or speaking.

Great intentions, but…

RI has been wracked with the same frustration in the past as so many other NGOs and development workers. Oftentimes, once a project has finished, participants will abandon their composting pits and go back to traditional methods of manure application. In his 1982 classic Two Ears of Corn, the how-to Bible of participatory development, Roland Bunch writes, “The rusting hulks of well-intentioned but long-forgotten give-aways are scattered all over the Third World.” I’ve seen quite a few empty compost pits during my first month in Senegal. When I ask farmers why they stopped composting, they generally tell me that it takes too much water, that they don’t have enough manure to fill the pits, or that turning the compost is too labor-intensive.

The Rodale staff is well-aware of the problem of “dis-adoption”. Earlier this year, they conducted a follow-up impact survey of a project carried out between 1996 and 1999 in the Tambacounda region, the southern reaches of the Peanut Basin. A partnership between RI and the Association Communautaire pour le Développement de Koumpentoum (ACDK), the three-year, $161,000 project funded by USAID promoted regenerative techniques and local economic capacity-building in the rainfed agriculture zone (“zone pluviale”).

Four years later, they found that while 75 percent of the Arrondissement de Koumpentoum practiced at least one of the techniques promoted by RI, the adoption rate of compost was much lower. Farmers complained of the same things that they’ve been telling me. Digging the pits was too labor-intensive. Inadequate supplies of manure. The high cost and limited availability of cement. Adapting to these constraints, farmers in Darou Salam Thièkène switched over to pile composting. Compost piles, while slower to decompose, require little labor and are often watered only by the rain.

More recently, during the first year of the Vanderbilt project, six sacks of cement were given to each of the five villages for the construction of two 2m3 pits. In 2001, the first year of the project, four composting sessions were held, with 60 attendees (49 of them women). Over the course of the gardening season, the villages produced 8,800 metric tons of compost in the pits. However, outside of the communal plots, only 13 percent of the participants used compost as a soil amendment, while 52 percent used manure.

Adapting to farmer constraints

Learning from their previous experiences, Rodale emphasized pile composting during the 2002 sessions in an effort to increase compost adoption. The results have been as sweet as the smell of the compost itself. In Keur Banda and neighboring Diouffène, compost production among group members is universal. All of it is produced in piles. As I was led from compound to compound, I saw enormous piles of decomposing manure, stalks, household garbage, alongside smaller piles of humic, “ripe” compost, kompos bu nuur.

One Keur Banda farmer, Amy Diop, complained to me that she has so much compost that she can’t get it out to her field without a cart. In Thiawène I asked, “Who makes compost in this group?” “Ñun ñëpp! All of us!” they replied heartily.

Next door in Ndiamsil, a farmer stood next to the gaping, empty pit that had been the site of so much activity a decade ago. “No, we stopped making compost,” he shook his head slowly with resignation. Yet not 10 feet away was a huge pile of composted manure and millet residue! Indeed, it is often simply a question of blurred definitions. In most rural compounds, manure, household garbage, cooking ashes, and broken or decomposed millet stalks from fences are stacked in a pile, a sentaare. Some people just leave this throughout the duration of the rainy season to decompose on its own, while others turn it every month or so. When I asked if it smelled or was hot when they disturbed the pile, most said that it had cooled off and turned back into suuf—soil—by the time they scattered it on their fields. It might not be produced under the optimal conditions, but it’s compost nonetheless.

The key to successful development is to build on what people already know. The movement from compost pits to piles is a classic example of local adaptation of a technology to better meet labor and material constraints. Pile composting is also more closely akin to a traditional practice. In Thiawène, the women recognized the superiority of their pile compost over the family sentaare compost—millet fertilized with the former was a darker shade of green. But they each only had produced two to three cartloads of it, as opposed to 10 to 12 cartloads from the sentaare. With a just a little more attention—by turning it more often—the sentaare could produce compost as rich as that produced in the piles.

Championing manurial rights


"Can anything be done at this late hour by way of reform? Can Mother Nature secure even a partial restitution of her manurial rights?”
Can anything be done at this late hour by way of reform? Can Mother Nature secure even a partial restitution of her manurial rights?” Sir Albert’s pleas, while a wee melodramatic, are pertinent to the case of Senegal’s Peanut Basin nevertheless. As fallows get shorter and disappear altogether, the sandy soils are in dire need of organic matter if they are to continue to be productive.

When I asked farmers in Thiawène if the soil had become less fertile in the last five years, they surprised me with their response. “Déédéét, léégi suuf si moo gënë naat. No, now the soil is more fertile.” They explained that with the increased application of organic matter over the last few years as prescribed by Rodale’s workers in the field, less of the precious topsoil is lost to the wind and rain, and yields are getting better.

Sir Albert was right: “If the easiest road is first taken, a great deal can be accomplished in a few years.” So turn those dunghills and keep those carts rolling!

Nathan McClintock made a lot of compost as a Peace Corps ag volunteer in Mali. He holds an M.S. in sustainable agriculture from North Carolina State University. He just returned from assisting a farmers’ group Nepal in its transition to organic. He will be starting a PhD in agroecological geography at Berkeley this fall.