Conversation with Dr. Cheikh Mbow

As Executive Director of the non-profit START, Dr. Cheikh Mbow works to strengthen the capacities of developing nations to advance sustainability through scientific research and education. Born and raised in Senegal, Dr. Mbow holds a Master’s degree in physical geography and a PhD in remote sensing focused on savanna conservation. Dr. Mbow has contributed research on ecological modeling, risk, and sustainability to the Intergovernmental Panel on Climate Change and the World Agroforestry Center. bioGraphic  recently spoke with him about how to transform the future of food production in Africa without compromising the ecological resiliency of the continent.

Q: Across Africa, hunger currently affects 25 percent of the population. What are the most significant issues contributing to this problem?

A: There are four main factors driving hunger and food insecurity in Africa. The first is land degradation. Before colonial times, a traditional landscape approach to farming in Africa considered trees, crops, and animals all together. After colonial times, monoculture approaches—raising one crop across a landscape—became the dominant farming practice, and soil quality was destroyed as a result. The second factor is climate and weather patterns. Alternating periods of flooding and drought, both of which have become more frequent and intense with climate change, have made it very difficult to ensure stable food production. The third factor is market forces, which set higher prices for cash crops like cacao and coffee and provide few economic incentives for African farmers to grow staple foods. The fourth factor is pre-consumer food waste. Large amounts of food are wasted in the supply chain before the final product even reaches the consumer. The Food and Agriculture Organization of the United Nations predicts that solving the food waste problem would resolve the deficit of food production in Africa entirely.

Q: How is climate change projected to impact Africa’s food production?

A: We have already seen dramatic changes in seasonal rainfall patterns and extreme water events. Over the past 30 years, the onset of the rainy season has been delayed, leading to variable productivity at the end of the dry season. Dry spells have also become more frequent, sometimes even occurring when rain is expected most, at the peak of the rainy season. In addition, extreme precipitation events, and the floods and crop destruction they often cause, have become more common. All of these factors have made crop productivity less and less predictable across Africa.

In the long-term, the Intergovernmental Panel on Climate Change (IPCC) has projected large, geographic changes in rainfall patterns. Unfortunately, the rate of long-term climate change is far outpacing the ability of crops to adapt. To ensure that food production doesn’t collapse, we will have to introduce different varieties of plants that are better suited to future climate conditions—which in many cases will mean crops that require less water.

Q: Many efforts to increase agricultural yields have encouraged focusing on a single crop, and utilizing synthetic fertilizers and pesticides. What are the risks of this approach?

A: Mono-cropping, or focusing on a single crop, has inherent financial risks because of external market forces that can change without notice. It’s also ecologically risky. When you raise just one crop, each plant is competing for the same resources: They all have the exact same demands for water and nutrients. Monocrops are also more susceptible to pests and plant diseases, due to the ease with which these threats can spread through fields of a single crop. Synthetic fertilizers also come with risks—and applying massive amounts of synthetic fertilizers, especially when that’s the only strategy employed, is simply not effective. Without organic matter like compost and leaves, fertilizers won’t be retained in the soil.

Now imagine a landscape with grasses, trees, and some deep-rooted shrubs: These plants have varying root depths and varying demands for water. They coexist more harmoniously on the land, doing such things as enabling pollinators to move more readily from one species of plant to another. We need a more holistic approach like this to achieve ecological resiliency across the African landscapes.

Q: What aspects of this “monoculture” approach are particularly challenging for small-scale farmers?

A: Cacao, coffee, and several of the other major cash crops that Africa’s farmers end up producing on a massive scale don’t help them feed their families. What these families really need is food, firewood, farm animals, and more nutritional variety in their diet. By forcing farmers into mono-cropping practices, we are compromising their ability to sustainably support their own existence through a variety of land uses and ecosystem services.

We also need to ensure that the farmers who rely on a few hectares of farmland don’t bankrupt themselves by depending exclusively on synthetic fertilizers. Typically, fertilizers like nitrogen, phosphorus, and potassium are combined into one product that is sprayed openly onto fields. The industry supplies these fertilizer products, knowing well that much of what they contain is unnecessary. And they provide no instructions for how to target specific crops with certain fertilizers. This blanket approach does nothing to address specific mineral deficits or to provide optimization for soil fertility. We’ve also found that soils without a minimum amount of organic matter produce less than expected even under intense applications of synthetic fertilizers.

Q: You advocate for maintaining biodiversity. Why is this an important component of a sustainable agriculture plan?

A: Biodiversity in and around agricultural land provides a number of ecosystem services that support higher crop yields. Imagine a plot of land surrounded by trees. It’s likely that the trees protect that land from erosion by wind and water. The shade they provide also ensures that crops don’t dry out as quickly.

Many farmers also know that trees are natural pumps for fertilizers. They take nutrients deep from within the soil, convert it to biomass in the form of leaves, and when those leaves fall to the ground they decompose into natural fertilizers for the soil. The higher the diversity of these fallen leaves, the better the soil quality. The trees can also fix nitrogen into the soil for various crops to use. Trees have root systems that reach to different depths than those of crops, so the more diverse a plot of land, the more balanced the share of resources. This leads to greater ecological balance and higher crop yields.

In addition to boosting crop yields, biodiversity and balanced ecosystems also support the health and wellbeing of small-scale farmers in many other ways, including delivering clean water, mitigating disease, and providing fuel, fiber, and building materials.

Q: You have discussed the importance of biodiversity in providing access to fresh water, a resource in increasingly short supply. How should these services be factored in to sustainable agriculture and development plans?

A: Access to clean water is a growing concern in Africa, particularly in urban centers, since not all sewage is processed. Substances including nitrogen and heavy metals reach the water table, and in many growing urban centers well water is now unusable due to risk of contamination. Restoring wetlands and mangroves—and ensuring that dam construction doesn’t cause downstream wetlands to dry up—can help buffer these contamination effects. For example, wetlands can help filter the harmful fertilizers that run off from agricultural fields and into nearby rivers.

Protecting and restoring wetlands, an ecosystem that is being destroyed at an unprecedented rate in Africa, would help keep our fresh water clean.

Q: What are some of the most effective approaches to rehabilitating degraded agricultural land?

A: There is no easy answer to this question, as the approach depends largely on the preferences of the local communities, the type of soil, the topography, and the region’s climate patterns. Essentially, creating a multifunctioning landscape instead of a mono-functioning landscape is key. The recommendation is to design approaches to land management and agroforestry practices that increase soil fertility in a variety of ways.

Q: Which sustainable agriculture practices have you found to be most effective in Africa?

A: One agricultural practice I’ve seen work well is managing the natural regeneration of land in my home country of Senegal. Farmers there are bringing back trees—including a deciduous tree, Faidherbia albida—to rehabilitate the land, and many of these tree species fix nitrogen in the soil. When their leaves drop, they introduce organic fertilizers into the soil just when the crops need fertilization most. We’ve seen farmers use these traditional methods, and the results have improved food quality and a balance between food production and cash crop production without departing from tradition and land health.

I’m not saying we should never use synthetic fertilizers, but we should avoid relying too heavily on them. We must work to strike a balance between traditional and modern applications.

Q: What are the main impediments to implementing these context-dependent systems?

A: We need a cultural shift to happen in three phases. First, we need to establish a dialogue with decision-makers and stakeholders involved in food, water, and energy to define common goals and begin a solutions-based dialogue. Second, we need to ensure that we understand the systems of food, energy, and water appropriately by examining their interconnectivity. Last, we have to use this knowledge to disseminate a wider solution to the community at scale. Combining food, energy, and water policies under one department at a national or federal government level would be a great start.