Could an indigenous shrub lessen food shortages in West Africa?

07 Nov 2018 --- Guiera Senegalensis, a resilient shrub that grows in West Africa, could be key to solving the region’s food shortage, due to its unique ability to find and distribute water in drought conditions. Researchers in Senegal have found that the shrub that grows in the area, could help with declining crops due to drought.

The Guiera shrub has the ability to draw water from underground sources up to 40 feet deep. Then at night when it is not photosynthesizing, it releases the water close to the surface. The neighboring plants, in turn, absorb the moisture, allowing them to flourish.

Published in the journal Frontiers in Environmental Science, the study found that growing the Guiera shrub next to millet increased the production of the food crop by 900 percent.

Richard P. Dick, Professor of Soil Microbial Ecology at Ohio State University, noted while traveling through rural Senegal two decades ago that the Guiera seemed to have no problem growing, despite the unfriendly weather and soil conditions of the area that had eradicated all other plants and made farming impossible.

Dick and his lead collaborator Ibrahima Diedhiou of Senegal University have been working on utilizing the shrub to help locals optimize their crop production.

“People in this part of Africa rely on locally grown crops to survive. Finding ways to increase food production, especially during times of severe drought, is critical,” Dick tells FoodIngredientsFirst.

Sorghum and millet are crops that are essential to the Senegalese as a primary food source. In the African Sahel, where the Guiera plant is found, it is not widely recognized for its potential importance to crops, with farmers in Senegal typically burning shrub biomass and not actively managing the shrubs. However their crops have probably been aided by the shrub for thousands of years without their knowledge, Dick assumes.

Since the discovery, Dick and his team developed an innovative crop management system called the “Optimized Shrub Intercrop System” that uses the shrub and its abilities to supply water during in-season drought.

In addition, the research has shown that shrubs reduce time to harvest by fifteen days and instead of burning, putting leaves and stems back to the soil provides more nutrients for crops and significantly improves soil quality.

Although the system now needs to be tested in collaboration with farmers, the team has high hopes for its potential to improve farming in the dry Sahel region. The shrub is local, free and easy to cultivate, so if the testing goes well, it could revolutionize farming in the region, the researchers say. Yet the testing so far was carried out using only millet crops and one can’t help but wonder if other plants can benefit alike.

“We can only confirm this for millet because the experiment we did use labeled water and this is a very labor intensive and difficult experiment to run. But it is the ultimate experiment to prove water is moving from one plant species to another. So we could only afford to do this once with millet and Guiera with the amount of funding we have had,” Dick says.

He goes on to mention, however, that we can expect positive results with other plants as well.

“We have done research on peanut and find that in dry years the presence of this Guiera likely contributes water as yields are higher with shrubs than without in low rainfall years. There is no reason why other crops cannot benefit. The shrub does all the work and if there are other shallow-rooted plants in the presence of shrubs, they can take advantage of the hydraulically lifted water.”

The next step then would be work with the Sahel region’s farmers to collaboratively test and demonstrate this system. “Our system is an Optimized Shrub Intercrop system where we increased the density to about 1,500 shrub plants per hectare, thus quadrupling the density of what is in a typical farmer field (less than 300 plants per hectare). Farmers do not know how to propagate and raise seedlings of these shrubs and we would need to work with them to implement non-thermal management of coppiced shrub biomass.”

The system that Dick and his team developed is still in the testing phase. “It is important to recognize that at this stage we do not advocate the widespread promotion of this Optimized Shrub Intercrop System, because it takes 2-3 or more years to fully see the benefits.

“Thus, at this stage, we are pushing to do participatory on-farm collaboration with small groups of farmers across the Sahel, to pilot test and monitor the labor issues and agronomic and socio-economic performance of Optimized Shrub Intercropping systems, in order to develop the platforms for scaling and outreach campaigns, after pilot testing,” he concludes.

By Kristiana Lalou