Ohio State-Developed Crop Management System Improves Yields and Soil Quality for the West African Sahel

Michelle Brkljacic General

A group of farmers, researchers, students, extension specialists, and NGOs gathered on October 7th for the inaugural Field Day of the Optimized Shrub System (OSS), an innovative management system developed for rainfed crops in the West African Sahel.

The OSS Field Day was held at the École Nationale Supérieure d’Agriculture in Thiès (ENSA), Senegal as part of the Ohio-State led, USAID-funded project titled, “Optimized Shrub System (OSS): An innovation for landscape regeneration and improved resilience for the peanut-basin of Senegal.”

The OSS works by increasing the natural density of two native shrubs (Gueira senegalensis and Piliostigma reticulatum) in farmers’ fields from ~250/ha up to ~1,500/ha and annual incorporation of shrub biomass into the soil instead of the current practice of coppicing the shrubs to the soil surface and burning the residue, depriving soils of much needed organic inputs. Over the span of nearly two decades of research in Senegal, SENR Soil Science Professor and Global Water Institute (GWI) Faculty Advisory Board member Dr. Richard Dick led the development of OSS in collaboration with U.S., Senegalese, and French scientists. GWI Program Manager, Amanda Davey, joined the OSS work in 2011.

Man pointing at sign

Project Co-Director, Dr. Ibrahima Diedhiou described the treatment plots of the long-term Optimized Shrub System research plots at Keur Matar. (Phot credit: Nick roll)

“This Field Day was an important opportunity for us to learn from farmers so we can incorporate their experience before our next steps to scale the OSS system across the Sahel,” said Dr. Richard Dick, Project Director

After a welcome breakfast, the participants were transported by bus to the long-term OSS research plots in the village of Keur Matar. Lead Senegalese researcher and Director of ENSA, Professor Ibrahima Diehdhiou, presented the results of over 20 years’ of research which has shown that OSS dramatically increases soil quality, carbon sequestration (off setting climate change), microbial diversity and activity, nutrient and water availability, and most importantly increased yields – up to three-fold (32+ peer reviewed articles). A truly remarkable finding is that these shrubs “bio-irrigate” crops via hydraulic lift at night; combined with improved soil quality and that OSS reduces time to harvest by about 15 days, OSS greatly buffers crops against in-season drought.

Plants in a field

Millet grown in plus shrub plots under OSS management during the current drought. This plot will produce a harvest as the millet was supported through the drought by the shrub system.

Plants in a field

Millet grown in the no shrub plot under the traditional management system. This growing season experienced drought in the region of the long-term plots. This crop will not produce a harvest.

Dr. Sidy Diakhaté, who conducted his doctoral thesis on the effect of shrubs on nematodes, explained that the presence of shrubs such as Piliostogma reticulatum makes it possible to reduce by more than 30% parasitic nematodes that attack the roots of millet and reduce yield. At the same time, the shrubs help increase the beneficial nematodes that contribute to the availability of nitrogen in the soil. Following, Co-PI Dr. Moussa Diangar, researcher at the Senegalese Institute for Agricultural Research (ISRA), presented his findings that cowpea crops grow more robustly under the OSS system rather than the traditional system.

Man with demonstration table in front of informational banners

Project Co-PI Dr. Moussa Diangar presenting the results of his research growing cowpea using the Optimized Shrub System.

Through the project’s socio-economic research, the team has learned that a barrier to OSS adoption is that farmers do not know how to propagate new shrubs. To that end, Mr. Moussa Dione gave a demonstration on shrub propagation, showing the simple layering technique used to make more shrubs. Another potential barrier is the labor needed to prune and cut the leaves and stems before incorporating them into the soil. Eng. Pape Diop of ISRA demonstrated a shrub shredder machine he designed to address the labor constraint. Eng. Diop’s machine is dual purpose, acting as both a shrub shredder and a chopper to turn crop residue into animal fodder.

The day was not without its adventures, including a brief delay when the bus became stuck. After a short struggle to pull the bus out of the sand, the group headed back to ENSA for a traditional Senegalese meal and tea before heading to the afternoon OSS symposium where PhD student Mariama Dione presented the results of the bio-physical data from 30 farmers piloting OSS, Co-Pi Dr. Katim Toure presented the socio-economic findings from the current pilot study. In addition, participating farmers gave their feedback from implementing OSS over the past three seasons. The day ended with an engaging discussion where there was shared excitement over the next steps for the OSS innovation.

The Secretary General of the largest farmer cooperative organization in Senegal, Federation of NGOs in Senegal (FONGS) congratulated the team on their results and said that he would, “like to establish a partnership between the OSS team and the farmer organizations he represents to advocate for funding to implement scaling of the OSS innovation,” Abdou Hadji Badji, SG FONGS.

“The field day was a great success, evidenced by the engaged discussions and questions in the field and afternoon session – reinforcing stakeholder support and guidance for developing a scaling platform for collaborative OSS implementation with smallholder farmers in Senegal and beyond,” said Dr. Richard Dick.