Published on August 19 in the journal *Frontiers in Agronomy*, a study examines the effectiveness and economic viability of integrated management programs aimed at restoring soil health, agroecological functions, and coffee productivity in these degraded systems. According to the study, the experiment took place over 34 months, from September 2022 to June 2025, at the Mulungu research station in South Kivu, in the eastern part of the Democratic Republic of the Congo.
This study explores the combination of five integrated farming practices, including cover crops or intercrops with a single application of cow manure, the conservation of crop residues, and the establishment of elephant grass (Pennisetum purpureum) hedgerows around plots and Calliandra hedgerows around blocks.
The PCI treatments were distinguished by the following cover or intercrop crops: horse bean (Mucuna pruriens), bush crotalaria (Crotalaria grahamiana), elephant grass, a horse bean–common bean (Phaseolus vulgaris) rotation, and banana as an intercrop. A control plot with only Calliandra along the edges of the blocks was included.
According to Dr. Ntamwira Bagula Jules of the National Institute for Agronomic Studies and Research (INERA) and the Biodiversity International–CIAT Alliance, a co-author of this study, coffee is an important source of income for a large portion of the population in eastern DRC. Nevertheless, yields are declining due to the depletion and degradation of farmland, caused in particular by continuous plowing, slash-and-burn farming, bushfires, and deforestation.
Finally, the study highlights that the combination of coffee and banana trees yielded promising economic results. The findings reveal a significant improvement in coffee yield in certain treatments. The study also notes that the management systems tested reduced coffee tree mortality and increased relative diameter growth at 34 months. The study indicates that 45% of coffee trees had died in the control plots after this period, whereas the mortality rate ranged from 10 to 30% in the plots that benefited from integrated management.
Changes in chemical properties were observed during the study period, the study notes, while physical and biological indicators showed signs of recovery, including a decrease in temperature in the plots and an increase in earthworm abundance.
Bagula Jules noted in an email that, to restore degraded fields, Mucuna and beans were reintroduced into a crop rotation, along with Crotalaria juncea and Pennisetum purpureum in the aisles or as hedges, as well as a Calliandra hedge and banana trees as shade crops.
He explains that dwarf beans are grown in rotation with Mucuna. Bean residues and Mucuna biomass are returned to the soil as mulch. Pennisetum purpureum, planted as an interrow or hedge crop at 25 × 25 cm, is cut regularly and applied as mulch around the coffee trees. Calliandra, planted along the field edges at 1-meter intervals, fixes nitrogen and is used as manure, mulch, or fodder when pruned. He adds that banana trees provide shade and mulch in this intercrop system.
He states that these techniques have enabled cover crops and grasses to improve soil health, nutrient levels, earthworm populations, soil moisture and temperature, as well as crop vigor and income over a three-year period. They have also significantly reduced labor costs and limited the use of chemical pesticides.
According to Ghislain Kamondo, Executive Director of Congo Agri Platform a consortium of Congolese coffee and cocoa agricultural cooperatives based in the DRC that did not participate in the study agroforestry helps restore cocoa fields and improve their profitability.
Written by Victoire Katembo Mbuto
