Climate-smart agriculture (CSA) is one of the innovative approaches for sustainably increasing the agricultural productivity, improving livelihoods and incomes of farmers, while at the same time improving resilience and contributing to climate change mitigation. In spite of the fact that there is neither explicit policy nor practices branded as CSA in Democratic Republic of Congo (DRC), farmers are utilizing an array of farming practices whose attributes meet the CSA criteria. However, the intensity, distribution, efficiency, and dynamics of use as well as the sources of these technologies are not sufficiently documented. Therefore, this review paper provides a comprehensive evidence of CSA-associated farming practices in DRC, public and private efforts to promote CSA practices, and the associated benefits accruing from the practices as deployed by farmers in the DRC. We find evidence of progress among farming communities in the use of practices that can be classified as CSA. Communities using these practices are building on the traditional knowledge systems and adaptation of introduced technologies to suit the local conditions. Reported returns on use of these practices are promising, pointing to their potential continued use into the future. While progressive returns on investment are reported, they are relatively lower than those reported from other areas in sub-Saharan Africa deploying similar approaches. We recommend for strategic support for capacity building at various levels, including public institutions for policy development and guidance, extension and community level to support uptake of technologies and higher education institutions for mainstreaming CSA into curricula and training a generation of CSA sensitive human resources.

Concerns have been raised on the effectiveness and sustainability of Soil and Water Conservation (SWC) practices as adaptation options to climate change and high intra– and inter–annual rainfall variabilities in eastern Democratic Republic of Congo (DRC). This study was conducted in the Ruzizi Plain, a dryland area, to assess the performance of maize (Zea mays L.) under two Representative Concentration Pathways (RCP 4.5 and 8.5) and two SWC practices (tied ridges and conventional tillage). The AgMIP’s Regional Integrated Assessment (RIA) approach was used to simulate Water Use Efficiency (WUE) under the Cropping System Model–Crop Environment Resource Synthesis (CSM–CERES–Maize) of the Decision Support System for Agro–technology Transfer (DSSAT). The model was calibrated using experimental data from nine cropping seasons (2011–2018) and 100 farms. The model sensitivity was assessed as a function of temperature, water, and SWC practices for the same environments. Initial conditions of crop management practices were used as input data for CSM–CERES–Maize. Current climate data were extracted from AgMERRA datasets corrected with local data for the period of 1980 to 2021. Future climate projections (2022–2099) were obtained after down−scaling the data from the 29 General Circulation Models (GCMS) of Coupled Model Intercomparison Project 5 (CMIP5) and subsetted to five GCMs based on climate regimes. GCMS results were a strong indicator that climate change in this DRC dryland will result in an increase in average annual temperatures for both RCP 4.5 and 8.5, with the highest increase (3.05 °C) under hot/dry conditions for RCP8.5 and the lowest (1.04 °C) under cool/dry conditions for RCP 4.5. All the models selected for five climate regimes for 2022–2099 showed no change in the rainfall trends for RCP 4.5 (p > 0.05). The models projected yield declines of 5–25%, with less yield losses under tied ridges as an adaptation practice. The use of efficient SWC practices could therefore be a promising strategy in reducing potential losses from climate change in drylands of eastern DRC.

Maize (Zea mays L.) productivity is constrained by water shortages in the predominantly rainfed agriculture of the tropical semi-arid Ruzizi Plain, in the eastern Democratic Republic of Congo (DRC). The region is characterized by a high seasonal and inter-annual rainfall variability and a frequent occurrence of consecutive dry days within growing seasons. Consequently, planning water utilization in rainfed agriculture has become complex, as appropriate soil water conservation (SWC) practices are lacking among most smallholder farmers. Identifying practices that increase water use efficiency (WUE) along the slope gradient is crucial for supporting maize production in the region. In this study, we assessed, for three growing seasons, the effectiveness of two SWC practices (tied ridges and Zai pits) in improving the WUE of two maize varieties along three slope gradients (0–2, 2–8, and 8–15%) in the tropical semi-arid Ruzizi Plain. In this area, rainfall amounts (142–289 mm) were consistently below the evapotranspiration demands (356–533 mm) across the three growing seasons. Tied ridges recorded the highest grain yield (2.16 t ha⁻¹) and WUE (15.23 kg mm⁻¹), especially at low slopes, when compared to Zai pits and conventional tillage. For all SWC practices, WUE decreased with the slope gradient (p < 0.01). Furthermore, a decrease in stored soil water (SWS) at silking and maturity stages (milk, dough, and dent stages) negatively affected the WUE. The variety had no significant effect on grain yield and WUE. Root biomass (RBM), shoot biomass (SBM), and leaf area index (LAI) at the flowering stage were the most associated with the WUE (R² = 58.5%). In conclusion, tied ridges showed potential for improving maize WUE and yield in the water-deficient conditions that characterize the Ruzizi Plain, and could be promoted to improve the maize productivity among smallholder farmers.