Maize is vital for food systems and rural livelihoods in the Democratic Republic of Congo (DRC). Continuous cultivation depletes soil nutrients, reducing maize production. Inorganic (or mineral) fertilizers provide nutrients rapidly, but their cost and sustainability concerns have prompted interest in alternatives. Biological amendments improve nutrient uptake and soil structure and boost crop resistance, potentially cutting mineral fertilizer use. The present study aims to investigate the direct and residual effects of biological amendments (BAs) on maize productivity in the Eastern DRC, both when applied alone or combined with inorganic fertilizer, with trials conducted in the Kabare, Kalehe, and Ruzizi Plain regions from October 2022 to June 2024. Two trials across four seasons gathered data using a randomized complete block design (RCBD) with nine treatments and three replicates: Control, without fertilizer application; farmer practice; inorganic fertilizer (NPK 17-17-17 and urea); BA_1: Lactobacillus; BA_2: fish serum; BA_3: black soldier fly (BSF) compost; BA_1 + inorganic fertilizer; BA_2 + inorganic fertilizer; and BA_3 + inorganic fertilizer. The results identified three categories: integrated organic and inorganic fertilizers, single applications, and inconsistent uses. The best outcomes emerged from treatments combining Lactobacillus, fish serum, and BSF compost with inorganic fertilizer, positively impacting maize yield parameters. The study confirms that combining biological amendments and mineral fertilizers significantly (p < 0.001) enhances maize productivity in the Eastern DRC. Performance differences across locations emphasize the influence of local soil characteristics and targeted nutrient strategies.

Despite efforts to reduce youth unemployment through agribusiness incubations, significant gaps persist globally and in the Democratic Republic of the Congo (DRC) regarding the efficiency of the incubation value chain model in promoting youth in agribusiness. The study hypothesizes that incubation is most effective when aligning participants with value chains and fostering networks. It examines the effectiveness of the incubation value chain model through Youth-Oriented Outreach Resource Training Centers–Business Incubators (YORTC-BIs) in eastern DRC. It represents the first study conceptualizing YORTC-BIs as value chain architects rather than organizational structures. Using a sample of 310 youths, the study applies descriptive statistics and logistic regression to evaluate the determinants of youth participation in YORTC-BIs, while Oaxaca–Blinder decomposition assessed gender and spatial disparities. A quasi-experimental design combined with enterprise turnover growth analysis and propensity score matching assesses the impact of YORTC-BIs engagement in agribusiness and incubator efficiency compared to non-participants. Network analysis examines incubators’ interaction across value chain segments. Findings indicate that youth engagement in agribusiness is driven by training, assets, role models, and social networks, with gender and regional disparities. Participation in YORTC-BIs increases the likelihood of engagement by 56%, while incubated youth active across multiple value chain segments achieve 23% higher performance. Network analysis shows growing interconnections within the agribusiness system, with production as the central node. Value chain-oriented incubation models outperform standardized approaches, suggesting that context-sensitive, network-based strategies are essential for promoting inclusive agribusiness development and youth employment in fragile economic contexts.