Agronomic Response of Tomato Varieties TOUNVI and COBRA to Organic, Mineral and Integrated Soil Fertility Management in Southern Benin

Abstract

Background: Tomato production in southern Benin is increasingly constrained by declining soil fertility and suboptimal fertilizer management, leading to poor plant growth and low yields. This study evaluated the agronomic response of two tomato varieties, TOUNVI (a local landrace) and COBRA (an improved commercial variety) to different fertilization strategies. Methodology: A split-plot experimental design was used, with variety as the main plot factor and four fertilization treatments as subplots: (T0) no fertilizer (control), (T1) organic fertilizer (compost), (T2) mineral fertilizer (NPK), and (T3) integrated organic–mineral fertilization. Data were collected on vegetative growth parameters—plant height and stem diameter—at multiple stages throughout the cropping cycle, as well as on reproductive traits, including number of flower clusters, flowers per plant, and fruits per plant. Results: Results showed that both fertilization regime and variety significantly influenced growth and yield components. The integrated fertilization treatment (T3) consistently produced the highest vegetative growth across all measurement dates. Under this treatment, the number of fruit per plant recorded by TOUNVI and COBRA were 55.5 ± 0.7 and 49 ± 1.41, respectively. Compared with the control, T3 increased fruit number per plant by more than 85%, indicating a strong yield response to combined nutrient inputs. All fertilized treatments significantly outperformed the unfertilized control in reproductive parameters. COBRA exhibited greater vegetative vigor and higher flower production, whereas TOUNVI demonstrated superior fruit set, particularly under integrated fertilization. Conclusion: These findings highlight the potential of integrated soil fertility management to sustainably enhance tomato productivity in southern Benin, while also underscoring the complementary roles of local and improved varieties in resilient cropping systems.