Comparative Effects of Four Liquid Fertilizers on the Growth and Yield of Pepper (Capsicum annuum L.) under Soilless Cultivation in Southern Côte d’Ivoire

Abstract

In the face of growing demand for vegetable crops, particularly solanaceous species, the excessive use of synthetic fertilisers and the degradation of arable soils are major constraints on agricultural production in West African urban and peri-urban areas. Soilless cultivation is therefore gaining importance as an alternative production system that is less dependent on soil quality. This study compared the effects of four liquid fertilisers - two organic (a poultry manure extract and a manure-based fertiliser) and two mineral fertilisers (Nutrigofol 8-8-8 and NPK 12-22-22, with the latter serving as the control) - on the growth and yield of pepper grown under soilless conditions, with the broader aim of identifying nutrient solutions that could reduce growers’ dependence on chemical fertilisers. The trial followed a randomised complete block design with four replicates. Treatment had a significant effect on most growth and yield parameters (p < 0.001). The organic fertilisers, particularly the poultry manure extract, produced significantly higher values than the mineral fertilisers for floral bud number, fruit number, fruit mass, and estimated yield. Estimated yield reached 5.11 t ha⁻¹ with the poultry manure extract, followed by the manure-based fertiliser (3.69 t ha⁻¹), Nutrigofol 8-8-8 (2.81 t ha⁻¹), and NPK 12-22-22 (2.64 t ha⁻¹). Because no unfertilised control was included, these results describe the relative performance of the four fertilisers rather than their absolute agronomic efficiency. Within this comparative scope, the findings indicate that organic nutrient solutions derived from locally available livestock waste can support pepper productivity in soilless systems at least as well as, and for several parameters better than, the mineral fertilisers tested. Valorising such organic waste as low-cost biofertilisers could contribute to more affordable and resilient vegetable production for expanding West African cities, provided these trends are confirmed against an unfertilised control and under real production conditions.