Comparison of the Effects of Azolla Filiculoides, Chromolaena Odorata and a Mineral Fertilizer on Agro-morphological Parameters of Potato (Solanum tuberosum L.) in the Humid Tropical Zone of West-Central Côte d’Ivoire

Abstract

Potatoes (Solanum tuberosum L.), a major food crop worldwide, are enjoying increasing popularity in West Africa, particularly in Côte d'Ivoire, where they represent a strategic alternative to food insecurity. However, its production remains limited by low soil fertility and unsustainable fertilization practices. The aim of this study was to compare the efficacy of two biofertilizers (Azolla filiculoides and Chromolaena odorata) with that of a mineral fertilizer NPK 15-15-15, on the agro-morphological growth of the Bintje variety, under the humid tropical conditions of central-western Côte d'Ivoire. The trial was conducted in Daloa, from March to June 2025, on a sandy-clay textured soil (37.09% clay; 46.84% sand), with a slightly acid pH (5.95) and moderate organic matter content (2.3%), but with high deficiencies in assimilable phosphorus (0.57 mg/kg), magnesium (0.6 cmol/kg) and calcium (3.175 cmol/kg), as well as low base saturation (33.9%). The experimental design was a completely randomized Fisher block, with four treatments (control, A. filiculoides, C. odorata, NPK) and five replicates. Biofertilizers were each applied at 3 t/ha, and NPK at 175 kg/ha. Parameters measured included crown diameter, plant height, number of leaves and stems, and leaf dimensions. Data were analyzed by one-factor ANOVA, followed by Fisher's 5% test. Results show that NPK significantly improved vegetative growth: maximum collar diameter (0.7 cm), average height of 74.4 cm and highest number of leaves (13.86). A. filiculoides produced intermediate performances (0.64 cm; 64.52 cm), followed by C. odorata, which produced lesser effects but greater than the control. The number of stems did not vary significantly between treatments. Although biofertilizers are less effective than NPK in the short term, their properties (atmospheric nitrogen fixation for A. filiculoides, mineral richness and improved soil structure for C. odorata) make them promising alternatives for reducing dependence on chemical fertilizers and promoting sustainable potato fertilization in the humid tropics.