Effect of Microbial Biostimulants on Maize Growth Parameters and Yield in Northern and Central Côte D’ivoire

Abstract

Maize production in Côte d’Ivoire is constrained by declining soil fertility and the high cost of mineral fertilisers. Microbial biostimulants may provide a complementary approach for improving crop performance while reducing dependence on chemical fertiliser inputs. This study evaluated the effects of arbuscular mycorrhizal fungi (AMF) and the plant growth-promoting rhizobacterium Pseudomonas putida on maize growth and yield in northern and central Côte d’Ivoire. Field trials were conducted in Boundiali, Ouangolodougou and Sakassou using the maize variety GMRP 18. Five treatments were assessed: T0, absolute control without fertiliser or biostimulant; T1, 100% recommended fertiliser plus urea; T2, AMF plus 50% recommended fertiliser plus urea; T3, Pseudomonas putida plus 50% recommended fertiliser plus urea; and T4, AMF plus Pseudomonas putida plus 50% recommended fertiliser plus urea. Growth parameters, including plant height, number of leaves, stem collar diameter and leaf area, were measured at 60 days after sowing. Yield components, including ear length, ear diameter, ear weight, number of grains per ear, grain weight per ear and final production, were assessed at harvest. The treatments significantly influenced maize growth and yield parameters. In general, T4 produced the best, or among the best, responses across several measured variables, while T2 and T3 also improved performance compared with the control. The findings indicate that microbial biostimulants, particularly the combined application of AMF and Pseudomonas putida with reduced mineral fertiliser input, may support maize growth and productivity under the studied agroecological conditions.