STAGE-SPECIFIC COCOA SEEDLING RESPONSES TO MYCORRHIZA AND NPK FERTILIZATION

Cocoa seedling quality depends on efficient nursery nutrition, but the benefits of biological and mineral inputs may vary across early growth stages. This study evaluated stage-specific growth responses of cocoa seedlings (Theobroma cacao L.) to mycorrhiza and NPK fertilizer. A 3 x 3 factorial randomized block design with three replications was used, combining mycorrhiza at 0, 40, and 50 g/polybag with NPK 16:16:16 at 4, 6, and 10 g/polybag. Plant height, leaf number, leaf length, and stem diameter were measured at 2-12 weeks after planting (WAP), while root volume was assessed at 12 WAP. Analysis of variance was followed by Duncan's Multiple Range Test at 5% when significant. Mycorrhiza did not significantly affect any measured trait, and no mycorrhiza x NPK interaction was detected. In contrast, NPK significantly affected leaf number from 4 to 12 WAP and leaf length at 4, 6, and 8 WAP. At 12 WAP, 10 g NPK produced 9.96 leaves, while at 8 WAP it produced the greatest leaf length (6.93 cm); plant height, stem diameter, and root volume remained statistically unchanged. These results reveal a stage- and organ-specific nutrient response: NPK first enhanced leaf development without producing parallel short-term gains in structural or root traits. Under the tested nursery conditions, increasing mineral nutrition was more immediately effective than mycorrhizal inoculation, while longer-term studies should verify root colonization and nutrient status.