Journal of Agriculture and Ecology Research International

Sustaining soil fertility in maize producing areas in Kilifi County is a major challenge. The high cost of inorganic fertilizers, shortened fallow period and poor vegetation regrowth has adversely affected natural processes that replenish soil fertility resulting in poor yields. Subsequently, the small scale farmers have resulted to use of locally available chitosan droppings from roof ceilings to address poor soil fertility in maize production. However, there exists no guidelines or recommendations on the amounts of chitosan manure to use to obtain optimal yields. Marwa et al. (2021), indicated that before use of any manure in crop production, trials must be done to establish appropriate amounts to be used. This study was conducted to evaluate the effects of raw chitosan, composted chitosan manure, chitosan liquid tea, DAP fertilizer and control on grain yield, biomass and harvest index of PH-4 maize. A 5x3 randomized complete block design experiment replicated three times was set at Pwani University Crop Science research farm from May 2025 to December 2025. Treatments included, raw and composted chitosan manure, chitosan manure tea, DAP fertilizer and control. Raw and composted chitosan were applied at a rate of 5tons per ha, while DAP fertilizer was applied at a rate of 100kg per ha. Liquid chitosan tea was applied at a rate of 1litre per hill. Data to be collected included plant height, number of leaves, leaf length and breadth, stem thickness, cob numbers, above-ground biomass dry matter, rows per cob, grains per cob, 1000 grain-weight, grain yield and harvest index. Data collected was subjected to Analysis of variance (ANOVA) using Genstat statistics software 14^th edition. The means were separated using Fisher’s Least Significance difference at 5% level of significance and inferences made.  The results indicated that the treatments, had significant effects on grain yield, biomass and harvest index. Composted chitosan recorded the highest significant values for all the tested parameters, except for biomass yield.