Asian Journal of Soil Science and Plant Nutrition

Aims: To evaluate the efficacy of poultry droppings amended cocoa pod husk and rice mill wastes, as a substitute for costly inorganic fertilizers on some soil properties and yield of maize.

Study Design: Experiment was laid in randomized complete block design.

Place and Duration of Study: Two year field study was conducted at the Research Farm of the Cross River University of Technology during 2019 and 2020 cropping seasons.

Methodology: Two compost types: cocoa pod husk and rice mill wastes both amended with poultry droppings at the ratio of 3:1 for cocoa pod husk + poultry droppings and rice mill waste + poultry droppings respectively. Each compost type was applied at rate of 2.5, 5.0, 7.5 and 10 t ha^-1 with absolute control (0 t ha^-1 compost) and optimal control NPK 20.10.10 at 300 kg ha^-1 making a total of 10 treatments replicated three times. The effect of the amendments were assessed on soil pH, OM, N, P, exch. Ca, K, Mg, EA, ECEC and maize yield.

Results: The compost rates increased soil pH, OM, N, P and the exch. K, Ca, EA, and ECEC over the pre-treatment soils and the controls. Cocoa pod compost amendments with poultry droppings at rate of 7.5 t ha^-1 produced highest plant dry matter 8.21gplant^-1 and 8.08 gplant^-1 in 2019 and 2020 (P = .05) respectively and the highest grain yield of 3.92 t ha^-1 and 3.89 t ha^-1 respectively in 2019 and 2020. The least grain yield was in the absolute control, which yield was 0.38t ha^‑1 and 0.42 t ha^-1, respectively in 2019 and 2020.

Conclusion: Amended cocoa pod husk compost is a suitable soil amendment for optimum yield of maize and improvement of soil chemical properties in the study area and a substitute for mineral fertilizers for resource poor farmers.