Growth and yield response of maize to integrated nutrient management of chicken manure and inorganic fertilizer in different agroecological zones.

The productivity of maize, an essential staple food crop in Africa, is severely constrained by the declining fertility of the soil. The combined use of organic and inorganic fertilizers could ameliorate this challenge in a sustainable way to boost maize productivity. Two field trials were conducted at Ashanti -Mampong and Damongo, in the transitional and Guinea Savannah agroecologies of Ghana respectively, to assess the influence of sole and integrated application of chicken manure and NPK fertilizer on the growth and yield of maize. The treatments included two maize varieties; and and five fertilizer rates; 3 t/ha chicken manure (CM), NPK (65:38:38 kg ha NPK), ½ CM + ½ NPK and ¾ CM + ¼ NPK and control (no fertilizer). A 2 x 5 factorial randomized complete block design with three replications was used. Significant variations (p < 0.05) were revealed between varieties, fertilizer types and their interaction effects for phenological, growth and yield of maize in both locations. The superiority of the integrated application of NPK and chicken manure was also visible in the vegetative parameters such as plant height, number of leaves and shoot dry weight of the maize plants given them the comparative advantage to assimilate more photosynthates for partitioning to the ears and grains. Obatanpa treated with ½ CM + ½ NPK produced the highest yield of 4661.1 kg ha, which was 29.6 and 29.9 % higher than the same variety grown on sole NPK and sole chicken manure, respectively at Damongo. Abontem treated with ¾ CM + ¼ NPK recorded a grain yield of 4479.3 kg ha, 11.7 % higher than the sole NPK and 10.3 % higher than the sole CM at Damongo. Similarly, Obatanpa grown on the ½ CM + ½ NPK recorded the highest grain yield of 4349.3 kg haat Mampong followed by Abontem treated with the sole NPK (4267.1 kg ha). Sole NPK and the combined application of NPK and chicken manure gave comparable responses for vegetative traits while the integrated application proved superior for grain yield of maize across the two agroecologies.