The declining yields associated with low soil fertility in the West African sub-region can be halted by using organic resources and mineral fertilizers to improve adverse soil conditions. Field experiments were conducted in seven locations in Osogbo, Nigeria to assess the impact of poultry manure (PM) and mineral fertilizer (MF) applied separately and in combination (PM+MF) on the grain yield of maize (Zea mays, var. TZEE 1-Y) in soils of low fertility. The PM and MF were applied separately at 90 kg N ha-1; each type supplied 45 kg N ha-1 in the PM+MF treatment. A control was included for comparison. Results showed that maize grain yield varied between 200 and 2521 kg ha-1. On average, PM increased grain yield by 68%; combined PM and MF increased it by 80% whereas MF increased it by more than 100% when compared with the control. A comparison of the treatments other than the control showed no significant differences among them but, on absolute terms, the grain yield obtained with MF was slightly higher than those of the other treatments. Generally, the grain yield was low indicating the need for adequate rehabilitation of these soils for meaningful maize production. Therefore, further studies are required to understand all the yield-limiting factors in order to develop appropriate management options.
Keywords: Soil characteristics, soil fertility management, organic inputs, fertilizer application