Effect of Poultry Manure Application on Soil Fertility and Maize Yield in Adamawa State, North East Nigeria

This study evaluates the effect of varying rates of poultry manure application on soil fertility parameters and maize grain yield in Adamawa State, located in Nigeria's North East geopolitical zone. Poultry manure is an abundant and nutrient-rich organic material in the North East zone, and its systematic application to farmland represents a practical strategy for improving soil fertility and reducing dependence on costly synthetic fertilisers by smallholder farmers. A field experiment was established using a randomised complete block design with five poultry manure treatment rates of 0, 2.5, 5.0, 7.5, and 10.0 tonnes per hectare, applied to maize plots at Mubi South local government area over two cropping seasons. Pre- and post-planting soil samples were collected and analysed for pH, organic carbon, total nitrogen, available phosphorus, and exchangeable cations. Maize grain yield was determined at harvest. Findings revealed significant improvements in soil organic carbon, total nitrogen, and available phosphorus at rates of 5.0 tonnes per hectare and above after two seasons. Soil pH increased marginally from 5.8 to 6.3 at the 7.5 tonne rate, approaching the optimal range for maize production. Maximum grain yield of 3.8 tonnes per hectare was achieved at the 7.5 tonne rate, representing a 124 percent yield increase over the unfertilised control. The study recommends 5.0 to 7.5 tonnes per hectare of poultry manure as the economically optimal application rate for maize production in the North East zone. Keywords: poultry manure, soil fertility, maize yield, Adamawa State, organic amendment.