Migration of Soil Ammonium- Nitrogen with Amended Poultry and Sheep Manures in Ultisols of Ihiagwa, Southeastern Nigeria

Soil management to synchronizing nutrient release with crop uptake is essential for sustainable plant production and environmental quality. Ammonium- nitrogen (NH4+- N) dynamics of poultry and sheep manures amended Ultisols in Ihiagwa, Southeastern Nigeria were evaluated. Their levels equivalent to 0, 30 and 60 % N of both poultry and sheep manures were applied in a 32 factorial arranged in randomized complete block setup with three replications. The NH4+- N was determined from four soil depths (0 – 5, 5 – 10, 10 – 20 and 20 – 40 cm) at different weeks (1, 2, 3, 4, 6, 8 and 12 weeks) after manures application (WAMA) in wet and dry seasons of 2019 and 2020. Soil NH4+- N differed with rates of poultry and sheep manures only and the integration of both manure at various soil depths, seasons and years. Concentrations of NH4+- N in most soil depths at both seasons and years were better with 60 % then 30 % N of poultry and sheep manures alone and with integrations of both manures better than single applications. Averaged over soil depths and periods after manure applications, soil ammonium- nitrogen was better in wet than dry seasons and in 2019 than 2020. Averaged over soil depths, manure rates, seasons and years, concentrations of NH4+- N varied and better at 3rd WAMA. Equally, concentrations of NH4+- N decreased down soil depths. Generally, good soil nutrient management will be useful for efficiency of nutrient and sustained crop yields. Further research is needed on the field to substantiate the findings.