Dynamics of Nitrate- Nitrogen of Poultry and Sheep Manures Amended Degraded Ultisols in Ihiagwa, Southeastern, Nigeria

Nitrogen is the most important nutrient element whose deficiencies have been widely reported and constitute crop most limiting factors in the tropics. This experiment was a 3 × 3 factorial arranged in randomized complete block design, replicated three times. The rates equivalent of 0, 30 and 60 % N of both poultry and sheep manures were incorporated. Nitrate- nitrogen (NO3–– 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 early and late seasons of 2019 and 2020. Soil NO3–– N was different with poultry and sheep manures rates only and the interaction of both manures at various soil depths, seasons and years. Concentrations of NO3–– N in most soil depths at both seasons and years were better with 30 % then 60 % N of poultry and sheep manures alone and with interactions of both manures (P30S60) better than single incorporation. Averaged over soil depths and seasons after manure applications, the soil NO3–– N was higher in late than early seasons and in 2020 than 2019. The result showed that NO3–– N decreased with increase in soil depth. Averaged over soil depths, manure rates, seasons and years, concentrations of NO3–– N varied and better at 12th week after manure application for 2019, but first week in 2020. Consequently, this research revealed that addition of poultry and sheep manures improved soil NO3–– N than the control with integration better than single dose. Further study is recommended to illuminate this fact.