EVALUATION OF SOIL ORGANIC CARBON, NITROGEN, AND AVAILABLE PHOSPHORUS AT THE NEWLY ESTABLISHED NOUN RESEARCH FARM, RIGACHIKUN, KADUNA STATE

This research was carried out in 2023 at the newly established NOUN Research Farm in Rigachikun, Kaduna State, to assess the levels of soil organic carbon (SOC), total nitrogen(N), and available phosphorus (P) within the topsoil layers. A total of 12 composite soil samples were gathered from selected plots at two different depths: 0–15 cm and 15–30 cm. The samples were analyzed using established laboratory techniques: the Walkley-Black procedure for SOC, the Kjeldahl method for total nitrogen, and Bray-1 extraction for available phosphorus. The findings revealed a steady decline in nutrient concentrations with increasing depth. At 0–15 cm depth, the mean values were 1.21% for SOC, 0.095% for total nitrogen, and 7.42 mg/kg for available phosphorus. At the 15–30 cm depth, the values dropped to 0.84% for SOC, 0.065% for nitrogen, and 4.91 mg/kg for phosphorus. Spatially, all three nutrients also showed a declining trend from the northern to the southern sections of the farm. Overall, the concentrations of SOC, N, and P were below the critical limits established for optimal crop production in the Nigerian Savanna zone. These results highlight the necessity for enhancing soil fertility through the addition of organic matter, implementation of cover cropping, and the use of both organic and inorganic fertilizers to promote sustainable crop yield on the farm.