Abstract

Most agricultural soils contain only a small proportion of carbon and nitrogen, but this small amount plays a very large role in soil quality. However, the estimation of carbon and nitrogen storages in rain forest area of Nigeria has not been adequately documented. A study was conducted to examine the effects of climate change on the Carbon and Nitrogen storages of soils derived from Coastal Plain Sands (CPS), Beach Ridge Sands (BRS) and Sand Stone/Shale (SSS) parent materials in Akwa Ibom State. Secondary soil data of organic carbon, and bulk density as well as climatic data of 2004 to 2014 were used. Organic C stock and SON were calculated as product of soil organic carbon (or total N) contents, bulk density and soil depth. Data were analysed using descriptive statistics, regression analysis and ANOVA at α0.05.Organic C stocks on the surface (0-15 cm) soil depth were 44.13±15.91, 43.89±17.39 and 52.40±18.02 Mg C ha-1 for CPS, BRS and SSS, respectively. The corresponding values for subsurface depth (15-30 cm) were 28.30±9.58, 24.83±8.93 and 26.37±5.74 Mg C ha-1. However, N stocks at 0-15 cm soil depth were 3.37±0.90, 3.19±0.94 and 3.56±1.00 Mg N ha-1 for CPS, BRS and SSS, respectively. Whereas in the 15-30 cm soil depth, SON was 2.07±0.55, 2.00±0.58 and 2.04±0.56 Mg N ha-1 for the respective parent materials. Highly significant SOC stock of 78.90 Mg C ha-1 occurred in 2005 in SSS, while the least stock of 23.71 Mg C ha-1 occurred in 2007 CPS. Across the parent materials, organic C stocks increased as rainfall decreases. Whereas, N stocks increased with decrease in relative humidity. Change in climate significantly affected soil organic carbon and nitrogen storages in Uyo, Nigeria.