Variation in runoff and sediment loss in fallow and abandoned farmland in Agoi- Ekpo, Cross River State, Nigeria

A study was carried out to assess soil erosion and associated losses on abandoned cassava farmland, 3-year, 10-year and 5-year fallows in a part of the rainforest zone of southern Nigeria. The study showed that the 5- year fallow yielded the most losses as a result of its scanty herbaceous cover and existence of canopy gaps followed by the abandoned cassava farmland, while the 10-year experienced the lowest losses in runoff and sediment. Runoff loss (F = 16.089; p<0.05) and sediment loss (F = 6.355, p<0.05) varied significantly among the treatments. The study revealed erosional losses occurred in all plots and that fallows with sparse herbaceous cover were less effective in suppressing soil erosion. To reduce unproductive loss of rich topsoil, farmers were encouraged to maintain adequate herbaceous cover during cropping to speed up ecological restoration after land abandonment.Keywords: Fallow vegetation, Soil erosion, Erosional losse

Seasonal Variations in Heavy Metal Status of the Calabar River, Cross River State, Nigeria

The study examined heavy metal status of the Calabar River in Cross River, Nigeria. Surface water samples were collected during the wet and dry seasons for ten months across five stations and analyzed for heavy metal parameters using standard methods. Result showed that the concentrations of iron (Fe), zinc (Zn), manganese (Mn), copper (Cu), lead (Pb) and total hydrocarbon (THC) in the dry and wet seasons were low and within WHO and FEPA tolerable limits The proportion of copper (Cr), cadmium (Cd), barium (B), nickel (Ni), vanadium (V) and mercury (M) were not detected indicating the absence of these metals in the sampled stations. The low levels of heavy metal contents across the sampled stations showed they were not polluted and as such suitable for aquatic live. Independent samples test result indicated seasonal difference in the proportion of Fe, Zn, Cu, Pb and THC (p<0.01).The study identified runoff from industrial, agricultural and residential areas as sources of heavy metal pollution in the wet season and effluent discharges from industrial and municipal wastes as major sources of pollution of the Calabar River in the dry season. To sustain the ecological status of the Calabar River, waste management practice of waste re-use through the use of retention ponds is encouraged