Changes in agricultural practices influence how much and at what rate carbon is stored in or released
from soils. We examined the carbon storage at two soil depths (0-5cm and 5-20cm) in four agricultural
practices namely: natural undisturbed forest, Gmelina arborea forest, alley crop farming and sewage
sludge dumpsite in southeastern Nigeria. At both depths the soil ph, bulk density, total porosity,
water holding capacity and sand fraction (gkg-1
) showed low variation while silt + clay fraction was
observed to vary moderately. Total carbon stored in soil was highest in natural uncultivated forest
with 37%, 62% and 27% increase relative to alley cropping, sewage sludge dump and Gmelina arborea
forest, respectively. Results also showed that forests and alley cropping can store large quantities of
C in soils while sewage sludge is not effective in storing large quantities of C