Estimating land degradation neutrality (LDN) using carbon sequestration pedotransfer function on dissimilar land use and land cover in humid tropics

The study assessed land degradation neutrality using carbon sequestration pedotransfer function on dissimilar landuse and landcover in tropical Nigeria. Target sampling technique guided field studies. A 12 year old restored land and a 5 year old degraded land were identified for the study while a natural forested land which served as a tool for comparison was identified and studied. Three profile pits were dug in each identified area except the degraded land where its bank was scrapped to reveal fresh soils. Samples were collected at uniform depth (cm) of 0-15, 15-30, 30-45 and 45-60 and described using FAO guidelines.Soil samples were air dried and sieved for standard laboratory analysis. Data obtained were subjected to descriptive statistics and correlation coefficient. The results showed that all soil variables were moderately skewed (-0.61 to 0.69), while kurtosis (1.5) showed that most soil properties were dissimilarly distributed among land types. Silt, clay, bulk density, organic carbon and effective cation exchange capacity (ECEC) correlated positively (p=0.05) among each other except sand. Assessing land degradation neutrality (LDN), land cover change showed that the restored and forested land had dense vegetation characterized with grooves of bamboo, shrubs and grasses while the degraded land had loss of biodiversity. Land productivity using land degradation index (LDI) showed that the restored land (30.1) recorded great appreciation in basic cations compared to the forested/control (0) and degraded land (-6.8).The restored land (22,490) also sequestered more carbon (t-ha-1), followed by the natural forest land (7,976) and the degraded land (3,820).