Assessment of Soil Quality Status under Different Land-Use in Akpabuyo Local Government Area of Cross River State-Nigeria

The conversion of natural forest into other forms like pasture or croplands is of considerable concern worldwide in the context of environmental degradation and global climate change. This study is aimed at examining variations in soil properties in continuously cropping and forested plots in parts of southern Cross River State – Nigeria. To achieve this, four transects were established in the cardinal directions due to break in slope of the land terrain and nine soil profiles comprising two in each direction and the starting point were selected along the transects. Soil samples were taken from the different horizons. The samples were stored in polyethylene bags and taken to the laboratory. In the laboratory, the samples were air-dried, crushed and allowed to pass through a 2mm sieve and analysed using standard methods. The method of statistical analysis employed was the pair-wise t-test, otherwise known as the paired comparison as described by Snedecor and Cochram to determine the significant differences that existed between the landuse types on the measured soil properties in the study area. The index of deterioration (DI) was also calculated for the soil properties to determine the rate of deterioration. The result of the analysis of chemical properties shows that organic matter in the soil under continuous cropping had mean values and SE of 3.8±0.6 and 2.0±0.4 whereas soils under forest plot had mean values and SE of 13.0±1.9 and 2.9±5.0 for topsoil and subsoils respectively. There was a significant difference in the soil pH between the two land use types. The forest plot had a mean and SE value of 5.3±0.08 and 5.2±0.06 while the continuous cropping plot had higher pH values of 3.5±1.2 and 3.1±1.0 for both the topsoil and subsoil respectively. EC, moisture content, total nitrogen, exchangeable calcium, exchangeable magnesium and available phosphorus were higher in soils under forest plot than the soils under continuous cropping while exchangeable sodium was higher in soil under continuous cropping of arable crops. The results show that silt, clay, organic matter, electrical conductivity, total nitrogen, available phosphorus, exchangeable calcium and magnesium shows deterioration indices above 50%. The result further revealed that the soils under investigation have not only deteriorated but degraded as some of the elements have negative (DI). Therefore, there is the need for appropriate soil management strategy to be put in place in order to sustain food production in the study area.