Search

This current study investigated the relationship between soil organic carbon (SOC) and terrain derivatives on soil developed on dissimilar lithology while comparing the best modelling approach. Sixty (n = 60) bulk soil samples were taken from the depth of 0–30 cm according to five identified basement complex materials and analyzed for SOC. The models considered are ordinary kriging (OK), principal components kriging (PCA_OK) and regression kriging (RK). For the prediction's accuracy, 2-fold, and leave one out (LOOCV) cross-validation was carried out. The study indicated SOC in soil developed on granite gneiss (2.12%) and Biottite hornblende gneiss (2.05%) to be significantly (p

Soil properties can be influenced by slope location due to erosion, deposition, and mass movement. There are conflicting findings regarding the impact of the slope position on soil properties and elemental concentrations. This study aimed to examine the influence of slope position on the variability of soil properties and elemental concentrations along a hillslope landscape, using different multivariate approaches. This research was conducted in three distinct locations within the Cross River State, Nigeria: Ishibori in Ogoja, Agoi Ibami in Yakurr, and Mfamosing in Akamkpa. Three profile pits were dug on the crest, two on the middle slope, and three on the valley bottom, resulting in eight pits representing these locations. Fifty-three soil samples were collected from these pits and subjected to laboratory analyses. The lowest values were obtained for Bd, sand, and pH at all three slope positions. At the same time, the highest values were obtained for AP, SOC and Mn at the three different slope positions (crest, middle slope, and valley bottom). Soil properties, such as exchangeable acidity, bulk density, clay content, sand content, and soil organic carbon, were positively or negatively correlated (p < 0.05) with soil depth and elemental concentrations, depending on the location in the landscape. Exploring the interrelationship via a structural equation model (SEM), we observed that clay showed a strong positive correlation with sand and a moderate to weak negative correlation with sand and silt. The correlation coefficients between the studied slope positions were –0.88, –0.78, and –0.51, respectively. These results indicate that as the soil material at the crest decreased, there was a corresponding decrease in the materials at the middle slope and valley bottom. In the ANOVA, bulk density values in the crest and middle slope were comparable, but higher than those in the valley bottom soil. The potassium concentration was significantly different between the crest and middle slopes. Based on these findings, it can be concluded that topography significantly affects soil properties and that these differences should be considered when selecting and managing land for agricultural purposes. To improve soil fertility and productivity, it is recommended to implement proper soil management practices, such as nutrient management and erosion control, to reduce the impact of topographical differences on soil properties. [ABSTRACT FROM AUTHOR]

This study investigated the current state and pollution loads of heavy metals in soils developed on diverse parent materials in southeastern Nigeria. Cu, Mn, Zn, Fe and Al were analyzed to estimate pollution loads and ecological risk of the area. The result showed soils developed on granite gneiss to have a higher concentration (measured in mg kg−1) of Cu (1.79), Mn (78.39) and Zn (28.53), while soils developed on Biotite hornblende gneiss and quartz-mica-schist had a higher concentration of Fe (≥18) compared with other parent materials. The contamination factor for Fe, Zn, Mn and Cu was low, whereas Al was moderately to considerably contaminated except for soils in S2 (0.362), S3 (0.662), S6 (0.142), S9 (0.661), S11 (0.803) and S15 (0.499). The result of the pollution load index indicated an unpolluted condition (PLI < 1). Excluding Al, the soils were practically uncontaminated with Zn, Cu, Fe and Mn, based on the Geo-accumulation index and Quartz-mica-schist was enriched by Zn in S6 (1.325) and showed low ecological risk (Er < 40) and (IR < 150). Hence, the soils in the studied communities are still in a safe state to be used for crop cultivation without any fear of metal contamination. [ABSTRACT FROM AUTHOR]