Current Research on Geography, Earth Science and Environment Vol. 9

Impact of Open Dumpsite Wastes on Soil Quality in Akwa Ibom State, Nigeria: Implications for Environmental Sustainability and Agriculture

Bassey U. Udo — 2026-08-03

Open waste disposal systems have raised significant environmental concerns because of their potential to degrade soil quality. This study assessed the effects of waste dumpsites from auto mechanic (A), abattoir (AB), and paint processing (P) activities on soil quality. A control area (C), with no known waste contamination, was selected for comparison. Soil samples were collected from three depths (0-20, 20-40, and 40-60 cm) at the dumpsites after (waste removal) and at the control site, and were analyzed using standard laboratory methods. Soil quality indicators associated with nutrient availability, namely soil texture, pH, organic carbon (OC), and total exchangeable bases (TEB), as provided by the Harmonized World Soil Database (HWSD), were used for quality assessment. The results showed that waste deposits significantly altered the physicochemical properties of the soils. Particle size distribution analysis indicated that the soils were predominantly sandy, consistent with their coastal plain sand origin. The pH values of the impacted soils increased to 7.36, 7.99, and 6.49 for A, P, and AB, respectively, compared with 4.63 for C, indicating a shift from acidic to near-neutral (AB) and alkaline conditions (A and P). OC levels were significantly higher in A and AB, suggesting organic matter accumulation; however, these elevated levels may not necessarily indicate improved soil fertility because of possible contamination and low-quality organic residues. Positive correlations between measured indicators in waste materials and impacted soils demonstrated the influence of waste composition on soil properties. The study concludes that open dumpsites negatively affect the soils they occupy, reduce soil quality, and pose risks to agricultural and environmental sustainability. Engineered landfills and eco-friendly remediation techniques, such as phytoremediation, are recommended.

WRSI-Based Rainfall Deviation Thresholds for Monitoring Drought-Induced Water Stress in Kharif Pulse Crops

G. S. Pratyusha Kranthi — 2026-08-03

Rainfall variability is a major source of water stress in rainfed pulse production during the kharif season. This study evaluated whether rainfall-deviation thresholds derived from the Water Requirement Satisfaction Index (WRSI) could support drought-related crop-condition monitoring in Telangana, India. Blackgram, greengram and redgram were examined at 20 representative locations in Medak, Warangal and Mahabubnagar districts, respectively. Gridded rainfall and maximum and minimum temperature data for 2000–2015, together with soil information, were used in a soil-water-balance framework to estimate rainfall deviation, potential crop evapotranspiration, actual crop evapotranspiration and seasonal WRSI. Rainfall-deviation frequencies were assessed for 2000–2016. Deficit rainfall occurred more frequently at the blackgram locations, whereas normal rainfall was more common at the greengram and redgram locations. WRSI classifications indicated predominantly mediocre crop conditions for blackgram and average-to-good conditions for greengram and redgram. The coefficients of determination for rainfall–WRSI relationships ranged from 0.26 to 0.77 for blackgram, 0.35 to 0.94 for greengram and 0.57 to 0.96 for redgram. Rainfall-deviation thresholds for blackgram were broadly interpretable across the assessed soil conditions, while thresholds for greengram and redgram varied with soil type and depth. The findings indicate that WRSI-based thresholds may assist comparative monitoring of drought-induced water stress when crop characteristics and soil water-holding conditions are considered.

Rainy Season Dynamics of Phosphorus Fractions in Lake Toho Sediments and Surrounding Agricultural Soils

Lyde Tometin — 2026-08-03

Phosphorus enrichment in cultivated soils adjacent to surface waters can increase nutrient transfer and eutrophication risk, especially during rainy periods. This study evaluated the mobility and bioavailability of phosphorus in soils surrounding Lake Toho, southern Benin. Samples were collected from 13 sites and analysed for pH, moisture, organic matter, total phosphorus and operationally defined phosphorus fractions. Soil water pH ranged from 6.25 to 8.30, indicating weakly acidic to weakly basic conditions. Moisture varied from 1% to 38%, while organic matter ranged from 40.30% to 49.70%. Total phosphorus concentrations ranged from 1,049.74 to 28,436.52 µg g⁻¹ and were generally higher in the upper horizons. Phosphorus occurred as labile, iron-bound, aluminium-bound, calcium-bound, organic and residual fractions. Organic and residual phosphorus were the dominant forms overall, whereas labile and other potentially mobile fractions were detected across the sampled horizons. Correlation and principal component analyses indicated relationships among total phosphorus, residual phosphorus, labile phosphorus, organic matter, moisture and pH-related calcium associations. The results suggest that cultivated soils around Lake Toho contain substantial phosphorus stocks influenced by agricultural inputs, parent material and soil properties. During rainfall and runoff events, part of these stocks may be transferred towards the lake. Continued seasonal monitoring and improved nutrient management are therefore needed to reduce potential phosphorus losses while maintaining soil fertility. PCA confirms the consistency of the results and effectively synthesizes the key agronomic and environmental indicators essential for sustainable nutrient management. This analysis structures data variability by highlighting the predominant yield factors.