Physicochemical and Biological Properties of Some Internal Valleys Soil in Wadi Al-Shatii, Libya

Abstract

Newly formed Entisols are prevalent in the topographically lower regions of the Wadi Al-Shati basin. As immature soils, they are characterized by low nutrient content essential for plant growth. The quantity and quality of these nutrients are significantly influenced by the soil's physicochemical and biological properties, such as texture, structure, bulk and particle density, and porosity. Consequently, these properties directly impact the basin's biodiversity and vegetative cover. Understanding these characteristics provides crucial insight into their positive or negative effects on the diversity and density of plant life. Soil properties vary with location, while geological, topographical, climatic, and hydrological conditions play a vital role in determining their physicochemical and biological attributes. Studying the soil characteristics of these internal wadi channels in the Wadi Al-Shati region is essential for identifying their potential as a sustainable natural resource. A scientific approach is necessary to improve, maintain, and conserve these soils, ensuring their long-term viability. This study aims to determine the physicochemical and biological characteristics of the soils within two internal wadi channels in Wadi Al-Shati, Libya: Wadi Tarut and Wadi Ququm. The results revealed significant differences in the soil properties of the two wadis. The percentage of organic matter in Wadi Tarut ranged from 1.2% to 2%, while in Wadi Ququm, it ranged from 1.3% to 2.8%. Similarly, particle density varied, measuring between 2.3 and 2.7 g/cm³ for Wadi Tarut and 2.3 and 2.8 g/cm³ for Wadi Ququm. Differences were also noted in water retention capacity, which ranged from 10.6% to 14% in Wadi Tarut and 9.4% to 15% in Wadi Ququm. Both wadis exhibited high electrical conductivity values, with Wadi Tarut soils ranging from 24.5 to 84.4 dS/m⁻¹ and Wadi Ququm soils from 4.20 to 10.60 dS/m⁻¹. The pH was nearly neutral in both wadis, ranging from 6.9 to 7.3 for Wadi Tarut and 7.2 to 7.6 for Wadi Qumqum. Sodium ion concentrations were elevated, ranging from 4.8 to 39.00 mg/L in Wadi Tarut and 14.6 to 36.00 mg/L in Wadi Qumqum. Potassium content in Wadi Tarut was between 3 and 35.2 mg/L, while in Wadi Qumqum, it ranged from 5.8 to 9.00 mg/L. The findings of this study lead to the conclusion that the environmental conditions of these two internal wadis, such as extreme aridity and high salinity, act as selective pressures, allowing only plant species capable of adapting to these harsh conditions to thrive.