Effects of deforestation on soil erosion in Nigeria

Deforestation in Nigeria can be said to be the process of cutting down trees or clearing forests for either agricultural, commercial, residential, or industrial purposes.^[1] In Nigeria, it has become an increasingly important environmental concern as it has adverse effects on the ecosystem, including soil erosion.^[2][3]

Soil erosion

Soil erosion is the process by which soil particles are displaced and transported from one location to another, leaving the underlying soil exposed and vulnerable to further erosion.^[4] Soil erosion is the result of natural physical forces, such as water and wind, gradually wearing away the topsoil in a field.^[5] This process can be slow and inconspicuous or occur rapidly, leading to significant topsoil loss.^[5] Apart from soil erosion, there are other severe soil degradation issues, including soil compaction, reduced organic matter, loss of soil structure, inadequate internal drainage, salinization, and soil acidity problems.^[5] Soil erosion, along with its consequences for humanity, presents a formidable challenge that jeopardizes both people and the socio-economic progress of their surroundings. Addressing and mitigating the impacts of this phenomenon necessitate immediate, swift, and pressing action to pave the way for sustainable development.^[6]

Effects of deforestation on soil erosion

Deforestation has numerous impacts on soil erosion, including:

• Loss of vegetation cover: When trees are cut down, the vegetation cover that protects the soil from flooding wind, and other erosive forces is lost.^[7] This exposes the soil to the atmospheric elements and makes it more susceptible to erosion.^[8]
• Reduced soil organic matter: Trees and other vegetation contribute to the buildup of organic matter in the soil. When these plants are removed, the organic matter content of the soil decreases, making it less able to hold water and more susceptible to erosion.^[9] It is more difficult to raise or maintain levels of biological activity and soil organic matter when human activity is present. It takes consistent work to maintain soil organic matter, including crop rotation and the return of organic resources. Due to quick decomposition, well-aerated soils and warm, humid climates present special challenges. In cold temperate and moist-wet environments, fine-textured soils can sustain organic matter levels with less residue. Tillage and burning are examples of management techniques that can harm soil organisms, resulting in erosion and the loss of organic matter.^[10]
• Increased runoff: Deforestation leads to an increase in runoff, as water is no longer absorbed by the vegetation and instead runs off the surface of the soil.^[11] This increases the erosive power of the water and can lead to the formation of gullies and other erosive features.
• Soil compaction: Deforestation can also lead to soil compaction, as heavy machinery is often used to clear the land.^[12] Compacted soil is less able to absorb water and is more susceptible to erosion. Compaction of the soil is an essential feature of building because it reduces the air spaces between soil particles, densifying the soil. Because of this, the soils become more compacted and have a larger unit weight, which is necessary for a sturdy working platform. To improve soil density and bearing strength, compaction tools such rammers, pneumatic rollers, padfoot and tamping foot rollers, and smooth rollers are utilized.^[13] While padfoot and tamping foot rollers disrupt the natural links between particles for greater compaction, smooth rollers use static pressure, vibration, and impact to compact soil. While rammers are lightweight and portable for tight spaces, pneumatic rollers employ staggered rubber tires with variable air pressure for small to medium-sized soil compaction projects.^[13] Depending on the kind of soil being compacted, the appropriate compaction equipment must be used. While coarse-grained soils are granular and cohesive, organic soils are not appropriate for compaction or construction. An important factor in determining the ultimate level of compaction is the equipment selection for a certain type of soil. Because it gives the project a solid functional foundation, soil compaction is an essential step in the construction process. For structural elements like slabs, footings, and foundations, it is imperative to enhance the bearing capacity and stiffness of in-situ (natural state) soil. By rupturing the innate linkages between fine-grained soil particles, padfoot and tamping foot rollers can compact soils with higher cohesive contents. With their staggered rubber tires and variable air pressure, pneumatic rollers are an effective tool for small to medium-sized soil compaction tasks. Particularly for cramped workspaces or tiny locations, tamping rammers are lightweight and portable. Puddles in yards, settling cracks in foundations, and bowing sidewalks are all examples of the detrimental effects of inadequate or incorrect soil compaction. Early soil compacting during construction reduces these impacts and guarantees a sturdy working platform. There are several possibilities for soil compaction equipment, each having advantages of their own.^[13]
• Loss of biodiversity: Deforestation also leads to a loss of biodiversity, which can have indirect effects on soil erosion. Biodiverse ecosystems are more resilient to environmental stresses, including erosion, and the loss of species can make ecosystems more vulnerable to erosion. Ecologically and economically, biodiversity loss is substantial, especially for species whose populations are declining. A species' long-term existence is threatened by the loss of genes and individuals because fewer partners become available and the likelihood of inbreeding increases when closely related survivors mate. A declining biodiversity lowers the complexity, productivity, and quality of services provided by an ecosystem. The ecology can become unstable and collapse if it loses its ability to bounce back from disruptions. "Ecosystem homogenization" throughout the globe and across areas is another effect of decreased biodiversity. While generalist species and species that people like become important roles in ecosystems vacated by specialist species, specialist species are frequently the most vulnerable to population decreases and extinctison when conditions change. Each ecosystem loses some of its complexity and uniqueness as a result. Common food crops like Cavendish bananas, which are susceptible to Tropical Race (TR) 4, a fusarium wilt fungus that obstructs the flow of water and nutrients, have more obvious economic and societal repercussions. Since 1900, an excessive reliance on crop varieties with high yields has led to the extinction of around 75% of food crops. Lost species indicate missed chances to treat and eradicate illnesses like Chagas disease and malaria. In order to combat biodiversity loss, a combination of economic and governmental policies, as well as ongoing research and outreach, are required. To encourage the preservation of natural environments and shield species inside them from needless harvesting, governments, nongovernmental organizations, and the scientific community must collaborate. Other crucial aspects are sustainable development, legislation against poaching and the indiscriminate trade in wildlife, and port inspections of shipping cargo.^[14] Governmental cooperation, safeguarding surviving species from overfishing and poaching, and preserving their habitats and ecosystems are all essential to halting the loss of biodiversity.^[14]

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