Soil definition isin different ways over time.
However, all these definitions have lostsimilarities which entirely give the Soil a compound nature and structure.According to Merriam Webster dictionary, Soil is defined as the upper part ofthe earth that is used in planting and ploughing. According to Soil ScienceSociety of America from soil science glossary, Soil is a mineral or organicmaterial which is unconsolidated on the upper or immediate surface of theearth. It acts as the underlying natural channel through which plants grownaturally and human plough or cultivates on. On the other hand, Soil Taxonomydefines Soil as a physical body that is comprised of organic matter andminerals, gases and liquids on the earth surface. The soil is the result of aprocess of additions, losses, transfers, and transformations of matter andenergy in the natural environment giving it the ability to support the growthof plants. Thesoil has got specific characters classified as layers or horizons that are identifiableupon the transformations of the initial materials.
According to soil taxonomyfindings, the ground has reached two levels, the upper and the lower limits.The boundary between the air and soil, water, or any decomposed plant materialscover the upper limit of Soil. Areas permanently covered by water are notconsidered to have soil for it may not support growth or root of plants. Thenon-soil part that separates the soil underneath it’s not easy to define sinceit is more of rocks that cannot support plant rooting, human survival or anyother biological activities for both plant and human existence. The soil consists of layers on the earthsurface that have been formed through climatic changes, relief, and decompositionof living organisms over time. (Agriculture, 2017) Severalprocesses are involved in the soil formations. The parent material in the soilformation is said to be the Rock. Rocks may be either beneath the soil or awaybut due to the flow of winds, water glacier erosions or transportation, theSoil is formed.
Paedogenesis is the process through which Soil is formed, andclimatic conditions are one factor that directly affects the rate of parentmaterial weathering and formation of the Soil. There are four fundamentalprocesses involved in Soil formation namely, parent material weathering, Soildevelopment in a significant way, structural distinguishing of the developedsoil into layers or horizons and the translocation of the developed Soil. Thereseveral ways in which Soil is trans-located and through these movements, areaswhere parent material may not have been there getting developed Soil. Thismeans that Soil can be transported several miles away from its originalformation point through glacier movement, water flow, and even wind. Example ofglacier soil translocation is recorded in the UK where the glacier pushed soilin the southwards down the hills several miles away from its original point offormation. Due to climate change, glacier melted, and heaps of Soil was leftbehind forming great moraines which are tourist scenes. Moraines are realdemonstrations of soil translocations through glacier flow. Fig.
1. Picture ofmoraines formed after melting of the glacier in UK. Water is another cause of soiltranslocation. Through running waters in rivers, soil particles are washed andcarried away. Weighty soil particles like sand are quickly deposited and leftand the other light particles carried as far as the water mass can withhold theweight. Soils deposited through river flow have different names based on thedeposit destinations. Lacustrine are soil deposits on lakes side, riverine aresoil deposits by rivers, and marine alluvial are soil deposits by sea. Otherthan river, lake and sea waters, rainfall is also another significant factor intranslocation of soil.
All exposed land is washed away through erosions whichare categorized differently depending on the status of the landscape and thetype of rainfall. Soiltranslocations can also happen through the wind. In desert areas, extreme windcauses severe translocation of soil from one location to another. The quantityof soil particles transported through wind depends on the topography,landscape, and environmental occupation. If the land is filled withplantations, transportation through wind may not be that effective due tobarriers of the land cover. Soil deposited trough wind is called Eolian, andthat of gravity is colluvial. (Soil-net.com, 2017) Itis therefore clear that Soil is formed from rocks through continuous weatheringof the rocks, the parent materials.
Rocks consist of minerals mixed to formstones. There are three categories of these rocks, the igneous, metamorphic andsedimentary rocks. Igneous contains base minerals and are developed throughfluid magma flow.
Deposition of weathered materials forms the sedimentary rocksthrough cemented weathered elements. Metamorphic are comprised of the other twotypes of rocks, the sedimentary and igneous, which are formed through excessivepressure and temperature. These rocks are the primary parent materials in theSoils formation. Accordingto several types of research conducted across the world by different scientist,it quite evident that soil is a non-renewable resource. This conclusion isarrived based on the time taken in the soil natural formation process which isnot even within a human lifespan.
Based on this factor, several agenciespromote soil conservation. About 33 percent of the land is under danger ofdegeneration through soil erosion chemical pollution, acidification and alsosalinization. This is based on the findings captured on the 2015 internationalyear of soils campaign flagged, healthy soils for healthy life sponsored byFood and Agriculture Organization (FAO). (FAO, 2015) Otherthan Soil degradation through erosion and chemical pollution, other factors areaffecting the Soil like urbanization, deforestation, the rapid growth of worldpopulation hence excessive land usage. There are several ways to control Soildegradation including the involvement of the government in establishingmitigation plans to manage climate change, management policies and promotion ofbest environmental management practices.
