Fundamentals of Soil Science (1+1)

Introduction

• The agricultural activities involve addition of nutrients, pesticides and sediment to soil.
• On the other hand, industry and urbanization pollute the soil with solid wastes, heavy metals, solvent and several other organic and inorganic substances.
• As the world population grows, increasing amounts of wastes are produced and most often soil is the medium for disposal of wastes.
• Dispersal of wastes from its source can be through the atmosphere, via the water bodies or directly in to the soil.
• Once in the soil it enters in to food chain thereby affecting plants, animals and human but in some cases, alters the composition of the soils and its ability to form perform its many functions. For example, some forms of pollutants can diminish the population of soil organisms such as earth worms and microbes, which decrease the biotic capabilities of the soil.
• The pollutant can be transported from the soil to water bodies where they contribute to further damage of environment.
• The soil acts as a physical filter by its sieving action , a chemical filter by absorption , precipitation and transformations of chemical substances, and a biological filter by decomposing organic materials, it does not have infinite capacity to perform these functions.
• The addition of any substance to soil which exert adverse effects on its functioning can be defined as soil contamination.

Types of environmental pollution activities :

• Two types of environmental pollution activities are associated with the soil.
• The pollution of soil itself making it unfit either as a medium for plant growth or for growing crops plants that do not contain enough toxic substances so as to suitable for human/ animal consumption. The indiscriminate application of nitrogen and some micronutrients can pollute the soil. An indiscriminate land application of wastes may often lead to pollution problems.
• Management of soil may contribute to the pollution of water such as leaching of nitrate to ground water.