Water and Soil

The field of study that deals with water’s chemical and physical properties and their details and reasonings, is known as water chemistry. The inherent chemical composition of the soil is referred to as soil chemistry. Also, the parent material of a soil determines the natural chemical composition of that soil. This study material notes on water and soil will help you understand their properties better.

Definition of water and soil

Water: H2O, or water, is a material made up of the chemical elements hydrogen (H2) and oxygen (O2). Water is a colourless, tasteless, and odourless liquid because it is a polar inorganic substance. In fact, it is recognised as the universal solvent since it is the most researched chemical compound. It’s the only substance that can be found in all three forms of matter: solid, liquid, and gas. Soil: Soil is the top layer of the earth. It comprises inorganic particles and natural matter. Soil offers support to plants and is likewise their source of nutrients and water.

Formation of a water molecule

The chemical bond between hydrogen and oxygen forms a water molecule. In fact, it is the chemical bond in which electrons are distributed unequally among the atoms. Every water molecule forms a covalent bond with two hydrogen atoms and one oxygen atom, resulting in the following reaction:

H₂ + O₂ → H₂O

What are the different types of water states?

Water is the only substance that can exist in all three phases of matter – solid, liquid, and gas – as previously stated. Ice is the first solid condition of the water. Water exists as a solid-state substance in two forms: ice, which is a hard, amalgamated crystal, and snow, which is a loosely amalgamated crystal. The liquid state of water, also known as “water,” is the most typically seen water condition in the Earth’s atmosphere. Water vapour, or steam, is the third state of water in its gaseous state.

What’s the connection between the Hydrological Cycle and Water Levels?

A hydrological cycle is a natural cycle in which water flow is regulated in various states of water, allowing all life forms on earth to use it. This is bolstered by the fact that water is readily available in all states. Furthermore, the evaporation, precipitation, and condensation processes make it easier to move water across various landforms.

Physical Properties of water

• Water is a colourless, odourless, and tasteless liquid in its natural condition. It has a hexagonal crystal shape

• The boiling point of water is described as the temperature at which the liquid’s vapour pressure equals the pressure around the liquid, causing the liquid to turn to vapour. The boiling point of water is 100°C, as we all know

• The freezing point is the temperature at which a substance transitions from a liquid to a solid state. The freezing point of water, which is 0°C or 32°F, is the point at which liquid state water transforms to solid-state ice

• At 25 degrees Celsius, water has a high specific heat capacity of 4.2 joules per gram. The extensive hydrogen bonding between the water molecules accounts for this

• Water Density: Water has a density of around 1 gm/cc and fluctuates in an unusual pattern with temperature

• The viscosity of water is determined by its resistance to deformation at a particular rate. Water has a viscosity of 0.89 cP. (centipoise)

•  Water has a dielectric constant of 78.6, which is unusually high. Because water is a universal solvent, this constant is extremely important

Water’s Chemical Properties

• One of the essential aspects of water is its amphoteric tendency. The ability of a chemical to operate as an acid or base is referred to as amphoteric

•  Water is neither acidic nor basic in its natural form. The ability to donate and accept protons is the reason for this

• Rainwater, on the other hand, is mildly acidic, with a pH of 5.2 to 5.8

Physical Properties of Soil

Horizonation

A soil profile is made up of separate strata called “horizons.” They are usually perpendicular to the ground.

Colour of the Soil

• The brown, yellow, and red colours you observe in well-aerated soils are caused by oxidised or ferric (Fe³⁺) iron complexes

• When iron is converted to a ferrous (Fe²⁺) state, it becomes mobile, allowing it to be removed from certain soil locations. When the iron is eliminated, the remaining colour is grey, or the reduced iron colour is green or blue

• Reduced iron can be reoxidised and redeposited after aeration, sometimes in the same horizon, resulting in a mottled or variegated colour pattern

The texture of the Soil

The proportion of soil “separates” that form the mineral component of soil is referred to as soil texture. Sand, silt, and clay are the three types of separates. The following size ranges are available in these soil separates:

• Sand = <2 to 0.05 mm

• Silt = 0.05 to 0.002 mm

• Clay = <0.002 mm

Structure of the Soil

The soil fragments can be collected into discrete structural elements known as “peds.” Soil structure refers to how these peds are grouped into a repeating pattern. Cracks called “pores” run between the peds, allowing soil air and water to pass through. The shape of the individual peds that occur inside a soil horizon is the most typical way to define soil structure.

Chemical Properties of Soil

a. Cation Exchange Capacity– In the soil environment, some plant nutrients and metals reside as positively charged ions, or “cations.” Hydrogen (H+), aluminium (Al³⁺), calcium (Ca²⁺), magnesium (Mg²⁺), and potassium (K⁺) are some of the most frequent cations found in soils.

b. Soil pH– Ion solubility, which impacts microbial and plant growth, is the most important effect of pH in the soil. For most crops, a pH range of 6.0 to 6.8 is appropriate since it corresponds to the optimum solubility of the most critical plant nutrients. At lower pH, several minor elements (such as iron) and most heavy metals are more soluble. As a result, pH regulation is critical for regulating heavy metal mobility (and potential groundwater contamination) in soil.

Conclusion

Many chemical reactions involving water are directly involved in the construction and breakdown of essential cell components. Photosynthesis, the process in which plants produce sugars for all living things, necessitates the presence of water. As a result, water chemistry aids in a better understanding of all water-related activities. The chemistry of the soil is a critical characteristic since it determines what will grow and how well it will develop. Knowing water and soil chemistry helps to understand the complex phenomenon that involves water and soil.