Soil Colloids and Nutrient Exchange

These flashcards cover essential vocabulary related to soil colloids, their properties, importance in nutrient exchange, and overall soil fertility.

Soil Colloids

Particles in the soil with diameters less than 0.001 mm, mainly composed of clay and humus.

Properties of Colloids

Colloids possess a huge surface area and have negative electrical charges on their surfaces.

Cation Exchange Capacity (CEC)

The ability of soil to adsorb and exchange cation nutrients, measured in milliequivalents per 100 grams of soil.

Macronutrients

Plant nutrients used in larger amounts, including nitrogen (N), phosphorus (P), potassium (K), sulfur (S), calcium (Ca), and magnesium (Mg).

Cation Exchange

The process by which adsorbed ions are exchanged into the soil solution, allowing plants to absorb nutrients.

Dynamic Equilibrium

A natural chemical process maintaining a balance between cations on adsorption sites and cations in soil water.

Anion Mobility

Anions (-) remain mobile in soil water and diffuse quickly to plant roots, but are prone to leaching.

Exchange Complex

The zone of water surrounding colloids where cation exchange occurs, comprising negatively charged surfaces and a layer of adsorbed cations.

Estimating CEC

Approximate CEC can be calculated based on clay and organic matter content, influencing soil fertility.

Effect of Colloids on Nutrient Availability

Colloids act as storehouses for nutrients, regulating cation supply and preventing leaching, while anion nutrients are less retained.