Untitled Flashcards Set

Hydration of cations

Refers to how cations interact with water, influencing their effective radii and susceptibility to exchange in soil.

Effective radius

The size of a hydrated ion, which can affect its reactivity and exchangeability in soil.

Acid saturation

A measure of the amount of acidic cations in the soil, affecting its overall pH.

Justus von Liebig's Law of the Minimum

States that plant growth is limited by the most deficient nutrient, even if all other nutrients are adequate.

pH of soil

A measure of the acidity or alkalinity of soil, influencing nutrient availability and plant growth.

Aluminum toxicity

Occurs when Al3+ ions become available in acidic soils, competing with essential nutrients and potentially harming plant growth.

Liming

The practice of adding lime to soil to neutralize acidity and increase pH.

Sodic soil

Soil that contains high levels of sodium, leading to poor soil structure and reduced permeability.

Total Dissolved Solids (TDS)

A bulk measurement of all dissolved salts in water, often used to assess salinity.

Electrical conductivity (EC)

A measure of the soil's ability to conduct electricity, which increases with the concentration of dissolved salts.

Soil structure

The arrangement of soil particles and the pore spaces between them, influencing water movement and root growth.

Alkaline soil

Soil with a pH greater than 7, often found in arid regions with limited biological activity.

Salinity

The concentration of soluble salts in the soil, which can negatively impact plant growth.

Aluminum (Al3+)

A cation that can become toxic to plants at low pH levels, competing with vital nutrients.

Exchangeable Sodium Percentage (ESP)

A measure of the proportion of sodium in relation to other cations that affect soil sodicity.

Cation Exchange Capacity (CEC)

The ability of soil to hold and exchange positively charged ions, crucial for nutrient availability.

At soil pH levels below 6, crops will experience growth-limiting levels of potassium availability.  True or false

False

The best descriptor of aluminum toxicity is:

an increasing solubility of aluminum in low pH soils interferes with nutrient cation retention in CEC

Alkaline soils:

could be calcareous soils

Sodic soils (choose the best answer):

can be identified from their ESP or SAR

Salts entering the root zone in saline soils occurs through

additions of slightly saline irrigation water, or upward movement of saline groundwater

Sodium interferes with soil structure because

it creates a thick ionic swarm between soil colloids, interfering with their ability to attach to each other

Reclamation of sodic soils focuses on:

replacing sodium with calcium in exchange matrix, while creating a soluble salt that can be leached away

Alkaline soils are more common in humid regions because:

n/a, alkaline soils are more common in arid regions