chapter_4c_-_pH_v3_-_HANDOUT

Soil pH

A measure of the acidity or alkalinity of soil, indicating the concentration of hydrogen ions in the soil solution.

pH scale

A logarithmic scale that measures the acidity or alkalinity of a solution, ranging from 0 (most acidic) to 14 (most alkaline).

Active acidity

The acidity in the soil solution, determined by pH.

Reserve acidity

Acidity due to hydrogen ions and aluminum ions in the solid phase of the soil.

Buffering capacity

The ability of soil to resist changes in pH when acids or bases are added.

Microbial activity

The activity of microorganisms in the soil, which can be affected by soil pH.

Aluminum toxicity

A condition where aluminum becomes toxic to plants, frequently occurring in acidic soils.

Sodicity

A condition where a significant percentage of the exchangeable cation sites in soil are occupied by sodium ions.

Salinity

The amount of salts accumulated in the soil, affecting plant water absorption.

Leaching

The process of removing excess salts from the soil by using irrigation water.

Hydrolysis

A chemical process that involves the reaction of water with soil minerals to form acids.

Organic matter (OM) content

The amount of decomposed plant and animal material present in the soil, influencing its properties.

Calcium carbonate (CaCO3)

A compound used to neutralize soil acidity; commonly referred to as lime.

Electrical conductivity (EC)

A measure of the ability of an electrolytic solution to conduct electric current, indicating the ionic concentration.

Nitric acid (HNO3)

An acid formed from the reaction of nitrogen oxides with water, contributing to soil acidity.

Sulfuric acid (H2SO4)

An acid that can be deposited in soils through natural processes or human activity.

Humic acids

Organic compounds derived from decaying plant material, contributing to soil fertility.

pH meter

An electronic device used to determine the pH of a solution accurately.

Acid-tolerant crops

Plants that can grow in acidic soil conditions, such as sweet potato and coffee.