Definition

Noun: A black, complex organic substance that is part of the humus fraction and is insoluble in water. It is formed during the decomposition of plant and animal matter in soil.

Usage

Humin is a technical term used primarily in soil science, geology, and environmental chemistry. It refers to the most stable and insoluble component of soil organic matter. It is not used in everyday conversation.

Examples

• The dark color of this fertile soil is largely due to the presence of humin.
• In the laboratory, they separated the humic acids from the humin fraction of the peat sample.
• The study focused on the carbon sequestration potential of humin in agricultural soils.

Advanced Usage

• "Humin fraction": This is a common collocation referring to the portion of soil organic matter identified as humin.
  • The recalcitrant humin fraction contributes to long-term carbon storage in ecosystems.

Variants and Related Words

• Humic (adjective): Relating to or consisting of humus.
  • Humic substances are vital for soil health.
• Humus (noun): The dark organic material in soil, formed by the decomposition of leaves and other plant material.
  • Compost adds valuable humus to the garden bed.

Synonyms

• Soil organic matter (broader term)
• Recalcitrant organic carbon (functional description)

Notes on Meaning

This word has a single, specific scientific meaning. It does not have different everyday meanings, idioms, or phrasal verbs.

Noun

1. a black humic substance that is not soluble in water