humic acid

American  

noun

1. a brown, melanin-tinted mixture of polymers, found in lignite, peat, and soils, where it acts as a cation exchange agent: used in drilling fluids and inks.

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Etymology

Origin of humic acid

First recorded in 1835–45

Example Sentences

Organic-rich soils seem particularly problematic; they are ripe with molecules like humic acid, which behaves like DNA and can foul later sequencing.

From Science Magazine • Dec. 10, 2019

Lignite coal is the main raw material for Yongye’s humic acid products, according to filings.

From BusinessWeek • Jun. 22, 2011

The purchase of the humic acid supplier opened access to raw materials, said Yu.

From BusinessWeek • Jun. 22, 2011

I suppose you will reply, By combining with oxygen and forming humic acid.

From Essays in Natural History and Agriculture by Garnett, Thomas

Both the humic acid and humin are mixtures, and several constituents have been separated; ulmic acid and ulmin, in addition to humic acid and humin, are perhaps the best characterized.

From Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 8 "Hudson River" to "Hurstmonceaux" by Various