In soil science, water in the soil that plants can access and use for growth.
From Latin 'chrestus' (useful) and Arabic 'ard' (earth/soil). A technical term created in the 19th century for soil water available to plant roots.
Soil scientists borrowed 'chrestus' (useful) to describe the 'useful water' versus the unusable water in soil—a perfect example of technical jargon precisely capturing something essential that laypeople never think about.
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