Thermal time accumulation
nounPronunciation: /ˈθɜːrməl taɪm ækˌjuːmjəˈleɪʃən/
The cumulative heat units (degree-days) accumulated by plants above a base temperature threshold required for completing developmental stages under variable temperature conditions. This concept allows prediction of phenological events across different environments and is essential for understanding heat stress impacts on crop development.
Plain English
Measuring how much heat plants absorb to complete growth stages, accounting for varying daily temperatures.
Etymology & History
Usage
"Climate change shifts thermal time accumulation patterns, causing wheat flowering to occur earlier in many growing regions."
Style guide notes: Always specify the base temperature and degree-day units (°C or °F) when reporting thermal time values.
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Related Terms
Frequently Asked Questions
How is thermal time calculated?
Daily thermal time = daily mean temperature minus base temperature; cumulative values across season predict developmental stages.
Why does thermal time matter for crop management?
It predicts flowering and maturity timing regardless of calendar date, improving irrigation and harvest scheduling decisions.
Why Test Candidates on This?
Fundamental concept in crop modeling, climate impact assessment, and breeding program selection of maturity groups.
Required skill level: Mid