Effective temperatures
This is the accumulation of air temperatures above a specific biological base threshold required for a crop to complete a developmental stage.
Также говорят: growing degree days, GDD, accumulated thermal units
This metric allows agronomists to predict crop phenology, estimate harvest dates, and select appropriate varieties for specific climatic zones. By tracking these values, farmers can optimize the timing of irrigation, fertilization, and pest control applications based on actual crop progress.
The calculation involves subtracting the biological base temperature—specific to each crop—from the daily average temperature. Consistency is key when collecting data throughout the growing season to ensure accurate predictions of plant development stages.
A common pitfall is ignoring extreme heat or drought stress, which can cause plants to reach physiological maturity faster or stall growth despite reaching the expected thermal units. It is essential to integrate these calculations with soil moisture data and variety-specific heat requirements to avoid significant errors in crop management.