Crop emergence

Crop emergence can be defined as a function of the effective daily temperature sum since sowing date.

It is based on the thermal time accumulated between a base temperature and a maximum temperature.

Growing degree days rate is calculated according to the following equations:

where GDDrate is growing degree days rate (°C-days), Tavg is average daily air temperature (°C), Tbase is base temperature for emergence (°C) and Tmax is maximum temperature for emergence (°C).

Then, the sum of growing degree days is calculated:

where GDDsum(t) is the sum of growing degree days at time t (°C-days) , GDDsum(t-1) is the sum of growing degree days at time t-1 (°C-days), GDDrate is growing degree days rate (°C-days).

Then, the degree-days are converted into a decimal code (assuming values from 0.00=planting to 1.00=emergence). Decimal code is obtained with the following equation:

where DVS is development stage code of emergence phase (unitless), GDDsum is the sum of growing degree days (°C-days) and GDDem are growing degree days from sowing to emergence (°C-days).

Created with the Personal Edition of HelpNDoc: Easily create Web Help sites