Dear DSSAT users,
I have a small doubt on the unit of one of the genotype parameters (in
the ecotype file of Maize): "GDDE" = thermal time from planting to
emergence / cm seed depth.
Working on Zambian data, I was able to calculate the degree days from
planting to emergence for 6 years: median value = 135 °C.days.
According to the staff in the field, the seed depth is 2 or 3 cm.
Therefore, GDDE should be between 45 and 67, but there is a problem of a
factor 10. Indeed, the fit is excellent when GDDE is between 5 and 7.
So, is the unit of GDDE "°C.days /mm" instead of "°C.days /cm"? Or did I
misunterstand something?

I am aware of the limited importance of such an interrogation...
Regards,

Guillaume C.

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Guillaume CHIRAT
Docteur - Ingénieur Agro
CIRAD
Systèmes de cultures annuelles
CA2AFRICA project
(+33)4 67 61 56 91