Introduction

The hourly time step version of WARM accounts for temperature effect on crop growth and development in each hour during the day.

Crop development is simulated starting from the accumulation of growing degrees on hourly bases (Equation 1):

where Topt and Tb represent the optimum and base temperatures for development, respectively. Their difference is equal to the maximum number of growing degrees that can be accumulated for crop development during a day; the denominator allows to estimate the maximum number of growing degrees in a hour. A beta function (i.e., f(T), Equation 2; Yin et al., 1995) is used to infere the actual number of growing degrees-hour (GDH) accumulated, accounting for thermal limitations:

where Tmax, Topt and Tb represent the cardinal temperatures for development.

The same equation (with Tmax, Topt and Tb representing the cardinal temperatures for growth) is used to estimate the hourly temperature limitation factor to photosynthesis (Equation 3, see WARM growth for explanation).

Created with the Personal Edition of HelpNDoc: iPhone web sites made easy