Actual Yield

The harvest index predicted with equation 5:2.4.1 is affected by water deficit using the relationship:

$HI_{act}=(HI-HI_{min})*\frac{\gamma _{wu}}{\gamma _{wu}+exp[6.13-0.883*\gamma _{wu}]}+HI_{min}$ 5:3.3.1

where $HI_{act}$ is the actual harvest index, $HI$ is the potential harvest index on the day of harvest calculated with equation 5:2.4.1, $HI_{min}$ is the harvest index for the plant in drought conditions and represents the minimum harvest index allowed for the plant, and $\gamma _{wu}$ is the water deficiency factor. The water deficiency factor is calculated:

$\gamma_{wu}=100*\frac{\sum^m_{i=1} E_a}{\sum ^m_{i=1} E_o}$ 5:3.3.2

where $E_a$ is the actual evapotranspiration on a given day, $E_o$ is the potential evapotranspiration on a given day, $i$ is a day in the plant growing season, and $m$ is the day of harvest if the plant is harvested before it reaches maturity or the last day of the growing season if the plant is harvested after it reaches maturity.