> For the complete documentation index, see [llms.txt](https://swatplus.gitbook.io/io-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://swatplus.gitbook.io/io-docs/theoretical-documentation/section-5-land-cover-plant/actual-growth/actual-yield.md).

# 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.