> 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-growth.md).

# Actual Growth

                        The plant growth factor quantifies the fraction of potential growth achieved on a given day and is calculated:

              $$\gamma\_{reg}=1-max(wstrs,tstrs,nstrs,pstrs)$$                                                   5:3.2.3

where $$\gamma\_{reg}$$ is the plant growth factor (0.0-1.0), $$wstrs$$ is the water stress for a given day, $$tstrs$$ is the temperature stress for a given day expressed as a fraction of optimal plant growth, $$nstrs$$ is the nitrogen stress for a given day, and $$pstrs$$ is the phosphorus stress for a given day.

                The potential biomass predicted with equation 5:2.1.2 is adjusted daily if one of the four plant stress factors is greater than 0.0 using the equation:

             $$\Delta bio\_{act}=\Delta bio\*\gamma\_{reg}$$                                                                                           5:3.2.1

          where $$\Delta bio\_{act}$$ is the actual increase in total plant biomass on a given day (kg/ha), $$\Delta bio$$ is the potential increase in total plant biomass on a given day (kg/ha), and $$\gamma\_{reg}$$ is the plant growth factor (0.0-1.0). 

        The potential leaf area added on a given day is also adjusted daily for plant stress:

                  $$\Delta LAI \_{act,i}=\Delta LAI\_i\*\sqrt{\gamma \_{reg}}$$                                                                          5:3.2.2

           where $$\Delta LAI \_{act,i}$$ is the actual leaf area added on day $$i, \Delta LAI\_i$$ is the potential leaf area added on day $$i$$ that is calculated with equation 5:2.1.16 or 5:2.1.17, and $$\gamma \_{reg}$$ is the plant growth factor (0.0-1.0).