> 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/introduction-1/channels/nutrients.cha/const_p.md).

# const\_p

The Michaelis-Menton half-saturation constant for P defines the concentration of phosphorus, at which algal growth is limited to 50% of the maximum growth rate.