It only exists naturally on earth in very small amounts and its short half-life means useful quantities have to be produced synthetically.
Phosphorus-32 finds use for analysing metabolic pathways in pulse chase experiments, where a culture of cells is treated for a short time with a phosphorus-32-containing substrate.
The sequence of chemical changes, which happen to the substrate, can then be traced by detecting which molecules contain the phosphorus-32 at multiple time points following the initial treatment.
The phosphorus-32-labelled fertiliser is given to the plant hydroponically, or via water in the soil, and the usage of the phosphorus can be mapped from the emitted beta radiation.
Typical safety precautions when working with phosphorus-32 include wearing a personal dosimeter to monitor exposure and an acrylic or perspex radiation shield to protect the body.
Because the beta radiation from phosphorus-32 is blocked by around 1 m of air, it is also advisable to wear dosimeters on the parts of the body, for example the fingers, which come into close contact with the phosphorus-32-containing sample.