Fertillisers are NOT phosphorus pentoxide, P2O5, P2O5, phosphoric acid anhydride, is hygroscopic as hell, its used as a drying agent for extracting the very last bits of water from a sample, fertillisers commonly list P content as P2O5, for some wierd reason for calculations of totals and stuff. I made the same mistake a few times when I was just starting out with hobby chemistry.
Phosphate requires a large amound of heat to be reduced, mixing calcium phosphate fertillizer with an equal amount of charcoal, and heating to a high temperature, a couple of K degrees as i recall, can be done with a coal furnace.
Have a look on www.sciencemadness.org
because they have an extended thread running on obtaining elemental phosphorus.
Small amounts of WP can be distilled from the striking strips of safety match books, which use red P as a striking surface, use MEK to liquify the casein glue that holds the RP on the box, then hydrolyse the casein with HCl.
Heat the RP thus collected in a SEALED testtube or boiling tube, in my experience removing the air, or using inert gases isn't nescessary, as the very first WP formed uses up all the oxygen present.
Remember, white phosphorus is extremely toxic, causing very severe burns, it is pyrophoric, a small chunk will often autoignite in air, allthough I have had pieces that were left out, and merely smoked, only igniting when touched with a hot wire or a lighter flame.
An approximate human lethal dosage of white phosphorus is around 50mg, whilst the red allotropes are a great deal safer, being non pyrophoric, yet remaining highly flammable, and losing a great deal of WP's toxicity. Red P is safe to handle, so long as it is responsibly treated, while WP just likes to bite one on the ass
I have made some tracers myself, for an air rifle that worked quite well, although protecting the WP from air until firing is difficult.
If you make your own bullets, something you might like to try is ones made of sodium or potassium metal, you will need to make your bullet, then coat it in a thin film of water soluble plastic, such as PVA dissolved in a non-aqeous solvent to protect it from air. The alkali metals will fizz and explode on striking a damp target/would be burglar
Rubidium metal would also work. Be careful in handling the metals, touch only with gloves, and remember they are pyrophoric as hell and like to explode