Readily available source of Nitrogen Nitrates?

[wallywonks]

if I cook 6-6-0 Shrimp Meal in soil for 4 weeks and Shrimp Meal is 100% readily available in soil in 0 to 1 month does the Nitrogen and Phosphorus stay in the soil?

I've heard of Nitrogen fixing and I don't remember if it's an amendment or something else so Nitrogen doesn't escape. I also don't water to runoff with my organic soil.

I read Nitrates are the best Nitrogen and Urea and Ammonium is not good for plants especially Ammonium. Urea takes longer to convert to Nitrate.

So EWC have lots of Nitrates. I don't know about Rabbit manure what type of N it's made up of. Maybe both Nitrates and Urea from Alfalfa feed and Rabbit urine.

Any thoughts? Just trying to figure out N for autos short Veg stage.