Backyard Aquaponics
A place to discuss aquaponics

i know some of the folks here will find this interesting, this tool shows the amount and cost/lb unit of N, P and K in different livestock manure;
http://aede.osu.edu/Programs/FarmManagement/Programs/N_P_K%20breakdown.xls

and a "companion" tool, OSU's manure rate calculater, allows you to select different inputs and gives you the manure rate calc (ohio state u developed it)
http://aede.osu.edu/Programs/FarmManagement/Programs/OSU_manure_rate_calculator_locked.xls