This section is from the book "Commercial Gardening Vol1", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
Besides bones, superphosphate, and basic slag, other manures are also valuable for the amount of phosphates they contain. Wood ashes, i.e. the burnt refuse from weeds and plants of all sorts, contain from 100 to 145 lb. of phosphates in every ton, and even a larger supply of potash - 135 to 224 lb. in every ton.
Guanos - both Peruvian and fish - also contain large quantities of phosphates, Peruvian guano having from 350 to 400 lb. in every ton, and fish guano from 200 to 300 lb. Farmyard and stable manure, seaweed, sewage sludge, soot, night soil, pigeon, poultry, and all animal excreta contain supplies of phosphates as well as nitrates and potash.