Bone meal is a mixture of finely and coarsely ground animal bones and slaughter-house waste products. It is used as an organic fertilizer for plants and as a nutritional supplement for animals. As a slow-release fertilizer, bone meal is primarily used as a source of phosphorus and protein. Finely ground bone meal may provide a quicker release of nutrients than the coarser ground version of bone meal.
Legally, in the United States, for something to be classified as a fertilizer, it has to be a soil amendment that guarantees the minimum percentages of nutrients, primarily nitrogen, phosphorus, and potash. For a fertilizer to be considered "organic," it has to be derived from natural sources.
Bone meal once was often used as a human dietary calcium supplement. Research in the 1980s found that many bone meal preparations were contaminated with lead and other toxic metals, and is no longer recommended as a calcium source.
Bone meal, along with a variety of other meals, especially meat meal, is used as a dietary/mineral supplement for livestock. It is used to feed monogastric animals with bone meal from ruminants, and vice versa, to prevent the spread of bovine spongiform encephalopathy (BSE) or "mad cow disease". Proper heat control can reduce salmonella contaminants.
As a fertilizer, the N-P-K (Nitrogen-Phosphorus-Potassium) ratio of bone meal is generally 4-12-0, though some steamed bone meals have N-P-Ks of 1-13-0. Bone meal is also an excellent source of calcium, but does not provide enough nitrogen to be beneficial to plants. Plants can only get phosphorus from bone meal if the soil pH is below 7.0 (acidic soil), according to recent Colorado State University research.
Organic fertilizers usually require the use of a variety of fungi in the soil to make the nutrients in the fertilizer bioavailable to the plant. For plants needing phosphorus, the fungi mycorrhiza penetrate the root break down the compounds containing the phosphorus for easier absorption and utilization, and in turn the plants supply the mycorrhizae with amino acids and sugars.
In the 1980s, bone meal was identified as a vector for bovine spongiform encephalopathy (BSE, or "mad cow disease") among livestock. Bone meal produced in the 1970s from the corpses of sheep bearing scrapie may have caused BSE in cattle when it was fed to them, but the pathogen very rarely crosses species, so it is more likely to have spread from cattle bone meal. The type of processing can determine if the infectious agent would be passed on. Proper heat treatment can reduce the chance of salmonella being transferred to any other livestock.
- Brigham and Women's Hospital. "Bone Meal". Retrieved 22 November 2012.
- Card, Adrian; David Whiting; Carl Wilson; Jean Reeders (December 2011). "Organic Fertilizers" (PDF). Colorado State University Extension. Colorado Master Gardener Program (CMG Garden Notes): 4. Retrieved 8 October 2014.
- Animal Feed Resources Information System, University of Kentucky, College of Agriculture, Poultry Extension. "Common Protein Sources for Poultry Diets". Retrieved 23 November 2012.
- Arakaki, Alton S. of Bone Meal Soil Amendment on Corn and Bean Seedlings.pdf "Response to Corn and Bean Seedlings to Preplant Application of Island Commodities" (PDF). Retrieved 22 November 2012.
- Chen, L.; J. Helenius; A. Kangus (2009). "NJF Seminar 422: Meat bone meal as nitrogen and phosphorus fertilizer (abstract)" (PDF). Nordic Association of Agricultural Scientists 5 (2): P. 26. Retrieved 23 November 2012.
- Stern's Introductory Plant Biology. McGraw-Hill. 2011. pp. 74–76. ISBN 978-0-07-122212-9.