Composting Animal Wastes with Magnesium: A Novel Method of Stabilizing Nitrogen and Phosphorus

摘要

Animal wastes that are composted generally lose valuable fertilizer elements such as nitrate and phosphate by dissolution and volatilization. Bacterially produced insoluble compounds such as ammonium magnesium phosphate (struvite) can bind up the plant nutrients and provide a slow-release nitrate and phosphate source suitable for crop application. A wide variety of magnesium sources can be used to form struvite during waste digestion or composting. Preliminary work indicates magnesium compounds produced by low-temperature calcining of dolomite and treatment of the fired material with organic acids produces a useful waste treatment additive than can be provided in a safe, transportable form. The ability to compost and store animal wastes for extended periods of time without losing nitrogen or phosphorus makes it practical to stockpile compost and allow time for the die-off of dangerous enteric bacteria; such as E. coli. Using aged struvite compost (a synthetic guano) can make organically-grown vegetables much safer for human consumption.