A variety of different sources of plant nutrients are available for use in the form of organic fertilizers (manure, alfalfa meal, blood meal, fish meal, wood ashes and waste from water or sewage treatment) 7 or synthetic fertilizers. In 2016, it was estimated that nearly half of the population was supported using synthetic fertilizers in 2015, indicating that both synthetic and non-synthetic fertilizers are necessary to adequately feed the human population of the world. For example, in 2020, 147 million tons of ammonia, 219 million tons of phosphate, and 44 million tons of potash were produced , while the demand for ammonia, phosphate, and potash in 2020 were predicted to be 119 million tons, 46 million tons, and 37 million tons, respectively.