Organic fertilizers are fertilizers that are naturally produced. Fertilizers are materials that can be added to soil or plants, in order to provide nutrients and sustain growth. Typical organic fertilizers include all animal waste including meat processing waste, manure, slurry, and guano; plus plant based fertilizers such as compost; and biosolids. Inorganic "organic fertilizers" include minerals and ash. The organic-mess refers to the Principles of Organic Agriculture, which determines whether a fertilizer can be used for commercial organic agriculture, not whether the fertilizer consists of organic compounds. Examples and sources The main organic fertilizers are, peat, animal wastes, plant wastes from agriculture, and treated sewage sludge. Minerals Minerals can be mined from fossil products of animal activity, such as greensand (anaerobic marine deposits), some limestones (fossil shell deposits), and some rock phosphates (fossil guano). Adding limestone or “liming” a soil is a way to raise pH. By raising the pH of a soil, microbial growth can be stimulated, which in turn increases biological processes, enabling nutrients to flow more freely through the soil. When nutrients flow freely they are more accessible to plants and therefore can increase plant health and mass. If the soil is already pH balanced, liming the soil, would be ineffective. Rock phosphate Raw Langbeinite Rockdust Unprocessed natural potassium sulfate Animal sources Animal sourced materials include both animal manures and residues from the slaughter of animals. Manures are derived from milk-producing dairy animals, egg-producing poultry, and animals raised for meat and hide production, or sport and recreation. Manure is an abundant resource with estimations for cattle manure in the US alone reaching two billion tons annually, and one hen has the potential to produce a cubic foot of manure every six months. By adding manure to crops it adds nitrogen, potassium, phosphorus, sulfur, magnesium and calcium. While also increasing soil stability by increasing organic material, increasing water infiltration, it can add bacteria diversity and over time reduce the impacts of soil erosion. However, there is organic manure and non-organic manure. In order for manure to be considered organic it must come from organic livestock or certified organic growers. If organic manure is not available, they are permitted to use non-organic manure as long as the animals have room to roam, are not kept in the dark, and growers abstain from using genetically modified feeds. Fresh manure, right from the stall, can cause issues because it can be