Key facts and figures

• Nutrients are the substances that living organisms need to fuel growth and to ensure the functioning of their metabolisms.
• There is no substitute for each nutrient, but many of are needed in combination to ensure various biological functions.
• Organic sources of nutrients are not plentiful enough to produce enough crops for today’s growing population. Substituting farmyard manure for the current supply of mineral fertilizers would require at least a fourfold increase of livestock worldwide.
• Any organic forms of nutrients must be converted into inorganic forms before they can be used by plants.

• Both organic and inorganic forms of nitrogen can be implicated in unwanted impacts.
• Organic sources of nutrients have both advantages and disadvantages. Appropriate management is necessary to manage the associated health risks.
• As a component of DNA/RNA, amino acids and protein, nitrogen is one of the primary building blocks of life.
• Researchers estimate that about half of today’s food supply is dependent on the nitrogen originating from ammonia-based fertilizers.
• The majority of phosphate found in the human body is concentrated in the bones.
• Today, most phosphorus is derived from phosphate rock, which contains several natural impurities, including heavy metals, and may contain low levels of naturally occurring radioactivity.
• Manufactured fertilizers, animal manures, biosolids and recycled industrial wastes may all contain heavy metal impurities.
• There are several options for minimizing the accumulation of heavy metals in soils over time. The first is to limit the addition of heavy metals. Another option is to minimize the transfer of heavy metals from the soil into the food chain through appropriate agricultural management practices.
• Potassium chloride is commonly used as a substitute for table salt, and is the only fertilizer product recommended for direct human consumption.
• Potassium is not considered to have any negative impacts on our health or the environment.
• Micronutrient fertilization can enhance the presence of non-nutritive health-promoting factors like anti-oxidants in crops.
• As is the case with many industrial products, fertilizers, their raw materials and intermediates need to be handled with care.
• Particular care needs to be taken to prevent ammonium-nitrate based products from becoming adulterated (accidentally or for criminal purposes) and to ensure that anhydrous ammonia is not stolen to make methamphetamines.
• Reviews of statistically valid studies on the impacts of different sources of nutrients on the nutritional content of crops indicate little or no difference.