Facts about sustainable nutrient management and the triple planetary crisis

What do we mean by nutrients and what is the problem?

• Nutrients are natural chemical substances that are essential to sustaining life - needed by plants, animals and people.
• Macronutrients are those that are needed by the plants in larger quantities and include: nitrogen, phosphorus, potassium, sulphur, magnesium, and calcium.
• Micronutrients, including minerals such as boron, chlorine, copper, iron, manganese, zinc and nickel are still vital for healthy growth but needed in smaller quantities.
• As humans we can only access these nutrients through the food we eat. To make sure that the food we eat is sufficiently nutritious, it is important to ensure crops receive the appropriate nutrients supply while they are growing.
• Discussions on nutrient management tend to focus on Nitrogen and Phosphorus - around half of the world’s food security is dependent on these two nutrients.
• A recent assessment of the earth’s planetary boundaries shows that these important nutrient cycles have been disrupted by human activities, such as the misuse of fertilizers, resulting in increased volumes of runoff and wastewater. This puts the earth’s systems at high risk of fundamental change.
• Wastewater is the major carrier of nutrients to freshwater and marine ecosystems. Nutrients are present in urban and industrial wastewater, agriculture and aquiculture effluents, run-off and urban storm water.
• An imbalance in nutrient management occurs from both a lack and an excess of these nutrients. Nutrient deficiency is called nutrient mining. It occurs where there is insufficient access to fertilizers. The plant nutrients removed by growth and harvesting are not replenished, resulting in decreased soil health, lower yields or even failed crops. This can undermine food security.
• Pollution from excess nutrients through overuse or misuse of fertilizers, as well as insufficient municipal and industrial wastewater management is a key driver of biodiversity loss, undermining ecosystem function and ecosystem services in soils, lakes, rivers, streams and coastal waters.
• Developing strategies to manage nutrients sustainably is critical to tackling each aspect of the triple planetary crisis.