Soil fertility is the ability of a soil to sustain plant growth by providing essential plant nutrients and favorable chemical, physical, and biological characteristics as a habitat for plant growth. Plant nutrients include the macronutrients nitrogen, phosphorus and potassium, sulfur, calcium and magnesium. Micronutrients are essentially boron, chlorine, copper, iron, manganese, molybdenum and zinc. Fertilizers are chemical or natural substance or material that is used to provide nutrients to plants, usually via application to the soil, but also to foliage or through water in rice systems, fertigation or hydroponics or aquaculture operations. Nutrient sources include chemical and mineral fertilizers, organic fertilizers, such as livestock manures and composts, and sources of recycled nutrients.

The impacts of soil fertility are reflected in most of the Sustainable Development Goals, as they contain economic, social and environmental aspects. The main function provided by a fertile soil is the provision of food, which is very important considering FAO’s Zero hunger objective. A fertile soil also provides essential nutrients for plant growth, to produce healthy food with all the necessary nutrients needed for human health. Moreover, fertility has an impact on activities with an economic impact and is therefore related to economic growth and the fight against poverty. Finally, good management of soil fertility can help reduce soil, water and air pollution, regulate water resources availability, support a diverse and active biotic community, increase vegetation cover and allows for carbon neutral footprint.

Soil fertility is crucial for agricultural productivity and therefore for food security. It can be maintained or increased through several management practices. Farmers can improve soil fertility and soil health by optimizing soil nutrient management in terms of maximizing net returns, minimizing the soil nutrients depletion, and minimizing nutrient losses or negative impacts on the environment. Governments should promote sustainable agricultural practices, technologies and management in order to improve soil fertility and nutrient management as a whole, such as Integrated Soil Fertility Management (ISFM) and Sustainable Soil Management (SSM). The International Code of Conduct for the Sustainable Use and Management of Fertilizers promotes practices including nutrient recycling, and agronomic and land management to improve soil health; it recommends regulation related to the sale, distribution and labelling of fertilizer products, wherever appropriate. It also promotes capacity development and education programmes for all stakeholders involved in the fertilizer value chain, and encourages developed countries to assist others in developing infrastructures and capacity to manage fertilizers throughout their life cycle.