Billions of people, mostly in developing countries, suffer from micronutrient malnutrition, sometimes called “hidden hunger”. The nutrient deficiencies most commonly associated with human health problems on a global scale are iron, zinc and iodine, but selenium and fluorine deficiencies are widespread as well. According to a report of the World Health Organization (WHO) on the risks factors responsible for development of illnesses and diseases, Zn and Fe deficiencies rank fifth and sixth among the ten most important factors in low income countries.

IFA has recently launched an initiative aimed at assessing the linkages between fertilizer applications and human health, with the ultimate objective of developing practical fertilizer recommendations combining crop productivity, environmental protection and human health objectives. IFA also works in close partnership with the HarvestPlus Biofortification Challenge Program.

Micronutrient deficiencies in crops

Micronutrient deficiencies are widespread. 50% of world cereal soils are deficient in zinc and 30% of cultivated soils globally are deficient in iron. These are only the most severe deficiencies. Moreover, steady growth of crop yields during recent decades (in particular through the Green Revolution) actually compounded the problem by progressively depleting soil micronutrient pools. This trend will continue unless appropriate steps are taken.In many places, the supply of micronutrients to crops is low compared to their uptake. Therefore, it is imperative to look at micronutrient balances urgently.

In general, farmers only apply micronutrients when crops show deficiency symptoms, while micronutrient deficiencies decrease yields before symptoms appear. Some common farming practices (such as liming acid soils) contribute to widespread occurrence of micronutrient deficiencies in crops by decreasing the availability of the micronutrients present in the soil. Also, extensive use of glyphosate is increasingly suspected to impair micronutrient uptake by crops, especially with regard to manganese, iron and zinc.

The negative agronomic impacts of micronutrient deficiencies

Micronutrient deficiencies have the following impacts on crops:

• affect yields, either directly or indirectly;
  
• lead to less efficient use of other essential plant nutrients;
• can trigger nitrogen losses to the environment;
• result in lower water use efficiency;
• weaken crops’ capacity to withstand difficult conditions;
• contain undesirable element (like cadmium) with higher risks of having non-nutritive trace elements present in edible parts;
• crop quality.

The promise of micro-enriched fertilization

The returns by applying micronutrient-enriched fertilizers could be huge. Economists estimate very high returns in terms of health, social and economic development when micronutrient deficiencies are eliminated. A report by the World Bank and the Asian Development Bank stated that eliminating micronutrient deficiencies could:

• improve GDP by more than 5%;
• enhance the intellectual capacity of populations by more than 10%;
• enhance worker productivity by 30 to 70%;
• reduce maternal deaths by up to 50%.

Food biofortification using plant breeding (genetic biofortification) and/or micronutrient fertilizers (agronomic biofortification) can contribute to this goal.

The contribution of the fertilizer industry

In contrast to food security, nutrition security has traditionally been viewed as the realm of the health professionals. Yet, the nutrition challenge cannot be solved solely by the health sector: the entire agri-food chain has a vital role to play. Producing more nutritious food and feed, or “farming for health”, should be a central objective, and this means increasing micronutrient content.

The compelling market development opportunities offer a strong business case for the fertilizer industry to make an important contribution to human well-being by offering micronutrient products.

Priority should be given to zinc, selenium and boron

Scientific experiments show that zinc and selenium are the nutrients that can be most effectively provided to humans via micronutrient fertilization. Fertilizers also seem to be an effective way to supplement human diets with boron and, possibly iodine. Alternative channels appear to be more appropriate for increasing human consumption of the other essential micronutrients

Economic and health incentives differ between two groups of nutrients

The fertilizer industry can play a significant and strategic role in those areas where populations suffer from deficiencies of zinc, selenium and boron. However, from a market development perspective, it is necessary to distinguish between those nutrients that have a benefit for crop production (zinc and boron) and those that are not known to be beneficial to plants (selenium).

Increasing the supply of zinc and boron fertilizers should suffice to promote their use. Their return on a farmer's investment may be more than tenfold. But, inadequate quantities of essential crop nutrients may lead to significant income losses for farmers. This provides a strong incentive for the use of the nutrients that have a direct benefit for both crop and human well-being.

Regarding micronutrients with human health benefits but no confirmed advantage for crop yields or quality, policymakers must provide the incentive for the farmers to apply the appropriate fertilizer. Selenium is a case in point. Where selenium deficiencies constitute a major threat to human well-being, public health policies could reward farmers for corrective fertilization. This could be done through subsidies for the use of fertilizers supplemented with selenium or through a premium on crops with a higher content of the targeted micronutrient. Another option is to require the addition of the needed micronutrient(s) to fertilizers through regulation, as is the case for selenium in Finland.

In parts of the world where farmers have difficulty affording fertilizers, economic incentives for the use of fertilizers to address micronutrient deficiencies for public health reasons may have the beneficial side-effect of facilitating access to the main crop nutrients in combined products.

If the appropriate enabling environment is in place, the fertilizer industry can provide the required nutrients to the farmers. Necessary preconditions include market infrastructures, access to credit for both farmers and input retailers, incentives for the use of the targeted micronutrients when there is no yield advantage, legal recognition of micronutrients in fertilizer regulations, access to information on areas affected by deficiencies. and monitoring of the toxicity risk, among others.

Once this framework is in place, the industry can develop solutions that take into account the technical and economic
constraints specific to each farming system. This might involve the different components of the fertilizer industry, from large-scale producers to small entrepreneurs operating bulk blending or coating units.