Micronutrients and Nutrition Security

Food security

All people at all times have access at an affordable price to the basic food they need to meet their energy requirements.

Nutrition security

Nutrition security means that every individual has access to a balanced diet that includes all essential nutrients (e.g. proteins/amino acids, vitamins, nutritive trace elements). Nutrition security cannot be achieved without first having food security.

Micronutrient malnutrition

Diets deficient in micronutrients are characterized by high intakes of staple food crops (such as maize, wheat and rice), but low consumption of foods rich in bioavailable micronutrients such as fruits, vegetables, and animal and fish products.
Micronutrient deficiencies can impair cognitive development, lower resistance to disease in children and adults, and increases risks for both mothers and infants during childbirth. The costs of these deficiencies in terms of lives lost and reduced quality of life are staggering.

Micronutrients

18 elements have been shown to be essential for higher plants: carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), potassium (K), sulphur (S), magnesium (Mg), calcium (Ca), iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), boron (B), molybdenum (Mo), chlorine (Cl), nickel (Ni) and cobalt (Co).
These essential elements can be divided into:
• Primary macronutrients (N, P, K) • Secondary macronutrients (S, Mg, Ca) • Micronutrients
The main micronutrients are:
• Iron • Manganese • Zinc • Copper • Boron • Mobybdenum • Chlorine • Nickel • Cobalt
While macronutrients are found in plants at levels of 0.2 to 5.0 % or greater, plant concentrations of micronutrients range from 0.1 to 100 μg/kg.
Other micronutrients are also essential to animal and human health such as iodine (I) and selenium (Se).

	♦ AGRONOMIC FORTIFICATION
	Options available for the fertilizer industry for supplying micronutrients
	There are several ways to supply micronutrients to crops: soil application, fertigation, foliar spray, seed treatment, or combination with crop protection products. Each option has specific advantages and disadvantages depending on the nutrient, the crop and the soil characteristics. Similarly, the different product types (e.g. chelated/non-chelated, organic/inorganic, granular/fluid) have respective relative strengths. The various options have quite different impacts on the solubility and availability of the micronutrients, on the uniformity of application, as well as on health, safety and the environment. The most commonly-used methods are the following: • Dry mixing is a simple method that works well with non-granular materials. However, there are often caking problems. The most commonly-used methods are the following: • Dry mixing is a simple method that works well with non-granular materials. However, there are often caking problems. • Bulk blending is a form of dry mixing, but with granular material. The main problem is segregation of the different components, unless all the materials have similar particle sizes. Segregation generally leads to uneven application. • Complex fertilizers: This option might lead to reactions that will affect the solubility of the nutrients.Moreover, unless a micronutrient deficiency is widespread, it is often uneconomical to produce small lots of special grades. • Coated fertilizers: Micronutrients may be added as coating to straight or complex fertilizers or to bulk blends. This is a quite simple and inexpensive solution. However, it lowers the macronutrient grade. This is an obstacle in countries where only prescribed,registered grades can be marketed. • Fluid fertilizers: Micronutrients are generally applied in combination with crop protection sprays or with foliar application of macronutrients. They are generally available as prepared mixtures to prevent reactions that create water-insoluble compounds. Their use is limited in developing countries.

Agronomic biofortification

Increasing the density and balance of essential nutrient in harvested crop products, mainly by means of appropriate management of plant nutrition and crop cultural practices.

Genetic biofortification

Increasing the essential nutrient content of crops mainly by breeding plant varieties with greater efficiency of nutrient uptake from soils, enhanced nutrient translocation to edible parts or greater nutrient bioavailability. It is important to note that naturally high-efficiency varieties will remove more nutrients from soils which must therefore be replaced by judicious fertilizer use to avoid nutrient mining and depletion. As a consequence, agronomic and genetic biofortification strategies are inextricably linked in meeting future ‘nutrition security’ goals.

Farming for Health

'Farming for Health' describes the utilization of agricultural farms, farm animals, plants and landscapes as a base for promoting human mental and physical health and social well-being.The concept has been developed to meet nutrition security goals.It originates from Wageningen University in the Netherlands and is now represented by an international community of practice of researchers.

Billions of people, mostly in developing countries, suffer from micronutrient malnutrition, sometimes referred to as “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 also widespread. Micro-enriched fertilization is considered one of the most promising ways to fight malnutrition in soils, livestock and people.

Zinc deficiencies and zinc fertilization Zinc is an essential micronutrient needed by crops and people. Almost half of the world’s cereal crops are deficient in zinc, leading to poor crop yields. Research has shown that areas with zinc-deficient soils are often regions with widespread zinc deficiency in humans. In fact, one-third of the world population is at risk of zinc deficiency, ranging from 4 to 73% depending on the country. Zinc deficiency is the fifth leading risk factor for disease in the developing world. Providing micronutrients, including zinc, to humans is one of the four quick-win solutions to major global problems identified in the Copenhagen Consensus from an international panel of distinguished economists.   Zinc is essential for human health Zinc is a key micronutrient needed for a wide range of biochemical, immunological and clinical functions in humans. Zinc deficiency affects: physical growth, the functioning of the immune system, reproductive health and neurobehavioral development, among others.  Preventive zinc supplements are important in reducing infant morbidity from diarrhea and pneumonia. To combat zinc deficiency, five intervention strategies can be used: Supplementation using medicines; Food fortification through the incorporation of zinc additives in food; Dietary modification/diversification; Genetic biofortification through plant breeding and Agronomic biofortification through zinc fertilization. These five intervention strategies may be used individually or in combination, depending on the setting, target group and degree of zinc deficiency. The amount of zinc absorbed by the human body is a function of dietary intake of both zinc and phytate (a phosphate storage compound), because the ratio between these two substances affects the bioavailability of zinc. Meeting the needs for absorbed zinc requires an increase in the zinc content and/or a decrease in the phytate content. Zinc deficiencies in soils Many agricultural countries around the world are affected by zinc deficiencies. In China, zinc deficiency occurs on around half of the agricultural soils, affecting mainly rice and maize. In India, zinc-deficient soils occupy almost 50% of the agricultural area and are a critical constraint on yield, but crops are highly responsive to zinc fertilization. In Turkey, major yield and quality benefits in wheat have been obtained with the widespread use of zinc fertilizers, where half of the cereal growing land is zinc-deficient.    Addressing zinc deficiencies through zinc fertilization Experiments show that soil and foliar application of zinc fertilizer can effectively reduce the phytate:zinc ratio in grain. People who eat bread prepared from zinc enriched wheat show a significant increase in serum zinc, suggesting that the zinc fertilizer strategy is a promising approach to address zinc deficiencies in humans. Where zinc deficiency is a limiting factor, zinc fertilization can increase crop yields. Balanced crop nutrition supplying all essential nutrients, including zinc, is a cost effective management strategy. Even with zinc-efficient varieties, zinc fertilizers are needed when the available zinc in the topsoil becomes depleted. The combination of genetic and agronomic approaches offers great promises Plant breeding, including modern biotechnology, can improve: Zinc uptake capacity of plants under soil conditions with low chemical availability of zinc; Zinc translocation, thus elevating zinc content in edible crop parts rather than the rest of the plant; Zinc bioavailability. For optimal efficiency, zinc-efficient genotypes should be associated with complementary soil crop management (including fertilization) to ensure adequate zinc uptake by roots and thus enhance zinc nutrition of crops and humans Links between zinc and plant metabolism are not yet fully understood The mechanisms of zinc efficiency in plants grown under zinc-limiting conditions are still not fully understood, and more research is needed on this important aspect of zinc physiology.