In the face of the global hidden hunger crisis, it is imperative that we address the micronutrient deficiencies that silently erode our health
In rural India, biofertilisers can be fermented locally using cheap and easily accessible materials like cow dung, milk, sugars, ashes and rock dust mixed with water. Photo: Authors provided Micronutrient deficiencies pose a critical global nutritional problem with far-reaching health implications. These subtle deficiencies, unlike typical hunger symptoms associated with malnutrition, silently undermine our health, giving rise to the term ‘hidden hunger’.
As former United Nations Children’s Fund or UNICEF deputy executive director Kul C Gautam warned, “You might not feel it in your belly, but it strikes at the core of your health and vitality.”
Read more: Hidden Hunger: Every second child globally deficient in micronutrients, finds report
Despite the increase in global crop production, their nutritional quality and density have often declined, leading to a rise in micronutrient deficiencies. To address hidden hunger, we must shift from simply meeting populations’ caloric needs to ensuring that all nutrients are adequately supplied.
The World Health Organization (WHO) calls this approach nutrient security, which should be a primary goal for food security programmes.
While hidden hunger remains a global challenge, India emerges as the frontrunner, grappling with the highest prevalence of this issue. The primary cause behind this alarming trend lies in the micronutrient-depleted soils, particularly zinc, iron, manganese, copper, boron and molybdenum.
Repeated crop cultivation over extended periods without proper replenishment has resulted in the depletion of these vital nutrients from the soil system. In other cases, crops can show nutrient deficiencies when soil fertility has been compromised, which affects microbe functioning.
As a result, the nutrients are no longer available for plant uptake and remain ‘trapped’ in the soil. Indian women are particularly sensitive to the effects of micronutrient deficiencies because their needs for iron rise during menstruation, pregnancy and lactation.
Shockingly, iron deficiency affects more than half of the female Indian population and nearly two billion people worldwide.
The quality and fertility of agricultural systems are essential for ensuring that food crops are rich in micronutrients. After all, you are what you eat, as Micheal Pollan famously stated in his book, In Defense of Food.
As such, it is crucial to adopt strategies that can improve the nutrient levels in food. One approach is seed treatment, where plant breeders focus on improving nutritional quality traits when breeding for improved varieties.
Read more: Child malnutrition in India: A systemic failure
Another method is micronutrient-enriched fertilisers, which can be applied through foliar (application to plant leaves) or soil application. Applying micronutrients to the soil or plant leaves to increase the micronutrient contents of the edible parts of food crops is called agronomic biofortification.
Finally, soil regeneration is an approach that aims to restore the natural biological activity of soils, which increases the degradation of soil parent materials and, therefore, the bioavailability of certain nutrients.
The Green Transformation Pathways project by nonprofits Professional Assistance for Development Action (PRADAN) and Foundation for Ecological Security, water resource consultancy MetaMeta and sustainability research organisation AidEnvironment is exploring approaches to improve iron content in crops in Madhya Pradesh and Jharkhand.
This project wants to develop and integrate a cost-effective iron fertiliser management approach that maximises the iron concentration in food beneficial to the health of the rural people in these areas, as in Jharkhand, 65.2 per cent and in Madhya Pradesh, 54.3 per cent of the women are suffering from iron deficiencies.
One promising method involves adding iron to liquid biofertiliser and applying it to crops through a foliar application, allowing for easy absorption by the plant. This approach is particularly useful in soils where plants may have difficulty absorbing iron due to various physical and chemical properties.
Enriching biofertilisers with iron can be done by adding iron sulphate. An experiment by the Indian Council of Agricultural Research evaluated the effectiveness of soil, foliar and seed treatments of iron in alleviating its deficiency in rice.
Results showed that the foliar application of iron sulphate — a three per cent solution, thrice 40, 60 and 75 days after sowing of rice — was most effective in increasing the iron content of milled rice.
A study conducted in the southeast of Iran showed that foliar application of iron sulphate (one per cent) increased iron concentration in grains by 21 per cent.
Read more: Acute malnutrition worsened among children: NFHS-5
If iron sulphate is unavailable, a more widely available form of iron is iron oxide , which is not water-soluble and has a low bioavailability. Since most iron in the soil is oxidised, iron must be reduced and/or chelated, meaning coated by organic acids, to pass into the root.
Gramineae plants or grasses use chelation-based strategies in nature, while non-Gramineae plants use reduction mechanisms to absorb iron.
Reduction processes for iron occur naturally in the soil, but at a slow rate. They are dependent on soil physicochemical conditions and biological activity. To speed up the reduction process, a bioreactor tank can reproduce bacteria in controlled conditions, inducing highly intense bacterial activity.
Biofertiliser production may increase iron absorption by acting through the two mentioned mechanisms. Firstly, lactic fermentation reduces iron oxides and secondly, it produces organic acids like acetic and lactic with strong chelating properties.
In the context of rural India, both forms of iron (oxide and sulphate) can be transformed in the process of making biofertilisers. This fermented product can be made locally from cheap and easily accessible materials: Cow dung, milk, sugars, ashes and rock dust mixed with water.
After a month of fermentation, the solution will contain numerous minerals and compounds that feed and protect plants from insects and pathogens. Since biofertilisers are produced at home or on the farm, they are always available when needed and can be produced with locally available materials at a minimal cost.
Not only does the foliar application of micronutrient-rich biofertiliser improve nutrient security, but it also enhances crop productivity, thus creating a win-win situation for both growers and consumers.
Read more: Over 100 school children in Bihar hospitalised after eating ‘sour’ midday meal; 3rd incident in week
In Pakistan, farmers are also exploring whether foliar application of iron and zinc could effectively address the micronutrient deficiencies in staple foods by increasing their content in commonly grown crops such as chickpeas.
A chickpea spray trial was conducted on two farms in the Union Councils of Jalal Khan and Naushara, Tehsil Bhag, Balochistan, Pakistan.
The initiative was undertaken as part of the Flood Based Livelihoods Network project in association with the civil society organisation, Strengthening Participatory Organization regional centre of Quetta.
The mixture contained 200 parts per million (ppm) iron and 100 ppm zinc. The outcome of the trial showed remarkable results, as typically the chickpea crops in the region produce yields ranging from 600 to 700 kilogrammes per acre.
After the application of the spray, the yield averagely increased by 100 to 120 extra kgs per acre. This showcases the positive effect on crop productivity. To what extent the spray also enhanced the iron and zinc content in the crops, ready for human uptake, has to be further examined.
In the face of the global hidden hunger crisis, it is imperative that we address the micronutrient deficiencies that silently erode our health.
Read more: Investing in early warning, agrifood chains needed for resilient food systems: Report
By revitalising our soils and enhancing nutrient levels in crops through foliar application, we can unlock the potential to improve crop nutrient levels and enhance nutrient security.
Ruben Borge owns Rockinsoils, a consultancy in organic farming; Femke van Woesik works as programme manager at MetaMeta Research and is based in the Netherlands; Redeat Daneil is a junior natural resource management expert working at MetaMeta Research, based in Ethiopia; Frank van Steenbergen is the founder of MetaMeta and Sachin Pathania works as a team coordinator with PRADAN and is based in Madhya Pradesh.
Views expressed are the author’s own and don’t necessarily reflect those of Down To Earth
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