Role Of Fertilizers In Improving Nutrition Value Of Crops Produce And Its Impact On Human Health

Role of fertilizers in improving nutrition value of  crops produce and its impact on human health

There are plenty convincing global human health and nutritional reasons to encourage Researchers to track in improving micronutrient density of staple food crops like Wheat & Rice, It improve crop productivity when micronutrient coated fertilizers applied micronutrient-poor soils, thus guaranteeing farmer adoption of the micronutrient enriched fertilizers once they are developed.

Humans require at least 49 nutrients to meet their metabolic needs especially Zn & Fe under global COVID-19 pandemic. The criteria include: (1) crop productivity (i.e. yield) maintained or increased to guarantee widespread farmer acceptance; (2) micronutrient enrichment levels achieved must have significant impact on human health; (3) micronutrient enrichment traits must be stable across all climatic zones; (4)Bioavailability of micronutrients in enriched seeds and fertilizers must be tested in humans to ensure that they improve the micronutrient status of people preparing and eating them in traditional ways within normal household environments;(5) consumer acceptance must be tested (taste and cooking quality must be acceptable to household members) to ensure maximum impact on nutritional health.

In Wheat, germplasm is being studied at CIMMYT with respect to the concentration of Fe and Zn in the whole grain and environmental interactions on their concentrations. In one study, the ranges in Fe and Zn concentrations (dry weight basis) in wheat grain from plants grown were 28.8±56.5 mg g±1 (mean=37.2 mg g±1; SD=4.10 mg g±1; n=132) for Fe and 25.2±53.3 mg g±1 for Zn (mean=35.0 mg g±1; SD=4.99 mg g±1; n=132). Enough genetic variation exists within the wheat germplasm to increase Fe & Zn concentrations substantially in wheat grain. There was significant genotype environmental interactions obtained for Fe & Zn grain concentrations, there was still a strong genetic component to Fe & Zn accumulation in the grain. This finding indicates that it should be possible to improve Fe & Zn levels in wheat grain simultaneously through fertilizer enrichment with Zn & Fe & no negative linkage between grain yield and Fe & Zn density in the grain.

In Rice, Researchers at IRRI have been evaluating the genetic variability of Fe concentration in rice grain. All Rice genotypes were tested in the field at the same location during the same year. There was about a 4-fold difference in Fe and Zn concentrations suggesting some genetic potential to increase the concentrations of these micronutrients in rice grain. Among the varieties with the highest grain-Fe concentrations (i.e. ranging from about 18 mg g±1 to 22 mg g±1) found were in a number of aromatic rice varieties.

Zn deficiency is the most common micro- nutrient deficiency problem in soils, particularly in rice- wheat cropping systems. The Zn deficiency problem is related to low levels of plant-available Zn concentrations caused generally by high soil pH, high CaCO3, low organic matter and low soil moisture. Deficiencies of other micronutrients have been also reported, but their prevalence is much lower than the Zn deficiency problem.

Importance of Zn deficiency for human health:

Under the COVID-19 pandemic, Zn deficiency in humans has an increasing attention, not only by nutritional and medical scientists, but also by economists. Zinc deficiency together with vitamin A deficiency has been identified as the top priority global pandemic problem facing the world. According to a WHO Report, Zn deficiency was the fifth most important risk factor responsible for illness & death.

Zinc has a number of critical functions in biological systems, including protection of structural and functional integrity of biological membranes, detoxification of highly toxic oxygen-free radicals and maintenance of gene expression and protein synthesis. Among all cations, Zn is required by the largest number of proteins in biological systems & Zn-binding proteins makeup nearly 10% of the proteome of eukaryotic organisms as well as better protection from infectious diseases like COVID-19 pandemic.

Zn deficiency impairs immune system & increases incidence of infectious diseases like Corona, diarrhea & pneumonia. Brain function & development is affected by Zn deficiency in newborns & major reason for child death for nearly 450,000 deaths in children under 5 years of age, which is 4.4% of the worldwide deaths in children in that age group. Zinc deficiency together with vitamin A deficiency has been linked to nearly 11% of the deaths of children under 5.

Zinc deficiency is a growing public health issue in Pakistan & is associated with low dietary intake of Zn. Providing Zn-enriched staple foods is an effective intervention to alleviate Zn deficiency- related public health problems.

Bio fortification of rice and wheat grains with Zn may save 0.6 million and 1.4 million DALYs each year according to the pessimistic and optimistic scenarios, respectively in Indo Pak Region. Pregnant women are very susceptible to low dietary intake of Zn. Cereal grains are not only low in Zn concentrations but also rich in anti-nutritive compounds, like phytates, which reduce bioavailability of Zn by forming insoluble Zn–phytate complexes. Therefore, cereal grains represent a very poor Zn source in the diet. Compared to animal-based foods or pulses, cereals have very low Zn concentration in grains. Growing cereals on Zn-deficient soils will further decrease grain Zn concentration, which is the current situation. A similar situation also exists in Turkey: average grain Zn concentration of 54 wheat cultivars grown on a Zn-deficient soil in Central Anatolia was 9mg Zn kg _1 dry weight, while on the soils with normal supply of Zn, grain Zn concentration was 26 mg Zn kg _1 dry weight.

These results and observations indicate importance of keeping a sufficient amount of available Zn in soil solution by applying Zn fertilizers in order to improve grain Zn concentration.

Effect of Zn-enriched urea (ZEU) on grain yield and grain Zn concentrations of aromatic rice, and economics of using Zn- enriched urea in aromatic rice–wheat cropping system

Data show average values of 2-year field trials.

ZEU=Zinc Enriched Urea

Grain yield and grain Zn concentration of rice and wheat as influenced by Zn-enriched urea applications

Data show average values of 2-year field trials

Inadequate use of Zn fertilizers: Zn fertilizers such as ZnSO4 are not readily available or their quality becomes a concern. The cost of ZnSO4 products is very high for most small farmers. Highly hygroscopic nature of ZnSO4 restricts its application to soil incorporation. Use of Zn-augmented macronutrient fertilizers would be a good strategy for widespread application of Zn in Pakistan. The fertilizers applied by farmers regularly & mostly in the country (like urea fertilizer) could been enriched with Zn-Zabardast Urea in order to promote application of Zn in the country, particularly by resource- poor farmers. In recent years excellent research work have been done by the Engro Fertilizers demonstrating impressive effects of Zn-enriched Urea fertilizers in the form of Zabardast Urea both on grain yield and grain Zn concentration in rice and wheat. Enrichment of urea fertilizers with up to 1% Zn increased grain yield as well as grain Zn concentration of aromatic rice.

When soil applied ZnSO4 has an important residual effect on growth & yield of the next crops in cropping sequence. According to the Studies depending on the rate used, soil applied ZnSO4 can be effective in the soil up to 2–3 years in correcting Zn deficiency & improving yield. The residual effect of Zn important in the wheat–rice cropping systems.

In wheat–rice systems in Pakistan very significant residual effects of ZnSO4 applied to wheat has been reported on grain yield of rice.

Additional benefits resulting from improved Zn nutrition of food crops: Increasing Zn concentration of seeds or grains contributes to better seed viability, seedling vigor & stand establishment under marginal conditions. Field trails with wheat & maize plants emerging from seeds with low Zn concentration have poor seedling vigor & reduced yield performance.

High Zn improves tolerance of plants to various environmental stress factors during early growth stages & reduces required seeding rate. Adequate Zn nutrition is very important in reducing Cd accumulation in seeds. Zinc & Cd are chemically very similar & compete for similar binding sites and transporter proteins. Adequate Zn supply has inhibitory effects on Cd uptake by roots & Cd re-translocation from leaves in to sink organs (shoot tips, seeds)

There is an urgent need for adoption of a new fertilizer policy to encourage and promote production and application of Zn-enriched fertilizers in Pakistan to improve public health contributing to crop production. According to calculations made by Dr. Howarth Bouis, a 50% increase in food prices may result in about a 30% decline in daily Fe intake that may increase Fe deficiency prevalence rate by 25% among children and women. Obviously, daily intake of Zn will also be adversely affected by rising food prices, particularly among resource-poor families, which will further exacerbate the Zn deficiency-related problems in India.

Need of Zn Fertilizer:

Nearly all Zn fertilizer field trials conducted were focused on correction of Zn deficiency problem & increasing crop yield. Very little attention has been paid to nutritional quality and Zn concentrations in edible plant parts. Now there is need in creation of awareness of the necessity to improve grain Zn concentrations

**The soil and climatic conditions of Central Anatolia in Turkey are similar to semiarid regions in the country