Zinc (Zn)
Growth hormones, enzymes and new leaf growth.
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Micronutrients in agriculture: what they are, how they work and why they matter
Micronutrients and trace elements for farmers: the full list, what each does, deficiency signs, fertilizer types, and how to diagnose and correct problems.
Micronutrients are the nutrients a crop needs in very small amounts: zinc, iron, manganese, copper, boron, molybdenum, chlorine and nickel. They switch on the enzymes, hormones and processes that let the crop use nitrogen, phosphorus and potassium, form chlorophyll, flower, set fruit and resist stress. A shortage of any one limits the whole crop, however much NPK is applied, and Indian soil tests show such shortages are widespread.
By Gafar Laiya and the Gujarat Bio Organics team. Updated November 2026.
On this page
What are micronutrients?
Plants need 17 essential nutrients. Carbon, hydrogen and oxygen come from air and water. The rest come from the soil and fall into groups by how much the crop needs. Micronutrients, also called trace elements, are needed in grams per acre rather than kilograms, but a crop cannot complete its life without them.
| Group | Nutrients | Needed in |
|---|---|---|
| Major nutrients | Nitrogen (N), phosphorus (P), potassium (K) | Large amounts |
| Secondary nutrients | Calcium (Ca), magnesium (Mg), sulphur (S) | Moderate amounts |
| Micronutrients (trace elements) | zinc (Zn), iron (Fe), manganese (Mn), copper (Cu), boron (B), molybdenum (Mo), chlorine (Cl), nickel (Ni) | Very small amounts |
| Beneficial elements | Silicon (Si), cobalt (Co), sodium (Na), selenium (Se) | Useful for some crops or for the microbes and animals that depend on them |
How micronutrients work
- They switch on enzymes: zinc, manganese, copper, iron, molybdenum and nickel are parts of, or activators for, enzymes that drive growth and energy.
- They make chlorophyll possible: iron and manganese are needed to form it and run photosynthesis; magnesium sits at its centre.
- They make hormones: zinc is needed for auxin, the growth hormone.
- They build cell walls: boron and calcium hold walls together, and silicon strengthens them.
- They make flowers fertile: boron, zinc and copper are needed for pollen and seed set.
- They help use nitrogen: molybdenum, nickel and sulphur turn nitrogen into protein; molybdenum and cobalt help legumes fix it.
- They defend the crop: copper, manganese, boron and silicon strengthen tissue against pests and disease.
The nutrients and trace elements, one by one
| Nutrient | Group | Main job in the plant | Shows first on | Indian soils short* |
|---|---|---|---|---|
| Zinc (Zn) | Micronutrient | Growth hormones, enzymes and new leaf growth | Young leaves | 51.2% |
| Iron (Fe) | Micronutrient | Chlorophyll formation, photosynthesis and energy | Youngest leaves | 19.2% |
| Manganese (Mn) | Micronutrient | Photosynthesis, enzymes and disease resistance | Young and middle leaves | 17.4% |
| Copper (Cu) | Micronutrient | Enzymes, lignin, pollen and seed set | Shoot tips | 11.4% |
| Boron (B) | Micronutrient | Cell walls, flowering, pollen and fruit set | Tips, flowers, fruit | 44.7% |
| Molybdenum (Mo) | Micronutrient | Using nitrate and fixing nitrogen in legumes | Old leaves | Not surveyed |
| Chlorine (chloride) (Cl) | Micronutrient | Water balance, stomata and photosynthesis | Old leaf tips (excess) | Not surveyed |
| Nickel (Ni) | Micronutrient | Using urea nitrogen and seed viability | Leaf tips | Not surveyed |
| Calcium (Ca) | Secondary nutrient | Cell walls, fruit quality and root tips | Fruit, tips, roots | Not surveyed |
| Magnesium (Mg) | Secondary nutrient | Chlorophyll, energy and moving sugars | Old leaves | Not surveyed |
| Sulphur (S) | Secondary nutrient | Protein, oil content and nitrogen use | Young leaves | 58.6% |
| Silicon (Si) | Beneficial element | Strong stems, pest and disease resistance and stress tolerance | Whole plant (weak stems) | Not surveyed |
| Cobalt (Co) | Beneficial element | Nitrogen fixation by nodule bacteria in legumes | Legume nodules | Not surveyed |
*Share of soil samples deficient, including hidden shortage, in the ICAR survey. Molybdenum, chlorine, nickel, calcium, magnesium, silicon and cobalt were not part of that survey.
India's soils: shortages are widespread
An ICAR survey of 2,42,827 soil samples from 615 districts found 58.6% of soils short of sulphur, 51.2% of zinc, 44.7% of boron, 19.2% of iron, 17.4% of manganese and 11.4% of copper, counting hidden shortages. Many fields were short of two or three nutrients together, most often sulphur with zinc, zinc with boron and sulphur with boron. Alkaline and calcareous soils, low organic matter and years of urea, DAP and MOP without sulphur or micronutrients are the main reasons.
Indian soil figures: Shukla AK, Behera SK and others (2021). Deficiency of phyto-available sulphur, zinc, boron, iron, copper and manganese in soils of India. Scientific Reports 11, 19760. Based on 2,42,827 soil samples from 615 districts in 28 states. Read the study. The figures include soils with a hidden (latent) shortage.
Common practices that miss the cause
- Applying more urea when leaves turn yellow, though yellowing from sulphur, iron, zinc or magnesium does not respond to nitrogen.
- Using NPK water-soluble fertilizer as a cure-all, though most grades carry little or no micronutrient.
- Spraying a pesticide when the crop looks weak, even when no pest is present.
- Treating the nutrient that shows the symptom, when the real limit is another nutrient, the soil pH or the water supply.
- Read why more urea does not fix yellow leaves and why a pesticide spray will not fix a nutrient problem.
Types of micronutrient fertilizers
| Type | Examples | Good points | Limits |
|---|---|---|---|
| Sulphate salts | Zinc sulphate, ferrous sulphate, manganese sulphate, copper sulphate, magnesium sulphate | Low cost, widely sold, dissolve in water | Can be locked up quickly in alkaline and calcareous soils; some react with phosphate |
| Borates and boric acid | Borax, boric acid, soluble boron products | Low cost, small amounts needed | Narrow safe range: easy to overdo |
| Molybdates | Ammonium or sodium molybdate | Tiny amounts work; easy seed treatment | Excess harms livestock fodder quality |
| Chelates | EDTA, DTPA, EDDHA forms of zinc, iron, manganese, copper | Stay available longer in the soil and mix well in sprays; some made for high pH soils | Cost more; each chelate suits a certain pH range |
| Organic complexes | Amino acid, humate, fulvate or lignosulphonate complexes | Gentle on leaves; humic and fulvic carriers also support roots | Content varies by product; check the label |
| Fortified fertilizers | Zinc-coated urea, zincated or boronated fertilizers | No extra application step | Fixed ratio may not match the field's need |
| Micronutrient mixtures | Grade mixtures of several micronutrients for soil or foliar use | One product for several shortages | May supply what is not short and miss what is; match to a soil test |
| Biofertilisers | Zinc solubilising bacteria, mycorrhiza | Free nutrients already in the soil and build soil life | Work over time; need living soil and correct handling |
| Organic manure and compost | Farmyard manure, compost, vermicompost, green manure | Supply many nutrients slowly and keep them available | Low content; need large amounts and time |
More detail: types of micronutrient fertilizers compared.
How to identify and solve micronutrient problems
- Read the leaves: old or young, pattern and colour.
- Rule out pests, disease, water and weather.
- Test the soil before the season and the leaves in orchards.
- Fix the cause first: pH, drainage, water supply and fertilizer balance.
- Correct the short nutrient by soil, foliar or seed treatment, at the right stage and the right dose.
- Build soil organic matter so the shortage does not return.
- Follow the step-by-step guide.
Our role
Gujarat Bio Organics began in 2006 with farmers on tired soil that no longer paid back the fertilizer put into it. Today lakhs of farmers from Kashmir to Kanyakumari have used Immunity products on almost every crop: from the mango farms around Somnath to the apple orchards of Himachal Pradesh and Kashmir, the tea estates of Assam and Darjeeling, and the banana, coconut and cardamom farms of Tamil Nadu, Karnataka and Kerala. See the crops and regions we serve. Our team visits fields, reads crops and soil reports with growers and builds crop programmes around what the soil can supply. This section is part of that work: plain, practical knowledge so every grower can find the real cause of a weak crop, spend less on the wrong inputs and leave healthier soil for the next generation.
Doses depend on the crop, soil and product, so this page gives methods, not amounts. Take the dose from your soil test report, the product label or your local agriculture officer or KVK. Results differ from farm to farm with soil, weather, crop and management. Farmer experiences on this site are their own reports, not a promise of results.
Nutrient guides
Iron (Fe)
Chlorophyll formation, photosynthesis and energy.
Read the guideManganese (Mn)
Photosynthesis, enzymes and disease resistance.
Read the guideCopper (Cu)
Enzymes, lignin, pollen and seed set.
Read the guideBoron (B)
Cell walls, flowering, pollen and fruit set.
Read the guideMolybdenum (Mo)
Using nitrate and fixing nitrogen in legumes.
Read the guideChlorine (chloride) (Cl)
Water balance, stomata and photosynthesis.
Read the guideNickel (Ni)
Using urea nitrogen and seed viability.
Read the guideCalcium (Ca)
Cell walls, fruit quality and root tips.
Read the guideMagnesium (Mg)
Chlorophyll, energy and moving sugars.
Read the guideSulphur (S)
Protein, oil content and nitrogen use.
Read the guideSilicon (Si)
Strong stems, pest and disease resistance and stress tolerance.
Read the guideCobalt (Co)
Nitrogen fixation by nodule bacteria in legumes.
Read the guideUnderstand and solve
Micronutrient deficiency symptoms: how to read the leaves
A field guide to reading nutrient deficiency symptoms: old leaves or new, pattern and colour, which nutrient each points to, and the look-alikes to rule out.
Read the full guideWhat happens when micronutrients are not managed
How unmanaged micronutrient shortage cuts germination, flowering, fruit set, size, brix and price, and raises fertilizer and spray costs.
Read the full guideWhen several nutrients are short: interactions and why one fix fails
How nutrients block or help each other, why a field can show one deficiency when the real limit is another, and why treating the visible symptom often fails.
Read the full guideHow to diagnose and correct micronutrient deficiency
Step by step: observe, rule out other causes, test, fix the cause, choose the method, time it right, and build soil so the shortage does not return.
Read the full guideBlogs
Why a pesticide spray will not fix a nutrient problem
Many farmers spray pesticide when a crop looks weak, even with no pest. Why that rarely helps a nutrient problem, what it costs and what to check.
Read the full guideWhy more urea or water-soluble fertilizer does not fix yellow leaves
Yellow leaves are often treated with more urea or NPK. Why that fails when sulphur, magnesium, iron or zinc is the real cause, and what to do instead.
Read the full guideMicronutrients for fruit size, quality, brix and market price
How boron, calcium, magnesium, zinc and potassium decide fruit set, size, sweetness, firmness and shelf life, and so the price a grower gets.
Read the full guideMicronutrients, soil health and sustainable farming
Why micronutrient shortage is a soil health problem, and how organic matter, residues, rotation and balanced feeding protect soil for the next generation.
Read the full guideTypes of micronutrient fertilizers: sulphates, chelates, organic and more
Sulphates, borates, chelates, organic complexes, fortified fertilizers, mixtures, biofertilisers and manure compared: strengths and limits of each.
Read the full guideHow Gujarat Bio Organics can help
Since 2006, lakhs of farmers from Kashmir to Kanyakumari have used Immunity products on almost every crop: from the mango farms around Somnath to the apple orchards of Himachal Pradesh and Kashmir, the tea estates of Assam and Darjeeling, and the banana, coconut and cardamom farms of Tamil Nadu, Karnataka and Kerala. Each Special is one formula made for one crop and its common problems. Tell us your crop, soil test and what you see, and our team will tell you what to check, whether a micronutrient correction is needed, and which Special fits your programme.
- Mango guide and Immunity Mango Special
- Apple guide and Immunity Apple Special
- Sugarcane guide and Immunity Sugarcane Special
- Potato guide and Immunity Potato Special
- Cotton guide and Immunity Cotton Special
- Citrus guide and Immunity Citrus Special
Results differ from farm to farm with soil, weather, crop and management. Farmer experiences on this site are their own reports, not a promise of results.
Questions
What are micronutrients in agriculture?
Nutrients a crop needs in very small amounts: zinc, iron, manganese, copper, boron, molybdenum, chlorine and nickel. Calcium, magnesium and sulphur are secondary nutrients, and silicon and cobalt are beneficial elements.
What is the difference between micronutrients and trace elements?
In farming the two terms are used for the same group: nutrients needed only in trace amounts. Trace elements is sometimes also used for beneficial elements such as cobalt and selenium.
Which micronutrient is most deficient in Indian soils?
Among micronutrients, zinc, followed by boron. Sulphur, a secondary nutrient, is even more widely short.
Can NPK alone give a good crop?
Only if the soil supplies enough of every other nutrient. Where a micronutrient is short, more NPK does not lift the yield.
How do I know which micronutrient my crop needs?
Read the leaf symptoms, rule out pests and disease, and confirm with a soil and leaf test.