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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.
Micronutrients are sold in several forms. Sulphate salts are cheap but can be locked up in alkaline soil. Chelates and organic complexes cost more but stay available longer and are gentle in sprays. Fortified fertilizers and mixtures save an application but may not match the field. Biofertilisers and manure keep nutrients available over time. The right choice depends on the soil, the crop and the test result.
By Gafar Laiya and the Gujarat Bio Organics team. Updated November 2026.
Side by side
| 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 |
How to choose
- Start from a soil test: buy only the nutrients that are short.
- On alkaline and calcareous soils, prefer foliar sprays or chelates made for high pH over plain sulphates in the soil.
- For boron, choose a product with a clear content and follow the dose exactly.
- For several shortages at once, a mixture can help if it matches the test.
- Read the label: nutrient content, form and compatibility.
Mixing and compatibility
- Do a jar test before mixing products in one tank.
- Do not mix zinc sulphate with phosphate fertilizers.
- Some chelates and organic complexes mix better with other products; check the label.
- Spray in the cool part of the day.
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.
Read next
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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 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
- Sugarcane guide and Immunity Sugarcane Special
- Potato guide and Immunity Potato Special
- Cotton guide and Immunity Cotton 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 is a chelated micronutrient?
A micronutrient held by an organic molecule so it stays dissolved and available longer, in soil or in a spray.
Are chelates worth the extra cost?
On alkaline and calcareous soils and for sprays, often yes, because plain sulphates are locked up quickly. Match the chelate to the soil pH.
Is a micronutrient mixture better than single products?
Only if its contents match what the soil test shows is short.