Mycorrhiza (VAM) for crops: protecting the spore on its way to the root
Mycorrhiza helps roots reach phosphorus and water, but a spore can only help if it survives the journey from the pack to a living root. Here is how Dr. Mathur's hydrogel-bead concept aims to protect it, and how to get the best from VAM today.
Key points
- Mycorrhiza (VAM) is a beneficial soil fungus that partners with the roots of most crops. Its fine threads reach beyond the roots and help the plant take up phosphorus, some micronutrients and water.
- The weak link is delivery: spores can be damaged by heat, drying and rough handling before they ever reach a root, so many products give uneven results.
- Dr. Mathur's concept encloses spores in a biodegradable hydrogel bead that protects them in the pack and opens up as it soaks up soil moisture near the roots.
- It is a technology in development. Claims about shelf life or yield will be made only after stability and field tests.
- Using VAM today: registered product, fresh stock, cool storage, apply close to roots, no fungicide mixing, and skip crops that don't form mycorrhiza.
What is mycorrhiza (VAM)?
Vesicular arbuscular mycorrhiza (VAM), also called arbuscular mycorrhizal fungi (AMF), is a group of beneficial soil fungi that live in partnership with the roots of most crops. The plant feeds the fungus with sugars. In return, the fungus sends fine threads called hyphae far out into the soil, much further than the roots can reach.
These threads act like an extension of the root system. They are especially good at reaching phosphorus, which moves very little in soil, and they also help with some micronutrients such as zinc and with water uptake. As the network grows, it helps bind soil particles into crumbs, which researchers link to better soil structure.
A few crops do not form this partnership: the mustard and cabbage family (mustard, cabbage, cauliflower, radish) and the spinach and beet family. VAM will not help them.
Why many VAM products give uneven results
VAM is alive, and it cannot be grown on its own: it needs living roots to multiply. So products have traditionally carried spores mixed with root pieces, soil or a powder carrier. These can work in the field, but they bring practical problems:
- Uneven dosing, because spores are not spread evenly through bulky material.
- Damage on the way: heat, drying out and rough handling during storage, transport and application.
- Contamination and dust in soil- and powder-based products.
- Hard to use with seed treatment or machines, and hard to mix with other inputs.
While working in the field, Dr. Mathur saw farmers struggle with exactly these viability problems across many mycorrhiza products. A spore can benefit a crop only if it survives the journey from the pack to a living root, and close enough to that root to form a partnership.
The idea: a protective hydrogel bead
A hydrogel is a network of polymer chains that can soak up and hold a lot of water. Dr. Mathur's concept uses a biodegradable polymer–hydrogel to build a small protective bead around the spore, with three layers of protection:
The bead is designed to change with the soil around it:
- In the pack: dry and compact, with the spore sealed away from heat, air and handling.
- In the soil: moisture starts to enter the bead.
- The bead swells and becomes more open.
- The spore wakes up: it can now germinate and send out threads.
- The threads reach the root and the partnership begins.
The bead is also meant to break down gradually, and it can hold water and release it as the soil around it dries, helping the young fungal network through short dry spells. As Dr. Mathur sums it up: "Protect the spore. Stabilize the formulation. Control the release. Enhance root colonization."
| Feature | Conventional carrier-based VAM | Hydrogel-bead concept |
|---|---|---|
| Handling | Often bulky and dusty | Potentially easier, less dust |
| Dosing | Variable | More uniform beads |
| Protection | Limited | Built into the bead |
| Moisture | Depends on the carrier | Held by the hydrogel |
| Release | Fast and uncontrolled | Gradual, as the bead swells |
| Seed treatment and machines | Difficult | Potentially adaptable |
These are design goals from the concept note. Each still has to be shown in tests.
What is not proven yet
Dr. Mathur's own note is careful about this, and so are we:
- This is a concept in development. No test results have been published yet.
- Shelf life: claims such as "two-year stability" can be made only after real-time and accelerated storage tests.
- Survival is not enough: the spores must still germinate and colonise roots after storage. That is the real test of the product.
- Seed treatment needs its own testing; a bead that works in soil may not suit seed coating.
- Field results, consistency across locations and benefits for yield still need to be measured, and the product will need regulatory approval.
How to get the best from VAM today
- Buy a registered product. VAM bio-fertilizers are covered by India's Fertiliser Control Order. Check the manufacturing and expiry dates and buy fresh stock.
- Store it cool and dry, out of the sun, and use it soon after opening.
- Apply it close to the roots: seed treatment, nursery beds, root dipping of seedlings or placement near the root zone, as the label advises. VAM scattered on the surface is wasted.
- Keep it away from chemical fungicides unless the label says they can be mixed. Fungicides can kill the fungus.
- Don't overdo phosphate. Very high phosphate doses reduce how well mycorrhiza colonises roots. Base fertilizer on a soil test.
- Choose the right crops. Skip the mustard and cabbage family and the spinach and beet family.
What comes next
Dr. Mathur's team is developing and testing the hydrogel-bead concept. We will report results here when storage and field data are available.
NanoKheti does not sell a mycorrhiza product today.
