Protein hydrolysates and nutrient-use efficiency
What amino acid and protein hydrolysate biostimulants are, how they are reported to help nutrient uptake and stress recovery, and how to use them.
Read the previous partSalt and drought both stop a crop from getting water, and salt also poisons it. Fixing water, drainage and salt in the soil comes first. Biostimulants can then help the plant cope, for example by supporting roots and protective compounds, but they cannot remove salt from the soil or make up for no water.
Part 6 of 6 in the Plant Science Series by Gafar Laiya: plant physiology and biostimulant science, in plain language. Published 30 October 2026.
How salt and drought hurt a crop
| Stress | What happens in the plant | What the grower sees |
|---|---|---|
| Salinity, first phase | Salt around the roots makes it hard for the plant to take up water, so growth slows quickly | Slow growth, small leaves, darker blue-green foliage |
| Salinity, second phase | Sodium and chloride build up in older leaves and become toxic | Leaf-tip and edge burn, early leaf drop |
| Drought | The plant closes its leaf pores to save water, which cuts photosynthesis; harmful molecules build up | Wilting, rolled leaves, poor fruit and grain filling |
| Both together | Salty soil makes drought worse, because roots find it harder to pull water | Patchy, stunted crop that worsens in dry spells |
Fix the cause first
| Problem | Check | Fix |
|---|---|---|
| Salty soil or water | Test soil and irrigation water for EC. A soil above 4 dS/m (saturated paste) is generally classed as saline | Leach with good-quality water where drainage allows; improve drainage; use gypsum on sodic soils where the test says so |
| Poor drainage | Look for standing water and a hard layer | Open drains, deep tillage, raised beds |
| Water running short | Check irrigation interval and root depth | Irrigate at the sensitive stages, use drip, mulch the soil to cut evaporation |
| Low organic matter | Soil test for organic carbon | Add compost or manure; see why yields fall on old land |
Biostimulants should come after these steps, not instead of them. See how to take a soil sample to start.
Where biostimulants may help
| Type | How it is reported to help | Typical use |
|---|---|---|
| Seaweed extracts | Contain betaines and other protective compounds; studies report better root growth and stress tolerance | Foliar or drip before and during stress |
| Amino acids and protein hydrolysates | Support recovery from stress and nutrient uptake | Foliar after or during stress |
| Humic and fulvic substances | Support root growth and the root zone; may help in poor soils | Soil or drip, with organic matter |
| Selected microbial products | Some support roots and nutrient access under stress | Seed, soil or root zone, as the label says |
Studies report benefits, but the results are not uniform. They depend on the product, the dose, the timing, the crop and how severe the stress is.
Timing matters
- Apply before a stress you can predict, such as a hot spell or a dry stretch, rather than after the damage.
- Spray in the cool part of the day.
- Keep irrigation steady; biostimulants do not replace water.
- Follow the label and do not exceed the dose.
A simple plan for a salty or dry field
- Test soil and water for salt, pH and nutrients.
- Fix drainage and water supply, and add organic matter.
- Choose crops and varieties suited to your salt and water level.
- Apply biostimulants at the sensitive stages as a support.
- Leave an untreated strip and compare the results.
- Keep records so you can improve next season.
What biostimulants cannot do
- They cannot remove salt from the soil.
- They cannot replace water in a drought.
- They cannot make an unsuitable crop thrive in a very salty field.
If you want help choosing a programme for your crop and conditions, send us the crop, stage and a soil or water test and we will suggest a plan.
Written by Gafar Laiya, founder of Gujarat Bio Organics, working with farmers since 2006. 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
Can biostimulants fix salty soil?
No. Salt has to be managed with water, drainage and sometimes gypsum. Biostimulants can only help the plant cope.
Which biostimulant is best for drought?
No single one. Seaweed extracts, amino acids and humic substances are commonly used to support crops under stress, but water management comes first.
When should I apply a stress biostimulant?
Before a predictable stress, or at the first signs, and at sensitive crop stages such as flowering.
How do I know if my soil is saline?
Test the soil for electrical conductivity (EC). A reading above 4 dS/m on a saturated paste is generally classed as saline. Also test your irrigation water.
Further reading
- Munns R, Tester M (2008). Mechanisms of salinity tolerance. Annual Review of Plant Biology 59:651-681.
- Farooq M, Wahid A, Kobayashi N, Fujita D, Basra SMA (2009). Plant drought stress: effects, mechanisms and management. Agronomy for Sustainable Development 29:185-212.
- Rouphael Y, Colla G (2020). Biostimulants in agriculture. Frontiers in Plant Science 11:40.
These are starting points for readers who want to look at the research. Findings differ between crops, products and conditions.
Continue the series
See all six parts of the Plant Science Series.
For business buyers and formulators
Technical notes on our business site (b2b.gujaratbio.com), for manufacturers, importers and brand owners:
Biostimulant manufacturer in India: bulk, private label and export
Send us your enquiry
Tell us your crop, the problem and your location, and send a photo if you can. Our team replies on WhatsApp or calls you with what to check, which product suits and where to buy it near you.