Can soil bacteria lower soil salt? What a 2025 maize trial found
In a greenhouse trial with three times more salt than before, maize given salt-tolerant soil bacteria survived, and the soil's salt reading fell by about half. Here is what that does and does not mean for your field.
Key points
- In a 2025 greenhouse trial, maize in soil with 1.5% salt died without help. Given salt-tolerant soil bacteria (actinobacteria), it survived and reached about two-thirds of the height of maize in normal soil.
- After 50 days, pots with bacteria showed about half the soil salt reading of pots without them (EC 4.7 against 8.9).
- The paper does not explain where the salt went. Living plants take up some salt and watering moves it, so this is a question to test, not proof that bacteria remove salt.
- To lower salt in your field today: soil test, drainage and washing with good water, gypsum only for sodic soil, organic matter and salt-tolerant crops.
Why this question matters
Salt is one of the hardest soil problems to fix. India has about 6.74 million hectares of salt-affected land (ICAR-CSSRI), from usar land in Uttar Pradesh to kharpad fields in Maharashtra's sugarcane belt.
Today, salt is lowered mainly by washing it below the roots with good-quality water and draining it away, with gypsum for sodic soils. That takes water, drainage and money. If soil microbes could help bring salt levels down, it would matter to millions of farmers. That is the question behind this trial.
For the full background on salty soil, including how to tell saline from sodic soil, see our guide Farming in salty soil: what beneficial microbes can do.
What the researchers tested
The study was published in 2025 in a Springer conference volume, The Green Revolution: Building Sustainable Solutions. Its authors are K. Ravi Kumar, Dr. Abhishek Mathur, Garima Awasthi and Kumud Kant Awasthi, from Vivekananda Global University, Jaipur, and industry research centres in Hyderabad. Dr. Mathur, then at the R&D centre of Prathista Industries, was the second author.
It builds on the same team's 2023 trial, which used 0.5% salt with maize and sorghum. This time they made the test much harder:
- Found salt-tolerant bacteria in soil taken from around plant roots in salty fields near Machilipatnam, Andhra Pradesh, and grew actinobacteria from it.
- Made pots very salty: 10 kg of soil each, with 1.5% common salt mixed in (about 150 g per pot).
- Grew maize three ways: normal soil; salty soil with the bacteria; salty soil without them.
- Measured plant height and leaf width, and tested the soil for salt (EC), pH and nitrogen.
What they found
| Soil | Height, day 10 | Height, day 50 | Soil salt (EC) |
|---|---|---|---|
| Normal soil | 29–32 cm | 58–67 cm | 0.3 |
| Salty soil + bacteria | 18–21 cm | 40–42 cm | 4.7 |
| Salty soil only | 2 cm | died | 8.9 |
Height ranges show the two values reported for each group. EC in dS/m.
- Without bacteria, the maize died. By day 10 it was barely 2 cm tall.
- With bacteria, it survived and reached about two-thirds of the height of maize in normal soil. Its leaves were as wide as those of maize in normal soil.
- The soil salt reading was about half in pots with bacteria (4.7 against 8.9), though still far saltier than normal soil (0.3).
In simple words: even in very salty soil, the bacteria kept maize alive, and their pots ended up less salty. Whether the bacteria themselves lowered the salt is the open question.
Where did the salt go?
The paper reports the lower salt reading but does not explain it. Several things could be at work, and this trial cannot tell them apart:
- The plants took some up. Living maize draws water, and some salt with it, into its roots and leaves. In pots without bacteria the plants died, so they took up little salt.
- Water moved some. If pots were watered and drained, some salt may have washed out. The paper does not describe how the pots were watered.
- The bacteria may have changed the soil. Research elsewhere suggests some salt-tolerant bacteria make sticky substances that can hold sodium around roots. That was not tested here.
- Measurement. The paper gives one salt reading per group, with no statistics.
To answer the question properly, the salt in the plants, in the drainage water and in the soil all needs to be measured, ideally in a field trial. We have asked the authors about this and will update this page.
What this study does not tell us
- It was a greenhouse pot trial with salt added by hand at one level, not a salty field.
- It reported results for maize only, with two values per group and no statistics.
- It did not measure yield.
- It does not show where the salt went, so it is not proof that bacteria remove salt.
- It did not name the bacterial strain, and no product was made from it.
- Some numbers in the paper are reported inconsistently (the length of the trial, soil pH, a "53% reduction" figure, and soil nitrogen given per hectare per year from a pot trial), so we use only the plant heights and soil salt readings.
Even so, two trials by this team now point the same way: the right soil bacteria can keep a salt-sensitive crop alive in salt that kills it otherwise.
How to lower salt in your field today
Until bacteria are proven in fields, these are the proven steps (details in our salty-soil guide):
- Test first: pH and EC, and sodium (ESP) if the pH is above 8.5.
- Wash and drain: good-quality water, field drains, no flooding; subsurface drainage for waterlogged kharpad land.
- Gypsum only for sodic soil, as your soil report advises.
- Add organic matter: farmyard manure, compost, pressmud, green manure such as dhaincha.
- Grow salt-tolerant crops and varieties, and ask your KVK about ICAR-CSSRI's salt-tolerant bio-fertilizers (Halo-Azo, Halo-PSB).
What comes next
The authors call this early work and say more research is needed before it can help farmers in the field. The next steps are clear: name the bacterial strain, track where the salt goes, and test it in real salty fields.
NanoKheti does not sell these bacteria or any product for saline soil. This work is at the research stage.
