Soil Salinity EC & What Salt Costs Your Yield
Rates rice
Enter the soil EC and choose your crop to get the relative yield, the yield loss percent, the salinity class and the crop threshold — using the Maas–Hoffman model.
Enter your reading
Many crops restricted; choose tolerant ones.
Next: if loss is high, leach salts with good-quality water, improve drainage, add gypsum for sodic soils, and pick salt-tolerant crops/varieties.
Thresholds & slopes are standard Maas–Hoffman values for soil-saturation-extract EC (ECe); irrigation-water EC relates differently.
Soil salinity — key facts
- Yield loss
- slope × (EC − threshold)
- Non-saline
- ECe < 2 dS/m
- Moderate
- ECe 4–8 dS/m
- Very strong
- ECe > 16 dS/m
- Rice / wheat
- threshold 3.0 / 6.0
- Cotton / beans
- threshold 7.7 / 1.0
- Manage by
- leaching, drainage, gypsum
- Privacy
- Runs in your browser; nothing uploaded
Salt you cannot see still steals the yield
Soluble salts raise the osmotic stress in the soil and lower the water that roots can actually draw, so a crop on salty ground works harder for less. Below a crop's threshold EC there is no penalty, but above it every extra deciSiemens per metre costs yield in a steady, predictable way. Because crops differ enormously in tolerance — beans buckle where cotton barely notices — knowing your soil EC and the right crop threshold is the difference between a full harvest and a quiet, expensive loss.
This tool gives the relative yield, the yield loss percent, the salinity class and the crop threshold from your soil EC using the Maas–Hoffman model. Use it to choose salt-tolerant crops, judge whether your land needs leaching or reclamation, and prioritise drainage or gypsum on sodic ground. Pair it with the Gypsum Requirement, CEC & Base Saturation and Lime Requirement tools to plan a full soil-health programme.
See the real cost
Yield loss percent at your soil's EC.
Match crop to soil
Pick crops whose threshold suits the salt.
Read the class
Know if soil is slight, moderate or strong.
Plan reclamation
Leaching, drainage and gypsum where needed.
Frequently Asked Questions
What is soil salinity and EC?+
Salinity is the amount of soluble salts in the soil, measured as electrical conductivity (EC) in deciSiemens per metre (dS/m). More salt conducts more current, so a higher EC means a saltier soil. Salts raise the osmotic stress on roots and lower the water actually available to the crop, which is why salinity reduces yield.
How is yield loss from salinity calculated?+
The tool uses the Maas–Hoffman model: every crop has a threshold EC below which there is no loss, and a slope giving the percent yield lost for each extra dS/m above it. Yield loss % = slope × (EC − threshold), and relative yield = 100 − loss. Below the threshold the relative yield is 100%.
What are the salinity classes?+
By saturated-paste EC (ECe) in dS/m the classes are: under 2 non-saline, 2–4 slightly saline, 4–8 moderately saline, 8–16 strongly saline, and over 16 very strongly saline. The class is a quick guide to severity, while the crop threshold tells you whether that level actually hurts the specific crop you grow.
Why do crop thresholds differ?+
Crops vary widely in salt tolerance. Sensitive crops such as beans are hit at a low threshold (about 1.0 dS/m), while tolerant crops carry on much higher — rice around 3.0, wheat about 6.0 and cotton about 7.7 dS/m. Matching crop choice to your soil's EC is one of the most effective ways to keep yielding on salty land.
What is the Maas–Hoffman model?+
It is the standard threshold-and-slope model for crop salt tolerance: yield stays full up to a crop-specific threshold EC, then declines linearly by a fixed slope for each dS/m beyond it. It gives a clear, practical estimate of the yield you can expect at a given soil salinity for each crop.
How do I lower soil salinity?+
The main tool is leaching: apply good-quality water in excess of crop use, with adequate drainage, so salts move below the root zone. Choosing salt-tolerant crops, improving drainage and avoiding saline irrigation water all help. For sodic soils, gypsum is added to displace sodium before leaching is effective.
What is the difference between saline and sodic soils?+
Saline soils have high total salts (high EC) and are managed mainly by leaching with good water and drainage. Sodic soils have a high proportion of sodium that destroys structure and seals the soil; they need gypsum to replace the sodium with calcium first, then leaching. Some soils are saline-sodic and need both.
Does irrigation water salinity matter too?+
Yes — irrigating with salty water adds salt every season, and without enough leaching it builds up in the root zone. Keep the soil EC under your crop's threshold by using the best water available, applying a leaching fraction, and watching the EC of both soil and water over time.
Can I still farm strongly saline soil?+
Often yes, by growing salt-tolerant crops and managing salts actively — leaching, drainage, raised beds, and gypsum where the soil is sodic. The yield loss figure here shows what a sensitive crop would suffer, which is exactly why crop choice and reclamation matter on strongly saline land.
Are these figures exact?+
They are solid planning figures based on published thresholds and slopes. Real yield depends on variety, climate, soil, drainage and how salinity is distributed in the root zone, so use the result to guide crop choice and management and confirm with a proper soil test of your field.