The Green Revolution turned Punjab and Haryana into India’s granary. It also left patches of that same land too salty to grow anything on.
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Indian Geography · IndGeo0018
Saline vs Sodic: Two Salt Problems, Two Fixes
Saline Soil
Problem: high soluble salts near the surface.
Fix: leach with good water, given proper drainage.
Fix: leach with good water, given proper drainage.
Sodic (Alkaline) Soil
Problem: high exchangeable sodium.
Fix: gypsum first, to swap in calcium, then leach.
Fix: gypsum first, to swap in calcium, then leach.
Root cause
Green Revolution-era canal irrigation, feeding water-intensive crops, raised water tables across Punjab, Haryana, and western UP — pulling salts upward as that water evaporated.
A cost of the food-grain success story
Roughly 6-7 million hectares of India’s land are salt-affected — reh, usar, kallar — concentrated in the very Indo-Gangetic belt that anchors the country’s food-grain output.
Must Know
🏛️ Must Know
Where Saline and Alkaline Soils Form
- How They Form Saline and alkaline soils form when water evaporates and leaves concentrated salts behind, near the surface.
- Local Names In India, these soils go by several local names: reh, usar, or kallar.
- Where They Concentrate They concentrate in the Indo-Gangetic plain, especially the canal-irrigated tracts of Punjab, Haryana, and western Uttar Pradesh. They also appear in the Deccan’s black-soil belt, Gujarat’s Rann of Kutch, and coastal areas like the Sundarbans.
- Why They’re a Problem High salt or sodium content makes these soils largely unusable for most crops, without treatment.
Good to Know
📘 Good to Know
Saline vs Sodic, and Irrigation as the Root Cause
- Two Related Problems Saline soils carry high soluble salts. Sodic, or alkaline, soils carry high exchangeable sodium instead, a related but distinct problem.
- Fixing Saline Soil Saline soils are treated by leaching. Good-quality water flushes the salts out, given proper drainage.
- Fixing Sodic Soil Sodic soils need a chemical fix first. Gypsum is added to displace sodium with calcium, before leaching can even work.
- Irrigation Causes Salinization Irrigation over a period of time is the primary man-made cause of soil salinization worldwide, not just in India. Green Revolution-era canal irrigation, feeding water-intensive crops, raised water tables and pulled salts upward as that water evaporated.
Organic Matter and the Sulfur Cycle
- Organic Matter Helps, Not Hurts A high content of organic matter in soil actually increases its water-holding capacity, it does not reduce it. Organic matter improves soil structure and nutrient retention too.
- Soil and the Sulfur Cycle Soil plays a real role in the sulfur cycle. Microbes convert organic sulfur from humus and crop residue into sulfate, the form plants can actually use.
📝 Previous Year Questions
UPSC CSP 2018 — What’s True About Agricultural Soils
- UPSC 2018 Only the statement on irrigation-driven salinization is correct. Organic matter increases, not decreases, water-holding capacity, and soil does play a role in the sulfur cycle. See UPSC CSP 2018 GS Paper I, Q82. View this question.
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Great to Know
🌟 Great to Know
A Cost of the Green Revolution’s Success
- The Same Policies, Two Outcomes The very policies that boosted food-grain output, assured irrigation and high-yielding seed varieties, also created the waterlogging that spreads these soils.
- Scale Salt-affected land in India totals roughly 6 to 7 million hectares, concentrated in the very belt that anchors the country’s food-grain output.
- Not a One-Step Fix Reclaiming sodic soil isn’t a one-step fix. Gypsum treatment must be followed by leaching and proper drainage, or the sodium simply returns.
- Two Sides of Green Revolution These soils sit at the intersection of two Green Revolution outcomes: dramatic yield gains on one hand, and long-term land degradation on the other.
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