Soil Science and Land Management — Quick Reference
India's major soil types
|---|---|---|
| Alluvial | Indo-Gangetic plains | Most fertile, river-renewed |
|---|
| Black (Regur / Vertisol) | Deccan plateau | High clay, moisture-retentive, cracks when dry — cotton |
| Red | TN, Karnataka, Odisha, Chhattisgarh | Iron-rich, low N & P |
| Laterite | High-rainfall plateau | Heavily leached, low fertility |
| Arid/Desert | Rajasthan, Gujarat, Haryana | Sandy, low water retention |
| Saline/Alkaline | Coastal, poorly drained irrigated tracts | High salt/sodium, needs reclamation |
| Forest/Mountain | Himalayan/hill regions | Acidic, high organic matter (upper layers) |
pH and nutrient availability
|---|---|---|
| < 5.5 | Strongly acidic | Al/Mn toxicity risk; P, Ca, Mg less available |
|---|
| 5.5–6.5 | Slightly acidic | Good general availability |
| 6.5–7.5 | Near neutral | Optimal for most crops |
| 7.5–8.5 | Alkaline | Fe, Zn, Mn, P less available |
| > 8.5 | Strongly alkaline/sodic | Severe lockout — reclamation often needed |
Nutrient categories
|---|---|
| Primary macro | N (growth), P (roots/flowering), K (vigour, disease resistance) |
|---|
| Secondary macro | Ca (cell walls), Mg (chlorophyll), S (protein, oil content) |
| Micro | Zn, B, Fe, Mn, Cu, Mo, Cl |
Common deficiency symptoms (quick ID)
| Nutrient | Crop example | Symptom |
|---|
|---|---|---|
| Zinc | Rice | Interveinal chlorosis, stunted growth |
|---|
| Boron | Cauliflower | Hollow stem, curd browning |
| Nitrogen | General | Uniform yellowing, older leaves first |
| Iron | General (esp. alkaline soil) | Interveinal chlorosis on new leaves |
Saline vs. sodic — the fix
|---|---|---|
| Problem | Excess soluble salts | Excess exchangeable sodium |
|---|
| Structure | Intact | Degraded |
| Fix | Leaching (+ drainage) | Gypsum first, then leach |
Soil conservation — match technique to problem
|---|---|
| Sloped-land water erosion | Contour bunding |
|---|
| Severe slope erosion | Terracing |
| Wind erosion (arid areas) | Shelterbelts/windbreaks |
| Structure decline | Cover cropping |
| Gully formation | Check dams |
Soil testing quick facts
•Sample: 8–10 sub-samples, zig-zag pattern, 0–15cm depth, composited
•Standard report: pH, EC (salinity), organic carbon, available N/P/K (± micronutrients)
•Recommendation principle: apply only what's deficient relative to crop need — not a flat universal dose
Classification quick note
Descriptive names (black soil, red soil) ≠ formal taxonomic order. Regur/black soil = Vertisol under USDA Soil Taxonomy — know both names for exams.
(needs verification — recheck against current source: Soil Health Card scheme parameters and testing cycle are subject to policy updates.)
