🌿 Essential Plant Nutrients
Fertility vs productivity, essential nutrients, macro/micro nutrients, deficiency symptoms, nutrient roles, nitrogen cycle, phosphorus and potassium in soil for CUET Agriculture
Plants require a specific set of chemical elements to grow, reproduce, and complete their life cycle. Understanding which nutrients plants need, how they absorb them, and what happens when nutrients are deficient is central to agriculture and fertilizer management.
Soil Fertility vs Soil Productivity
These two terms are often confused but have an important distinction:
| Aspect | Soil Fertility | Soil Productivity |
|---|---|---|
| Definition | Inherent capacity to supply essential nutrients in adequate amounts | Capacity to produce a specific crop under defined management |
| Scope | Nutrient supply only | Includes fertility + physical + biological + management factors |
| Relationship | Fertile soil may not be productive (e.g., waterlogged fertile soil cannot grow wheat) | Productive soil is always fertile |
IMPORTANT
All productive soils are fertile, but not all fertile soils are productive. A soil may have abundant nutrients (fertile) but be waterlogged, saline, or poorly structured, making it unproductive. Productivity = Fertility + Water + Climate + Management + Variety.
Pro Content Locked
Upgrade to Pro to access this lesson and all other premium content.
₹99 charged monthly · Cancel anytime
- All Agriculture & Banking Courses
- AI Lesson Questions (100/day)
- AI Doubt Solver (50/day)
- Glows & Grows Feedback (30/day)
- AI Section Quiz (20/day)
- 22-Language Translation (100/day)
- Recall Questions (20/day)
- AI Quiz (15/day)
- AI Quiz Paper Analysis (100/day)
- AI Step-by-Step Explanations (100/day)
- Spaced Repetition Recall (FSRS)
- AI Tutor
- Immersive Text Questions
- Audio Lessons — Hindi & English
- Mock Tests & Previous Year Papers
- Summary & Mind Maps
- XP, Levels, Leaderboard & Badges
- Generate New Classrooms
- Voice AI Teacher (AgriDots Live)
- AI Revision Assistant
- Knowledge Gap Analysis
- Interactive Revision (LangGraph)
🔒 Secure via Razorpay · Cancel anytime · No hidden fees
Plants require a specific set of chemical elements to grow, reproduce, and complete their life cycle. Understanding which nutrients plants need, how they absorb them, and what happens when nutrients are deficient is central to agriculture and fertilizer management.
Soil Fertility vs Soil Productivity
These two terms are often confused but have an important distinction:
| Aspect | Soil Fertility | Soil Productivity |
|---|---|---|
| Definition | Inherent capacity to supply essential nutrients in adequate amounts | Capacity to produce a specific crop under defined management |
| Scope | Nutrient supply only | Includes fertility + physical + biological + management factors |
| Relationship | Fertile soil may not be productive (e.g., waterlogged fertile soil cannot grow wheat) | Productive soil is always fertile |
IMPORTANT
All productive soils are fertile, but not all fertile soils are productive. A soil may have abundant nutrients (fertile) but be waterlogged, saline, or poorly structured, making it unproductive. Productivity = Fertility + Water + Climate + Management + Variety.
Essential Plant Nutrients
A total of 17 elements are considered essential for plant growth, based on the criteria established by Arnon and Stout (1939).
Classification of Nutrients
| Category | Nutrients | Source |
|---|---|---|
| From air and water (3) | Carbon (C), Hydrogen (H), Oxygen (O) | CO₂, H₂O |
| Primary macronutrients (3) | Nitrogen (N), Phosphorus (P), Potassium (K) | Soil/Fertilizers |
| Secondary macronutrients (3) | Calcium (Ca), Magnesium (Mg), Sulphur (S) | Soil/Fertilizers |
| Micronutrients (8) | Iron (Fe), Manganese (Mn), Zinc (Zn), Copper (Cu), Boron (B), Molybdenum (Mo), Chlorine (Cl), Nickel (Ni) | Soil |
NOTE
C, H, and O together make up about 96% of plant dry matter and come free from air and water. The remaining 14 mineral nutrients (6 macro + 8 micro) come from the soil and must be managed through fertilization.
Criteria of Essentiality (Arnon and Stout, 1939)
An element is considered essential only if it meets all three criteria:
- Deficiency makes it impossible for the plant to complete its life cycle
- Deficiency is specific to the element and can only be corrected by supplying that element
- Element is directly involved in plant nutrition (not an indirect effect like improving soil structure)
Beneficial Elements
These are not essential but improve growth in specific crops:
- Silicon (Si) — strengthens stems in rice, reduces lodging and blast disease
- Sodium (Na) — beneficial for sugar beet and coconut
- Cobalt (Co) — essential for nitrogen-fixing bacteria in legume nodules
- Selenium (Se), Aluminium (Al) — beneficial in specific situations
Role of Major Nutrients
Nitrogen (N)
Nitrogen is the nutrient required in the largest quantity by most crops and is the most commonly deficient nutrient in Indian soils.
- Form absorbed: NH₄⁺ (ammonium) and NO₃⁻ (nitrate)
- Functions: Component of proteins, amino acids, chlorophyll, nucleic acids; promotes vegetative growth (green, leafy growth)
- Deficiency: General chlorosis (yellowing) of older/lower leaves first (N is mobile — plant moves it from old leaves to new growth); stunted growth; reduced tillering in cereals
- Excess: Excessive vegetative growth, delayed maturity, lodging (stems fall over), increased susceptibility to pests and diseases
- Content in plant: 1-5% of dry matter
TIP
Nitrogen deficiency appears in older leaves first because N is a mobile nutrient — the plant translocates it from old tissues to actively growing young tissues when supply is limited.
Phosphorus (P)
Phosphorus is critical for energy transfer and root development. It is the second most limiting nutrient after nitrogen in Indian soils.
- Form absorbed: H₂PO₄⁻ (primary orthophosphate) and HPO₄²⁻
- Functions: Component of ATP (energy currency), nucleic acids (DNA/RNA), phospholipids (cell membranes); promotes root development, flowering, seed formation
- Deficiency: Purple/reddish discolouration of older leaves (due to anthocyanin accumulation); stunted root growth; delayed maturity
- Content in plant: 0.1-0.4% of dry matter
Potassium (K)
Potassium is unique among macronutrients because it is NOT a structural component of any plant molecule — it remains in ionic form (K⁺) and functions as an activator and regulator.
- Form absorbed: K⁺
- Functions: Enzyme activation (activates 60+ enzymes), stomatal regulation (controls water loss), osmotic balance, disease resistance, improves quality of fruits
- Deficiency: Marginal scorching/browning of older leaf tips and edges; weak stalks prone to lodging
- Content in plant: 1-5% of dry matter
- Called the "quality nutrient" — improves taste, colour, shelf life, and disease resistance of produce
Secondary Macronutrients
| Nutrient | Form Absorbed | Key Function | Deficiency Symptom |
|---|---|---|---|
| Calcium (Ca) | Ca²⁺ | Cell wall formation, cell division, enzyme activation | Death of growing points (meristems); blossom-end rot in tomato |
| Magnesium (Mg) | Mg²⁺ | Central atom of chlorophyll molecule, enzyme activation | Interveinal chlorosis in older leaves (veins stay green, area between turns yellow) |
| Sulphur (S) | SO₄²⁻ | Component of amino acids (methionine, cysteine, cystine), vitamins (biotin, thiamine) | Uniform chlorosis of young leaves (unlike N, S is relatively immobile) |
NOTE
Magnesium is at the centre of every chlorophyll molecule. Without adequate Mg, plants cannot photosynthesize efficiently, leading to the characteristic interveinal chlorosis pattern.
Micronutrient Deficiency Symptoms
Although required in tiny amounts, micronutrient deficiencies can be devastating. Each micronutrient deficiency produces characteristic symptoms and often has specific crop associations that are frequently tested:
| Nutrient | Form Absorbed | Key Function | Deficiency Symptom | Sensitive Crop |
|---|---|---|---|---|
| Iron (Fe) | Fe²⁺, Fe³⁺ | Chlorophyll synthesis, electron transport | Interveinal chlorosis in young leaves | Rice (toxicity in waterlogged soils) |
| Zinc (Zn) | Zn²⁺ | Auxin synthesis (tryptophan → IAA), enzyme activation | Khaira disease in rice; little leaf; interveinal chlorosis | Rice, maize, citrus |
| Manganese (Mn) | Mn²⁺ | Photosynthesis (water splitting in PS-II), enzyme activation | Interveinal chlorosis with necrotic spots; grey speck in oats | Oats, wheat |
| Copper (Cu) | Cu²⁺ | Lignin synthesis, pollen viability | Reclamation disease; wilt of young leaves | Wheat, sunflower |
| Boron (B) | H₃BO₃ | Cell wall formation, pollen tube growth, sugar transport | Hollow stem in cauliflower; heart rot in beet; internal cork in apple | Cauliflower, beet |
| Molybdenum (Mo) | MoO₄²⁻ | Nitrate reductase enzyme, N₂ fixation in legumes | Whiptail in cauliflower; marginal scorch | Cauliflower, legumes |
| Chlorine (Cl) | Cl⁻ | Osmotic regulation, photolysis of water | Wilting; leaf chlorosis | Coconut |
| Nickel (Ni) | Ni²⁺ | Urease enzyme (breaks down urea in plant) | Leaf tip necrosis | Legumes |
Important Rules for Deficiency Symptoms
IMPORTANT
- Mobile nutrients (N, P, K, Mg): Deficiency appears in older/lower leaves first because the plant moves these nutrients from old tissues to new growth
- Immobile nutrients (Ca, S, Fe, Mn, Zn, Cu, B, Mo): Deficiency appears in young/upper leaves first because these nutrients cannot be redistributed within the plant
This rule is the single most useful tool for diagnosing nutrient deficiencies in the field.
Disease names and their deficient nutrients — Quick reference
- **Khaira disease** (rice) → Zinc (Zn) deficiency - **Grey speck** (oats) → Manganese (Mn) deficiency - **Reclamation disease** (cereals on reclaimed soils) → Copper (Cu) deficiency - **Whiptail** (cauliflower) → Molybdenum (Mo) deficiency - **Hollow stem** (cauliflower) → Boron (B) deficiency - **Heart rot** (sugar beet) → Boron (B) deficiency - **Blossom-end rot** (tomato) → Calcium (Ca) deficiency - **Internal cork** (apple) → Boron (B) deficiencyNitrogen Cycle
Nitrogen undergoes complex transformations in the soil-plant-atmosphere system. Understanding the N cycle is crucial for efficient fertilizer management because nitrogen is lost through multiple pathways.
Forms of Nitrogen in Soil
- Organic N (97–98% of total soil N) — locked in humus, proteins, amino acids; not directly available to plants
- Inorganic N (2–3%) — NH₄⁺ (ammonium), NO₃⁻ (nitrate), NO₂⁻ (nitrite) — the plant-available forms
- Most soil nitrogen is present in organic form, which must first be mineralized (converted to inorganic form) before plants can use it
Nitrogen Transformations
1. Ammonification (Mineralization)
Conversion of organic nitrogen → NH₄⁺ (ammonium)
Protein → Amino acids → NH₄⁺
- Done by heterotrophic bacteria and fungi
- Occurs in both aerobic and anaerobic conditions
- Also called nitrogen mineralization — this is the release of plant-available N from organic matter
2. Nitrification
Conversion of NH₄⁺ → NO₂⁻ → NO₃⁻ (a two-step oxidation process)
Step 1: 2NH₄⁺ + 3O₂ →(Nitrosomonas)→ 2NO₂⁻ + 2H₂O + 4H⁺
Step 2: 2NO₂⁻ + O₂ →(Nitrobacter)→ 2NO₃⁻
IMPORTANT
Key facts about nitrification:
- It is an oxidation process (requires O₂ — strictly aerobic)
- Nitrification decreases soil pH (H⁺ ions released in Step 1)
- Done by autotrophic bacteria: Nitrosomonas (Step 1) and Nitrobacter (Step 2)
- S.N. Winogradsky identified these nitrifying bacteria
3. Denitrification
Conversion of NO₃⁻ → NO₂⁻ → NO → N₂O → N₂ (gaseous loss back to atmosphere)
- It is a reduction process (removal of oxygen from nitrate)
- Occurs in waterlogged soils (anaerobic conditions)
- Done by anaerobic bacteria: Bacillus, Pseudomonas, Thiobacillus denitrificans
- Major pathway of nitrogen loss from paddy fields — this is why rice fields are notoriously inefficient at retaining nitrogen fertilizer
- Produces greenhouse gases (N₂O) contributing to climate change
4. Nitrogen Fixation
Conversion of atmospheric N₂ → NH₃/NH₄⁺ — the process that brings new nitrogen into the biological cycle.
| Type | Organism | Crop | N Fixed (kg/ha/yr) |
|---|---|---|---|
| Symbiotic | Rhizobium (root nodules) | Legumes | 50–200 |
| Associative | Azospirillum | Cereals (rice, wheat) | 20–40 |
| Free-living | Azotobacter | Non-legumes | 20–40 |
| Free-living | Blue-Green Algae (BGA) — Anabaena, Nostoc | Rice (wetland) | 20–30 |
| Symbiotic | Azolla + Anabaena azollae | Rice | 40–60 |
TIP
Rhizobium is the most important nitrogen fixer in agriculture and is host-specific — each legume requires a specific strain. Azotobacter is the most important free-living fixer for non-legume crops.
5. Immobilization (Fixation)
Conversion of inorganic nitrogen (NH₄⁺, NO₃⁻) → organic nitrogen — the reverse of mineralization.
- Occurs when C:N ratio of added material is high (> 25:1) — microbes need nitrogen to decompose carbon-rich material, so they "lock up" soil N
- This is temporary — as decomposition proceeds and C:N ratio drops, the immobilized N is eventually released
6. Volatilization
NH₄⁺ → NH₃ (gas) — Loss of nitrogen as ammonia gas to the atmosphere.
- Occurs in alkaline soils (pH > 7.5)
- Major loss pathway when urea is broadcast on soil surface without incorporation — the urease enzyme converts urea to ammonium carbonate, which decomposes to NH₃ gas
- Can be reduced by: deep placement, neem coating, irrigation after application
Phosphorus in Soil
Forms of Phosphorus
- Organic P — 20–80% of total soil P (in phytin, nucleic acids, phospholipids)
- Inorganic P — Mineral form; primary source: Apatite Ca₁₀(PO₄)₆(F,Cl,OH)₂
- Plants absorb P as H₂PO₄⁻ (primary orthophosphate, dominant at pH < 6.5) and HPO₄²⁻ (at alkaline pH)
Phosphorus Fixation (Why P is Unavailable)
Phosphorus is the most "fixed" nutrient in soil — most of the applied P becomes unavailable to plants:
| Soil Condition | Fixation By | Result |
|---|---|---|
| Acidic soils (pH < 6.0) | Fe and Al oxides | Fe-P and Al-P (insoluble) |
| Alkaline soils (pH > 7.5) | Calcium | Ca-P (insoluble) |
| Neutral pH (6.0–7.5) | — | Maximum P availability |
WARNING
Only 15–25% of applied P is actually used by crops in the year of application — the rest gets fixed. This is why placement (band application near roots) is recommended over broadcasting for P fertilizers, as it reduces contact with soil particles that fix P.
Potassium in Soil
Forms of Potassium
Potassium exists in four forms in soil, with vastly different availability to plants:
| Form | Availability | % of Total K |
|---|---|---|
| Water-soluble K | Immediately available | < 1% |
| Exchangeable K | Readily available | 1–2% |
| Non-exchangeable (fixed) K | Slowly available (released over months/years) | 1–10% |
| Mineral (lattice) K | Unavailable (locked in mineral structure) | 90–98% |
NOTE
Although 90-98% of soil K is locked in mineral form, there is a dynamic equilibrium between the four forms. As plants remove water-soluble K, exchangeable K replenishes it, which in turn is slowly replenished by non-exchangeable K. This is why many Indian soils can sustain crops without K fertilization for years — but eventually, K depletion occurs.
- K is NOT a structural component of plants — remains in ionic form
- K is called the "quality nutrient" — improves disease resistance, drought tolerance, and fruit quality
Soil pH and Nutrient Availability
Effect of pH on Nutrient Availability
pH is the master variable of soil chemistry because it controls the availability of almost every nutrient:
| pH Range | Nutrients Most Available |
|---|---|
| Acidic (pH < 6.5) | Fe²⁺, Mn²⁺, Cu²⁺, Zn²⁺ (micronutrients — high availability, may cause toxicity) |
| Neutral (pH 6.5–7.5) | N, P, K, Ca, Mg, S — maximum availability of most nutrients |
| Alkaline (pH > 7.5) | Mo (available); Fe, Mn, Zn, Cu, B (low availability → deficiency) |
IMPORTANT
- Phosphorus availability is maximum at pH 6.0–7.5 (the narrow "sweet spot")
- Molybdenum is the only micronutrient whose availability increases with increasing pH — all other micronutrients become less available as pH rises
- Fe, Mn, Cu, Zn become more available at low pH (acidic conditions) — this can cause toxicity in very acidic soils
Acidic Soils (pH < 7)
- H⁺ and Al³⁺ ions are dominant on the exchange complex
- Area in India: ~90 million hectares; highest in West Bengal
- Found in humid climate regions where bases (Ca, Mg, K) are leached by heavy rainfall
- Fe, Mn, Cu, Zn availability — high (may cause toxicity)
- Ca, Mg, K, Na availability — low (leached away)
- Organic matter — high (slow decomposition in acidic conditions)
Types of soil acidity:
- Active acidity — Due to H⁺ and Al³⁺ in soil solution; measured by pH meter
- Reserve/Exchange acidity — Due to H⁺ and Al³⁺ on the exchange complex (clay/humus surfaces); much larger than active acidity
- Total acidity = Active + Reserve acidity
Factors causing soil acidity:
- Parent material (acidic rocks like granite produce acidic soils)
- Use of acidic fertilizers (ammonium sulphate, urea, DAP, NH₄Cl — nitrification releases H⁺)
- Humid climate (high rainfall leaches bases Ca, Mg, K from soil)
- Organic matter decomposition → organic acids formed
- Acid rain (SO₂ + NO₂ in atmosphere → H₂SO₄ and HNO₃)
Liming of Acidic Soils
Lime materials used to correct acidity:
| Material | Formula |
|---|---|
| Limestone | CaCO₃ |
| Dolomite | CaCO₃·MgCO₃ |
| Burnt lime / Quick lime | CaO |
| Hydrated/Slaked lime | Ca(OH)₂ |
| Chalk | CaCO₃ (soft) |
| Marl | CaCO₃ (soft) |
Changes when lime is added: pH increases, H⁺ decreases, OH⁻ increases, Ca/Mg/K/Na availability increases, Fe/Mn/Cu/Zn availability decreases (which can be beneficial when these are at toxic levels).
Basic fertilizers (suitable for acidic soils): Sodium nitrate, Calcium nitrate, Potassium nitrate, Rock phosphate
Alkaline/Sodic Soils
Classification of salt-affected soils — this table distinguishes three types based on EC, pH, and ESP:
| Parameter | Saline | Sodic (Alkali) | Saline-Sodic |
|---|---|---|---|
| EC (dS/m) | > 4 | < 4 | > 4 |
| pH | < 8.5 | > 8.5 | > 8.5 |
| ESP | < 15 | > 15 | > 15 |
| Physical condition | Good (flocculated) | Poor (dispersed) | Poor |
| Dominant cation | Ca, Mg | Na | Na |
TIP
Saline soils have good structure (salts promote flocculation) but excess salts. Sodic soils have poor structure (Na⁺ causes deflocculation) and high pH. The reclamation approaches are therefore different: leaching for saline soils, gypsum + leaching for sodic soils.
Gypsum Requirement (G.R.):
G.R. = (ESP initial − ESP final) / 100 × CEC
- Gypsum (CaSO₄·2H₂O): Ca = 23.1%, S = 18.6%
- Ca²⁺ from gypsum replaces Na⁺ on clay surfaces → improves structure through flocculation
- Leaching with good quality water is essential after gypsum application to wash the displaced Na⁺ out of the root zone
Summary Cheat Sheet
| Concept / Topic | Key Details / Explanation |
|---|---|
| Soil Fertility vs Productivity | Fertility = nutrient supply only; Productivity = fertility + physical + biological + management; all productive soils are fertile, but not all fertile soils are productive |
| Essential elements | 17 total: 3 from air/water (C, H, O) + 3 primary macro (N, P, K) + 3 secondary macro (Ca, Mg, S) + 8 micro (Fe, Mn, Zn, Cu, B, Mo, Cl, Ni) |
| C, H, O contribution | ~96% of plant dry matter; from CO₂ and H₂O |
| Essentiality criteria | Arnon and Stout (1939): deficiency prevents life cycle completion; specific to that element; directly involved in nutrition |
| Beneficial elements | Si (rice — reduces lodging/blast), Na (sugar beet), Co (N-fixing bacteria in legumes) |
| Nitrogen (N) | Absorbed as NH₄⁺ and NO₃⁻; component of proteins, chlorophyll, nucleic acids; deficiency: chlorosis in older leaves (mobile nutrient); excess: lodging |
| Phosphorus (P) | Absorbed as H₂PO₄⁻; component of ATP, DNA, cell membranes; promotes root development, flowering; deficiency: purple/reddish older leaves |
| Potassium (K) | Absorbed as K⁺; NOT structural — ionic form; activates 60+ enzymes; stomatal regulation; called "quality nutrient"; deficiency: marginal scorching of older leaf tips |
| Calcium (Ca) | Cell wall formation, cell division; deficiency: death of growing points; blossom-end rot in tomato |
| Magnesium (Mg) | Central atom of chlorophyll; deficiency: interveinal chlorosis in older leaves |
| Sulphur (S) | Component of amino acids (methionine, cysteine, cystine); deficiency: uniform chlorosis of young leaves (immobile) |
| Mobile nutrients | N, P, K, Mg — deficiency in older/lower leaves first |
| Immobile nutrients | Ca, S, Fe, Mn, Zn, Cu, B, Mo — deficiency in young/upper leaves first |
| Khaira disease (rice) | Zinc (Zn) deficiency |
| Grey speck (oats) | Manganese (Mn) deficiency |
| Reclamation disease | Copper (Cu) deficiency |
| Whiptail (cauliflower) | Molybdenum (Mo) deficiency |
| Hollow stem (cauliflower) | Boron (B) deficiency |
| Heart rot (sugar beet) | Boron (B) deficiency |
| Blossom-end rot (tomato) | Calcium (Ca) deficiency |
| Organic N in soil | 97-98% of total soil N; must be mineralized before plant use |
| Ammonification | Organic N → NH₄⁺; by heterotrophic bacteria; aerobic + anaerobic |
| Nitrification | NH₄⁺ → NO₂⁻ → NO₃⁻; oxidation (aerobic); by Nitrosomonas (Step 1) + Nitrobacter (Step 2); decreases soil pH |
| S.N. Winogradsky | Identified nitrifying bacteria |
| Denitrification | NO₃⁻ → N₂ (gas loss); reduction; in waterlogged/anaerobic soils; by Bacillus, Pseudomonas; major N loss from paddy |
| N₂ Fixation — Symbiotic | Rhizobium (legumes, 50-200 kg N/ha); Azolla + Anabaena (rice, 40-60 kg) |
| N₂ Fixation — Free-living | Azotobacter (non-legumes, 20-40 kg); BGA (rice, 20-30 kg) |
| N₂ Fixation — Associative | Azospirillum (cereals, 20-40 kg) |
| Immobilization | Inorganic N → organic N; occurs when C:N > 25:1 (temporary N lockup) |
| Volatilization | NH₄⁺ → NH₃ gas; in alkaline soils (pH > 7.5); major loss from surface-broadcast urea |
| P fixation — Acidic soils | Fixed by Fe and Al oxides → insoluble Fe-P, Al-P |
| P fixation — Alkaline soils | Fixed by Calcium → insoluble Ca-P |
| P maximum availability | At pH 6.0-7.5 (neutral range) |
| P use efficiency | Only 15-25% in year of application; band placement recommended |
| K forms in soil | Water-soluble (<1%) → Exchangeable (1-2%) → Non-exchangeable (1-10%) → Mineral/lattice (90-98%) |
| Molybdenum — unique | Only micronutrient whose availability increases with increasing pH |
| Micronutrients at low pH | Fe, Mn, Cu, Zn — more available (may cause toxicity) |
| Acidic soils in India | ~90 million ha; highest in West Bengal |
| Liming materials | CaCO₃ (limestone), CaCO₃·MgCO₃ (dolomite), CaO (burnt lime), Ca(OH)₂ (slaked lime) |
| Saline soil | EC > 4 dS/m; pH < 8.5; ESP < 15; good structure; dominant cation: Ca, Mg |
| Sodic soil | EC < 4; pH > 8.5; ESP > 15; poor structure (Na⁺ disperses); dominant: Na |
| Saline soil reclamation | Leaching with good quality water + drainage |
| Sodic soil reclamation | Gypsum (Ca²⁺ replaces Na⁺) + leaching |
| Gypsum composition | Ca = 23.1%, S = 18.6% |
Lesson Doubts
Ask questions, get expert answers