Category: Soil Science Tables
Soil types
By Agritests |
21 Jun, 2026
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Alfisols: Relatively young, acidic soils often found under forest vegetation. Andisols: Soils formed from volcanic ash, fertile and well-drained.Aridisols: Soils typical of desert or arid regions with low moisture content.Entisols: Recently deposited alluvial soils, often found in river plains.Histosols: Organic-rich soils, commonly known as peat or muck soils.Inceptisols: Young soils with minimal horizon development.Mollisols: Fertile prairie soils rich in organic matter.Oxisols: Highly weathered, […]
Soil–Water–Irrigation Concepts & Scientists
By Agritests |
20 Jun, 2026
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Concept / Term Scientist(s) Year Key Contribution Soil Water Classification Briggs 1894 Gravitational, capillary & hygroscopic water Moisture Holding Capacity Hilgard 1896 Water retention against gravity Capillary Potential Buckingham 1907 Capillary movement in unsaturated soils Moisture Equivalent Briggs & McLane 1910 Water retained after centrifugation Permanent Wilting Point (PWP) Briggs & Shantz 1912 Plant cannot […]
Different Nutrient Test Methods in Soil
By Agritests |
20 Jun, 2026
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🧪 Different Nutrient Test Methods in Soil Nutrient Determination Analyzing / Test Method Total Nitrogen in Soil Kjeldahl Process Available Nitrogen (N) Alkaline Permanganate Method Phosphorus (Acidic Soil) Bray No. 1 Method Phosphorus (Neutral & Alkaline Soil) Olsen’s Method Potassium (K) & Sodium (Na) Flame Photometer Sulphate Sulphur (SO₄²⁻) Turbidimetric Method Organic Carbon a) Walkley […]
Soil Test Rating Chart for Available Nutrients
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20 Jun, 2026
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🧪 Soil Test Rating Chart for Available Nutrients Nutrient Low Level Medium Level High Level Nitrogen (N) < 250 kg/ha 250 – 500 kg/ha > 500 kg/ha Phosphorus (P) < 20 kg/ha 20 – 50 kg/ha > 50 kg/ha Potassium (K) < 125 kg/ha 125 – 300 kg/ha > 300 kg/ha Zinc / Copper (Zn […]
Soil Orders and their characteristics
By Agritests |
20 Jun, 2026
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🌍 Soil Orders and Their Key Characteristics Soil Order Key Characteristics Alfisols Relatively young, acidic soils often found under forest vegetation. Andisols Soils formed from volcanic ash, fertile and well-drained. Aridisols Soils typical of desert or arid regions with low moisture content. Entisols Recently deposited alluvial soils, often found in river plains. Histosols Organic-rich soils, […]
Important Conversion Factors (Soil & Plant Nutrition)
By Agritests |
20 Jun, 2026
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🔁 Important Conversion Factors (Soil & Plant Nutrition) From To Conversion Factor Nitrate (NO₃) Nitrogen (N) NO₃ × 0.22 Nitrogen (N) Nitrate (NO₃) N × 4.54 Phosphorus (P) P₂O₅ P × 2.27 P₂O₅ Phosphorus (P) P₂O₅ × 0.44 Potassium (K) K₂O K × 1.20 K₂O Potassium (K) K₂O × 0.83 Calcium (Ca) CaO Ca × […]
Cation Exchange Capacity (CEC) of Soils
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20 Jun, 2026
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⚖️ Cation Exchange Capacity (CEC) of Soils Soil Texture CEC (meq / 100 g) Sand (light colour) 3 – 5 Sand (dark colour) 10 – 20 Loam 10 – 15 Silt loam 15 – 25 Clay & Clay loam 20 – 50 Organic soil 50 – 100
Soil Classification Based on pH
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20 Jun, 2026
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🧪 Soil Classification Based on pH Soil Reaction Class pH Range Extremely acidic < 4.5 Moderately acidic 4.5 – 5.5 Slightly acidic 5.5 – 6.5 Neutral 6.5 – 7.5 Slightly alkaline 7.5 – 8.5 Moderately alkaline 8.5 – 9.5 Extremely alkaline > 9.5
Classification of Soil Particle Size
By Agritests |
20 Jun, 2026
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🧪 Classification of Soil Particle Size Soil Separate IISS Diameter (mm) USDA Diameter (mm) Gravel > 2.0 > 2.0 Coarse Sand 0.2 – 2.0 0.5 – 1.0 Fine Sand 0.02 – 0.2 0.1 – 0.25 Silt 0.002 – 0.02 0.002 – 0.05 Clay < 0.002 < 0.002
Important Events in Soil–Water Relationship
By Agritests |
20 Jun, 2026
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S. No. Scientific Contribution / Event Associated Scientist(s) & Year 1 Classification of soil water Briggs (1894) 2 Moisture holding capacity Hilgard (1896) 3 Capillary potential Buckingham (1907) 4 Moisture equivalent Briggs & McLane (1910) 5 Permanent wilting point (PWP) Briggs & Shantz (1912) 6 Hygroscopic coefficient Alway (1913) 7 Field capacity (FC) Israelsen & […]