Soil Science Important Points
Sub. Soil Science
Exam Oriented Points
1.Causes Of Soil Colours
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| Soil Colours | Causes Of Soil Colours |
| Black colour | Organic matter (O.M.) |
| Red yellow | Unhydrated ferric oxides. |
| Brown | Mixture of O.M and Iron oxides. |
| White | Silica and lime |
| Bluish and Greenish | Ferrous compound |
| Motting colour | Alternate oxidation and reduction of iron |
2. Elemental Composition Of Humus
AgriExam.com
| Elements | Percentage |
| Carbon | 55 to 60% |
| Nitrogen | 5 to 6 % |
| Hydrogen | 4-5% |
| Oxygen | 35-40 % |
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3. Tolerance of plants to Boron
| Tolerant | Semi Tolerant | Sensitive |
| Sugar-beet, Onion, Turnip, Cabbage, Lettuce, Carrot. | Sunflower, Potato, Tomato, Radish, Wheat, Corn, Beans. | Apple, Grape, Fig, Cherry, Apricot, Orange, Lemon. |
4. Elements & Scientist discovered
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| Element | Scientist discovered |
| Oxygen | De sausser (1804) |
| Nitrogen | Ruther Ford (1672) |
| Phosphorus | C. Springel (1939) |
| Potassium | Schimper (1890) |
| Calcium | Solm-Harstmar |
| Magnesium | C Springel (1839) |
| Sulphur | C Springel (1839) |
| Iron | E. Griss (1844) |
| Manganese | MC Hargue (1922) |
| Zinc | Sommer & Lipman |
| Copper | Sommer & Lipman 1931 |
| Boron | K. Warington (1923) |
| Molybdenum | Arnon & Stout (1939) |
| Chlorine | Boyer Corton & Johnsen |
| Nickel | AH Brown & R.M.Welson |
5. Factors of soil formation
| Factors of soil formation AgriExam.com | |
| S =F (CI, O, r, p, t,…) | |
| S | Soil Formation |
| O | Organism |
| t | time |
| F | Function |
| Cl | Climate |
| r | Relief or topography |
| P | parent material |
6. Classification of Rocks
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| According To Their Origin / Mode of Formation | |
| 1. Igneous Rock Classified On The Basis Of Chemical Composition. | |
| Rocks | Example |
| Acid rocks | Granite, Rhyolite. |
| Sub Acid Rocks | Syenite and Trachika |
| Sub basic rocks | Andesite. |
| Basic Rocks | Gabbro and Basalt |
| Ultra Basic Rock | Limestone |
| 2. Sedimentary Rock | |
| Aranaceous | Sandstone |
| Agrillaceous | Mudstone |
| Calcareous | Limestone |
| Carbonaceous | Calpet |
| Silicious | Diatomecious |
| Precipited | Gypsum |
| 3. Metamorphic Rock | |
| Hydro metamorphic rocks | Quartzite, Laterite. |
| Dynamo metamorphic rocks | Schist, Gnesis. |
| By heat (Thermometamorphic) | Marble |
7. Igneous Rock Classified On The Basis Of Chemical Composition.
AgriExam.com
| Igneous Rock | Silica % |
| Acid rocks | > 65% |
| Sub Acid Rocks | 60-65% |
| Sub basic rocks Contains | 55-60% |
| Basic Rocks | 45-55% |
| Ultra Basic Rock | < 50-45 % |
Soil Science Important Points
| Soil Science Important Table – 1 | Cl;ick |
| Soil Science Important Table – 2 | Cl;ick |
| Soil Science Important Table – 3 | Cl;ick |
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