Soil Science Important Points
Exam Oriented Points
1.General Recommended Fertilizer Doses (N:P:K Ratio)
| Cereal crops | 4:2:1 |
| Pulses crops | 1:2:1 or 1:2:2 |
| Oil seed crops | 3:2:1 |
| Fodder/Fibers crops | 2:1:4 |
| Root crops | 2:1:1 |
2.Classification Of Irrigation Projects
CCA: – Culturable Commend Area
| Project | CCA (ha) | Cost (Rs) |
| Major | >10,000 | >50 Crores |
| Medium | 2000-10,000 | 5 Crores to 25 Lacs |
| Minor | <2000 | <25 Lacs |
3.Composition of atmospheric air
| Gases | Volume % |
| Nitrogen | 78.08 |
| Oxygen | 20.95 |
| Argon | 0.93 |
| Carbon dioxide | 0.03 |
4.Character of Saline & Alkaline Soil
| Character | Saline Soil | Alkaline Soil | Saline-Alkaline |
| ESP | <15% | >15% | >15% |
| EC(dSm) at 25°C | >4% | <4% | >4% |
| pH | <8.5 | >8.5 | >8.5 |
ESP = Exchangable sodium percentage
EC = Electricity conductivity
pH = power of hydrogen
5.Pf value
- P means potenz its meaning power at 10.
- Pf is the scale like pH through which we measure the force with which water is retained in capillary or soil
| Soil condition | Pressure (atm/bars) | Pf value |
| Saturated soil | 0.001 | 0 |
| Field capacity | 1/3 | 2.53 |
| PWP | 15 | 4.18 |
| Hygroscopic point | 31 | 4.5 |
| Oven dry soil | 10,000 | 7 |
PWP = Permanent wilting Point
6.Measurement of irrigation water:
| 1 Cusec | 28.3 liters |
| 1 Cumec | 1000 liters or 103 |
| 1 ha mm | 10,000 liters 104 |
| 1 ha cm | 100,000 liters or 105 |
| 1 ha m | 100,000,00 liters or 107 |
7.Carbon Nitrogen (C:N) Ratio
| C:N Ratio of Material | C:N Ratio |
| Humus | 10:1 |
| Normal soils | 8:1 to 15:1 |
| Legumes | 20:1 to 30:1 |
| Cereals | 90:1 |
| FYM | 25:1 to 30:1 |
| Sawdust | 400:1 (Highest) |
| Micro-organism | 4:1 to 9:1 (Lowest) |
8.Equivalent Acidity of Fertilizers
Equivalent Acidity: The amount of CaCO3 required to neutralise the acid residues caused by acidic fertilizers in the soil e.g. 100 kg (NH4)2SO4 produces acidity which needs 110 kg of CaCO3 to neutralist it. Therefore equivalent acidity of (NH4)2SO4 is 110; Anhydrous NH3 has more equivalent acidity than other fertilizers.
| Fertilizers | Equivalent Acidity |
| Anhydrous ammonia | 148 (Highest) |
| Ammoniunm chloride (NH4CI) | 128 |
| Ammonium sulphate (NH4)2SO4 | 110 |
| Ammonium sulphate nitrate (NH4)2SO4NH4NO3 | 93 |
| Urea | 80 – 85 |
| DAP | 77 |
| Ammonium nitrate (NH4NO3) | 60 |
| Mono-ammonium Phosphate | 55 (Lowest) |
9.Equivalent Basicity of Fertilizers
Equivalent Basicity: Residual basicity caused by application of basic fertilizers, expressed in terms of CaCO3 equivalent of basic residues left by a fertilizer material (in kg/100 kg of fertilizer salt).
| Fertilizers | Equivalent basicity |
| Calcium cyanamide (CaCN2) | 63 |
| Sodium nitrate (NaNO3) | 29 |
| Potassium nitrate (KNO3) | 29 |
| Nitrate of Soda Potash | 26 |
| Calcium nitrate Ca(NO3) | 21 |
10.Plants used for nutrient deficiency indicator
| Nutrients | Indicator plant |
| Nitrogen | Cauliflower, Cabbage |
| Phosphorus | Mustard, Rapeseed |
| Potassium | Potato |
| Calcium | Cauliflower, Cabbage |
| Boron | Sunflower, Sugar-beet |
| Sodium | Sugar beet, Turnip |
| Chlorine | Lettuce |
| Ferrous | Sorghum, Citrus, Barley |
| Copper | Wheat |
| Magnesium | Potato, Cauliflower, Sugar beet |
| Manganese | Sugar beet, Apple, Apricot |
| Molybdenum | Cauliflower |
| Zinc | Maize |
11.Sources of plant nutrients
| Nutrients | Sources |
| Nitrogen (N) | Organic Matter |
| Phosphorus (P) | Appetite |
| Potassium (K) | Biotite, Orthoclase |
| Calcium (Ca) | Anorthite, Dolomite |
| Magnesium(Mg) | Dolomite, Olivine |
| Manganese (Mn) | Pyrolusite |
| Ferrous (Fe) | Pyrite |
| Boron(B) | Tourmaline |
| Molybdenum (Mo) | Olivine |
.Note:- More important soil Science Table Upload Soon
| Important Table – 1 | Cl;ick |
| Important Table – 2 | Cl;ick |
| One Liner | Cl;ick |
| Fertilizers classification | Cl;ick |
Soil Science Important Points
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Small correction:- pF value at Hygroscopic coefficient should be 4.50. For Air dry soil it is 6 (pF) 1000 (atm).
Yupp
Very helpful Sir thank you so much sir
Sir yeh Hygroscopic soil ka jo hai wo 4.5 pf hoga
Sir table 4 plz check it
Ph of saline akline soilis
<,8.5
very important
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