Soil Science Important Points (1)

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Soil Science Important Points

Soil Science Important Points (1)

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.
  • Pis 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 10
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

24 thoughts on “Soil Science Important Points (1)”

  1. Good Content It’s very useful apps for agriculture students for preparation any competitive exams

    Reply
  2. Small correction:- pF value at Hygroscopic coefficient should be 4.50. For Air dry soil it is 6 (pF) 1000 (atm).

    Reply
  3. Really u people making us study without any trouble by providing study materials and important current affairs… There is no need to buy books for preparation.. Tq so much..

    Reply
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