FERTILIZER RECOMMENDATION BASED ON SOIL TEST VALUES
1.
2. FERTILIZER RECOMMENDATION BASED
ON SOIL TEST VALUES
PRESENTED BY
YALLANAGOUDA B M
UG13AGR1916
UNIVERSITY OF AGRICULTURAL SCIENCES,RAICHUR
COLLEGE OF AGRICULTURE, KALABURAGI
3. Soil
Soil is one of the most important natural
resource and play a major role in crop
production
Soil testing is the base for management
decisions about fertilizer requirements
Helps to prepare soil fertility map
Areas of sufficient and insufficient nutrients
are marked out and nutritional requirements
are determined
4. Fertilizers such as NPK, lime or gypsum are
recommended to improve soil fertility
Fertilizer addition, which is based on soil
testing, usually leads to an increase in yields
and profits by providing the correct amounts
of needed nutrients
It also leads to uniform application of
nutrients in a field.
Regular soil testing also contributes to
environmental sustainability as the use of
excess fertilizers can be avoided
8. Mineral nutrient Nutrient mobility
within plant
Plant organ where deficiency
symptoms appear
N, P, K, Mg High Old leaves
S Low Young leaves
Fe, Zn, Cu, Mo Very low Young leaves
B, Ca Extremely low Young leaves and terminal
Mobility of nutrients in plant
9. Mobility of nutrients in
soil
Mobile Less mobile Immobile
Nitrate
(mass flow)
Ammonia
( mass flow)
Phosphorus
(diffusion)
Sulphur
(mass flow)
Potassium
(diffusion)
Zinc (diffusion)
Boron
(mass flow)
Calcium (root
contact)
Chloride
(mass flow)
Magnesium
(root cot act)
Manganese
(diffusion)
Copper
(diffusion)
12. Element & Symbol Ion or Molecule Functions
Primary macro nutrients
Nitrogen (N) NH4
+ (ammonium)
NO3
- (nitrate)
Synthesis of Proteins,but
structurally it is also a part of the
chlorophyll molecule.
Many proteins are enzymes.
Synthesis of nucleic acids, early
root growth , energy
transformation, fruiting &
seeding.
Carbohydrate metabolism,
enzyme activation, efficient use
of water, nitrogen uptake and
protein synthesis and
translocation of
Sugars(assimilates), early
maturity, resistance against insect
and diseases and in improving
quality.
Phosphorous (P) H2PO4
2-
HPO4 (phosphates)
Potassium (K) K+
13. Secondary macro nutrients
Calcium (Ca) Ca2+ Cell-wall, good root system. It protects
the entery of pathogens into the cell
wall.
Essential component of the chlorophyll
molecule and sugar translocation.
Protein synthesis and in Oil formation.
Magnesium (Mg) Mg2+
Sulphur (S) SO4
2-
Micronutrients (trace elements)
Zinc (Zn) Zn2+ Involved in the activation of various
enzyme systems (Enzyme : It is made
up of amino acids (protein) and it helps
in the conversion of organic and
inorganic nutrients into available forms
without changing itself. Synthesis of
chlorophyll.
Iron (Fe) Fe2+ (ferrous)
Manganese (Mn) Mn2+
Molybdenum (MO) MoO4
2-
Copper (Cu) Cu2+
Boron (B0) H3BO3 (boric acid) Translocation of sugars
Sodium (Na+) and
Chlorine (Cl-)
Na+ and Cl-
(Chloride)
Electrolytes necessary for osmotic
pressure and acid-base balance and
activates the oxygen producing enzyme
of photosynthesis.
14. Other
Carbon (C) CO2 (mostly through leaves)
Hydrogen (H) HOH (hydrogen from water), H+
Oxygen (O) CO2 (mostly through leaves),H2O,O2
Few additional elements
Cobalt (CO) CO2+ : Legumes
Nickel (Ni) Ni2+ : -
Silicon (Si) Si (OH)4 (non-ionized) : Paddy (Silicon contributes
to the structure of cell walls, thereby imparting greater
disease resistance, stalk strength, and resistance to
lodging.
Sodium(Na) Na+ : Sugarbeet
Vanadium (V) VO3
- : Algae
15. Nutrient use efficiency in India
Nutrient Efficiency (%)
Nitrogen 30-50
Phosphorus 15-20
Potassium 70-80
Zinc 2-5
Iron 1-2
Copper 1-2
16. Effect of pH on Nutrient Availability
Ideal pH for maximum Nutrient Availability is 6.5- 7.5
22. Advantages of soil testing
• Helps to take advantage of nutrients already in
the soil
• To know the characteristics and fertility status of
soil
• Soil fertility status helps in selection suitable
and economical crops for specific fields and
farming situations
• Helps to Know the soil pH, EC, Organic carbon,
available nitrogen, phosphorous, potassium,
secondary and micronutrients present in the
soil
23. Advantages of soil testing
• Lime requirement of soils
• Gypsum requirement of soils
• Helps in making fertilizer recommendations
for specific crops and cropping systems
• Reduce fertilizer applications by applying
only what is needed
• Maximizes yield and lowers the cost towards
fertilizer
24. Methods of analysis of soil sample
Properties Extractant
Soil /
Extractant
ratio
Shakin
g time
Method
pH Distilled water 1:2.5 30 Potentiometric method
EC Distilled water 1:2.5 30 Conductometric method
Organic Carbon Walkley & Black’s
method
Avail. Nitrogen (N) Alkaline potassium
permanganate method
Avail. P2O5
Bray’s
extractant for
acid soils
Olsen’s
extractant for
neutral &
alkaline soils
1:10 for
Bray’s
Method (5 g
soil : 50 ml )
1:20 for
Olsen’s
method (2.5
g soil : 50 ml )
5
30
Colorimetric method
Colorimetric method
Avail. K2O N N Ammonium
acetate
1:5 (5 g soil
:25 ml)
5 Flame photometric
method
25. Analysis of secondary nutrients
Nutrients Extractant
Soil /
Extractant
ratio
Shaking
time
Method
Avail. Ca N N
Ammonium
acetate
1:5 (10 g
soil : 50
ml)
5 min
EDTA Titration
method
Avail. Mg N N
Ammonium
acetate
1:5 (10 g
soil : 50
ml)
5 min
EDTA Titration
method
Avail. S Mono Calcium
Phosphate/
0.15% CaCl2
1:2.5 (10 g
soil : 25
ml)
30 min
Turbid metric
method
26. Soil analysis for micronutrients
• Available iron (Fe)
• Available Manganese (Mn)
• Available Zinc (Zn)
• Available Copper (Cu)
• Available Boron (B) – Hot water (1:2 ratio & 5 minutes
boiling) and Azomethan-H method
• Available Molybdenum (Mo) – Ammonium oxalate extractant
(1:10 ratio & 10 hours shaking) and Colorimetric or AAS
• Available Chlorine (Cl) – water(1:5 ratio & 5 min) and Mohr’s
titration method
DTPA extractant (1:2 soil to extractant
ratio & 2 hrs shaking) & Atomic
absorption spectrophotometer (AAS)
27. Lime & Gypsum requirement of soils
• Lime requirement of an acid soil (pH < 6.5) is
determined by Shoemaker’s method
• Gypsum requirement of an alkali/ saline–alkali soils
using saturated solution of gypsum & EDTA method
29. Electrical conductivity (EC)
EC values Interpretation
< 1 dS m-1 at 250 C Normal soil with respect to
soluble salts
1- 2 dS m-1 at 250 C Critical to crop growth
> 2 dS m-1 at 250 C Injurious to crops
32. Interpretation of micronutrients results
Micronutrient Extractant
Critical level in soil
(mg /kg)
Iron (Fe) DTPA 2.5-4.5
Manganese (Mn) DTPA 2.0 -3.0
Zinc (Zn) DTPA 0.6 – 1.2
Copper (Cu) DTPA 0.2-0.5
Boron (B) Hot water 0.33-1.0
Molybdenum
(Mo)
Ammonium
oxalate
0.04
33. N - fertilizers recommendation based on soil test results
Recommended
dose of N fertilizers
Low available N
status in soil
High N status in soil
< 50 kg ha-1 No change in the recommendation
51 - 100 kg ha-1 + 12.5 kg ha-1 - 12.5 kg ha-1
100 - 175 kg ha-1 + 25.0 kg ha-1 - 25.0 kg ha-1
175 - 250 kg ha-1 + 37.5 kg ha-1 - 37.5 kg ha-1
251 - 325 kg ha-1 + 50.0 kg ha-1 - 50.0 kg ha-1
For medium N status of soil – No modification in the fertilizers recommended
34. P & K fertilizers recommendations
based on the soil test results
Recommended P or K
fertilizers
Low status of P or K
in soil
High status of P or
K in soil
Phosphorus
<25 kg P2O5ha-1 No change in the recommendation
26 – 75 kg P2O5ha-1 + 12.5 kg P2O5ha-1 - 12.5 kg P2O5ha-1
> 75 kg P2O5ha-1 + 25.0 kg P2O5ha-1 - 25.0 kg P2O5ha-1
Potassium
<25 kg K2O ha-1 No change in the recommendation
26 – 50 kg K2O ha-1 + 12.5 kg K2O ha-1 - 12.5 kg K2O ha-1
51 – 100 kg K2O ha-1 + 25.0 kg K2O ha-1 - 25.0 kg K2O ha-1
101 - 175 kg K2O ha-1 + 37.5 kg K2O ha-1 - 37.5 kg K2O ha-1
35. For example:
pH 8.20
EC (dS/m at 250 C) 0.20
OC (%) 0.40
Avail. N (kg ha-1) 180
Avail. P2O5 (kg ha-1) 59.0
Avail. K2O (kg ha-1) 400
Soil test results
•Farmer wants to grow Pigeonpea & the
recommended dose of NPK for
Redgram is
25: 50: 0 kg, N2:P2O5:K2O /ha
Therefore modified recommendation
based on soil test values is
25:37.5:0 kg, N2:P2O5:K2O /ha
Therefore, apply 22 kg of Urea and 94 kg of
Single Superphosphate per acre
37. IPNMS for Desired Yield
• Balanced Fertilization
• Reverse the ill Effect of Soil Mining of Nutrients
• Promoting Tenets of Sustainable Agriculture
• Response of Fertilizers Declining due to
• Sub-optimal and Imbalance in Fertilizer Use
38. IPNMS for Desired Yield
• Inappropriate Methods and Time of
Application
• Lesser Use of Organic Manure
• IPNMS Must for the Desired Results
• IPNMS for Desired Yield
39. The Key Objectives of IPNMS
• To maintain or enhance soil productivity through balanced
use of fertilizers combined with organic and biological
sources of plant nutrients
• To improve the stock of plant nutrients in the soil
• To improve the efficiency of plant nutrients
• To improve physical conditions of soils
43. Neem cake & N use efficiency
• Neem cake has good nitrification inhibition
capacity (35% of applied N is lost through
denitrification). When neem cake is mixed with
urea, the rate of inhibition increases with
increasing proportion of neem cake. Neem
cake retains ammonium N for longer period
and higher NH4
+ - N contents are noticed in soil
with neem coated urea application.
44. Neem cake & N use efficiency
(contd.)
• Application of neem cake along with
Sesbania rostrata incorporation resulted
in significant reduction in nitrification
and population of nitrifying bacteria in
soil.
46. ALTERNATE STRATEGIES
• Use Organic manures
• Use soil microbes which can
1.Fix atmospheric nitrogen
2.Solubilize or mobilize “P” and other nutrients
3.Produce growth promoting substances
4.Produce siderophores, antifungal compounds, metabolites
and volatiles
47. ADVANTAGES OF USING BIO-FERTILIZERS
• Can replace 25-30 % of chemical ‘N’ and phosphatic fertilizers
• Bio-fertilizers being cheap provide highly cost effective
supplement of chemical fertilizers
• Increase farm productivity, 15 – 30 %
• Activates soil biologically thereby increasing natural fertility of
soil, which causes sustainable agriculture
• Help in stimulating plant growth in general and roots in particular
as they serve various growth promoting hormones like auxin,
gibberellins etc and vitamins.
48. ADVANTAGES OF USING BIO-FERTILIZERS
• They help in better nutrient uptake and increase tolerance towards
drought and moisture stress.
• Secrete some fungi static and antibiotic like substances, which reduce
the incidence of various soil borne diseases. It has got antagonistic
behaviour against pathogens.
• They help to proliferate and survival of other beneficial microorganisms
in soil.
• Help in decomposing plant residues in soil, thereby improving C/N ratio,
improving soil texture and structure. Also help in increasing water-
holding capacity.
52. Phosphate solubilizing micro-organisms
• Indian soils are very poor in P content.
• Only about 10-15% of the applied P
becomes available to the crop and the
remaining part gets converted into
insoluble/unavailable forms.
• About 130 million tones of low grade P is
deposited (non-available) in our soil, but
plant can not utilize this P directly.
53. Potash mobilizing bacteria (contd.)
• Frateuria aurantia is capable of
mobilizing elementary or fixed K into a
usable form to the plants.
• Increase K availability level to the
magnitude of 5-60 kg/ha.
• Increase banana yield by 20%.
54. Arbuscular mycorrhizal fungi (AMF)
• AMF are obligate symbionts which develop
both intra and extra metrical hyphae that
extends to far areas away from the roots and
increases the absorptive surface area for P and
Zn by mycorrhizal root system.
• Helpful in the biological control of root
pathogens.
• Save P fertilizers by 50%.
55. Enhancing nutrient use efficiency
Method of application
• Soil application: Fertilizers should be
applied in active root zone.
• Foliar application: Fertilizers should
be sprayed on to new flush.