FERTILIZER CALCULATIONS AND PREPARATION OF NPK STOCK SOLUTIONS. Read this detailed explanation of how to calculation fertilizers content, and convert amount of nutrient to amount of fertilizers. All you needed to know in order to feed your plants properly. www.haifa-group.com

1. Fertilizer Calculations and Preparation
of NPK stock solution

2. Calculation fertilizers content
Convert amount of nutrient to amount of fertilizer
 Quantitative
 Proportional
Preparation of NPK mother / stock solution
Fertilizer Stock Solution Calculation
Determine stock solution Injection rate
Contents

3. The content of the fertilizers is declared in by percentages of nutrient
out of total weight.
Polyfeed 17-10-27 contains:
Calculation of fertilizers content
17-10-27
Table marked in red is an excel spreadsheet please, click to active
variable / input in the cells paint in orange, are adjustable
N P2O5 K2O
14 7 21
How much Nitrogen in 1 kg ?
14 / 100 = 0.14 Kg of N

4. 1. Applying: 15 units of N, 7.5 units of P2O5 and 22.5 units of K2O. Units = Kg.
2. Finding the Ratio:
3. Choosing the suitable fertilizer:the desired ratio 2:1:3 exists in 14-7-21
N:P2O5:K2O accordingly.
Calculations nutrient from fertilizers
Table marked in red is an excel spreadsheet please, click to active
variable / input in the cells paint in orange, are adjustable
N P2O5 K2O
Requierd amount kg 15 7.5 22.5
Division by the lowest amount 7.5
The ratio is 2 : 1 : 3

5. 4. How much fertilizer to apply:
We can choose one of the nutrients, usually Nitrogen is used and divide
him by the fertilizer weight concentration.
Calculations nutrient from fertilizers
For applying 12 Kg of N by using Poly feed 14-07-21
Table marked in red is an excel spreadsheet please, click to active
variable / input in the cells paint in orange, are adjustable
N P2O5 K2O
14 7 21
How much Nitrogen in 1 kg ?
14 / 100 = 0.14 Kg of N
Nitrogen requierd quantity kg
12 / 0.14 = 86 Kg of 14 - 07 - 21

6. For applying 11 Kg of P2O5 by using Poly feed 14-07-21
Calculations nutrient from fertilizers
Table marked in red is an excel spreadsheet please, click to active
variable / input in the cells paint in orange, are adjustable
N P2O5 K2O
14 7 21
How much P2O5 in 1 kg ?
7 / 100 = 0.07 Kg of P2O5
P2O5 requierd quantity kg
11 / 0.07 = 157 Kg of 14 - 07 - 21

7. Derived from dry / solid fertilizer kg ha
Rr = recommended nutrient rate (kg ha)
Fw = Weight of fertilizer (kg ha)
Cn = Concentration of nutrient in the fertilizer %
Potassium (K2O) recommended rate 7.5 kg ha
Fertilizer to be used Multi K 46% of K2O
Determining the amount of fertilizer to be applied per unit of land
Fw = Rr X 100
Cn
Table marked in red is an excel spreadsheet please, click to active
variable / input in the cells paint in orange, are adjustable
7.5 * 100
= 16.30 kg/ha
46

8. Derived from dry / solid fertilizer
The recommended rate in ppm (parts per million)
Fw = fertilizer amount gr. / m3
Nc = required nutrient concentration in the water irrigation (ppm)
Cn = concentration of the nutrient in fertilizer (%)
Example:
50 ppm of phosphorus is recommended
Fertilizer in use - Haifa MAP 61% P2O5
Determining the amount of fertilizer per m3 of irrigation water
Fw = Nc X 100
Cn
Table marked in red is an excel spreadsheet please, click to active
variable / input in the cells paint in orange, are adjustable
50 * 100
= 81.97 gr.
61

9. Determining the amount of fertilizer per m3 of irrigation water
Fw = Nc X 100
Cn X D
Derived from liquid fertilizer
The recommended rate in ppm (parts per) million
Fw = fertilizer amount l / m3
Nc = required nutrient concentration in the water irrigation (ppm)
Cn = concentration of the nutrient in fertilizer (%)
D = density kg/m3
Example:
50 ppm of phosphorus is recommended.
Fertilizer in use - Haifa Phosphoric Acid 61% P2O5.
Density 1.68 kg L
50 * 100
61 * 1.68
= 48.79 cc or 0.0487 l
Table marked in red is an excel spreadsheet please, click to active
variable / input in the cells paint in orange, are adjustable

10. Fertigation - Quantitative
Fertilizers
kg/day
Daily nutrients requirement
kg/day
Growth stage
ANMAPMulti KK2OP2O5N
0.751.62.2111Establishment
2.56.531.52Vegetative – flowering
4.22.5104.51.53Flowering – fruit set
7.53.2167.525Fruit development
3.01.66.5312Maturity - Harvest

11. Fertigation - Quantitative
Irrigation duration (hour)
1 2 3
Table marked in red is an excel spreadsheet please, click to active
variable / input in the cells paint in orange, are adjustable
Daily requirement
N P2O5 K2O Multi K MAP AN
Flowering – fruit set 3 1.5 4.5 9.8 2.5 4.2
Field area ha. 1 1 1 1
Irrigation interval days 3 3 3 3
Total fertilizers to be applied kg 29.3 7.4 12.6
Fertilizers
Kg /haKg / ha
Growth stage

12. Fertigation - proportional
Fertilizers
g/m3
Daily nutrients requirement
g/m3
Growth stage
ANMAPMulti KK2OP2O5N
8080110505050Establishment
14510030414060100Vegetative –
appearance 1st cluster
17011539018070120Appearance 1st cluster -
fruit set ( 4th cluster)
18013052024080140Fruit set ( 4th cluster) -
Picking
200160610280100160Picking
17011539018070120Last 6 weeks of picking
(soilless – detached culture)

13. Preparation of NPK mother solution
Recommendation:
100 ppm of N
60 ppm of P205
140 ppm of K20
Fertilizers
g/m3
Daily requirement
g/m3
Growth stage
ANMAPMulti KK2OP2O5N
8080110505050Establishment
14510030414060100Vegetative –
appearance 1st cluster

14. Preparation of NPK mother solution
From desired nutrient at the irrigation water (drip) to the required
concentrated stock solution (opt. I)
The required nutrients concentration in the irrigation water are:
As the given injection rate of the fertilizer pump is 3l / m3
of the irrigation water.
Each liter of the stock solution should contain
N P2O5 K2O
gr. / m3 (ppm)
100 60 140
N P2O5 K2O
gr. / L
33.3 20 46.6

15. Preparation of NPK mother solution
We start calculation with the required quantity of potassium derived from
Potassium Nitrate (13 -00-46).
Since we need 46.6 grs of K2O in each liter of the stock solution.
We have to dissolve 46.6*100/46 = 101.3 grs of Potassium Nitrate (13 -00-46)
in each liter.
101.3 grs of Potassium Nitrate (00 -00-46) also supply 13.1 grs of nitrate
nitrogen (NO3
-) = 13*101.4/100

16. Preparation of NPK mother solution
Secondly we take care of the required phosphorus quantity gr. / L
We now calculate the required quantity of phosphorus derived from Mono
Ammonium Phosphate (12 -61-00).
since we need 20 grs of P2O5 in each liter of the stock solution.
we have to dissolve 20*100/61 = 32.7 grs of Mono Ammonium Phosphate in
each liter.
32.7 grs of Mono Ammonium Phosphate also supply 3.9 grs of ammonium
nitrogen (NH4
+) = 12*32.7/100
N P2O5 K2O
gr. / L
33.3 20 46.6

17. Preparation of NPK mother solution
At last we have to take care of the required nitrogen quantity gr. / L
We now calculate the required quantity of nitrogen derived from Ammonium
Nitrate (34 -00-00).
we need 33.3 grs of N in each liter of the stock solution but we have to
deduct 17 grs obtained already from.
Potassium Nitrate & Mono Ammonium Phosphate thus, the remaining
required quantity is only 16.3 grs
we have to dissolve then 16.3*100/34 = 47.9 grs of Ammonium Nitrate.
N P2O5 K2O
gr. / L
33.3 20 46.6

18. Preparation of NPK mother solution
What is the amount of fertilizer to be added in a 100 liter tank?
As known that the injection rate (dilution relation) is 3 liters/m3 of irrigation
water.
Calculation is as the following:
101.4*100/1000 = 10.14 kilos of Potassium Nitrate
32.7*100/1000 = 3.27 kilos of Mono Ammonium Phosphate
47.9*100/1000 = 4.794 liters Ammonium Nitrate

19. Preparation of NPK mother solution
Summary: preparation of 100L of stock solution NPK:
Fill up 70 L of water in the tank,
Add 3.27 kilos of Mono Ammonium Phosphate
Add 10.14 kg of Potassium Nitrate KNO3
Add 4.79 kg of Ammonium Nitrate
Complete with water to 100 L

20. Preparation of Stock Solution
From desired nutrient at the irrigation water to the required concentrated
stock solution (opt. I)
1. Required nutrients concentration in the irrigation water.
Stock solution injection rate - 3 L / m3
2. Each liter of the stock solution should contain
N P2O5 K2O
gr. / m3 (ppm)
100 60 140
N P2O5 K2O
gr. / L
33.3 20 46.6

21. Preparation of Stock Solution
3. Choosing the WSF fertilizers to be used
K2O
Multi–K
13-00-46
N
Ammonium nitrate
34-00-00
P2O5
Haifa MAP
12-61-00

22. Preparation of Stock Solution
4. Calculating the required fertilizers quantity to be dissolved in the stock solution tank.
N P2O5 K2O
gr. / l
33 20 47
20/0.61 60/0.46
Derived from Multi-K 13 32.8 101
Derived from MAP 4 = 32.8 gr./l MAP = 130 gr./l Multi-K
Balance N gr./l 16
9/0.34
48
= 27 gr.l Amm. nitrate
Stock solution tank l. 100
Dissolved Fertilizers 100*27/1000 100*32.8/1000 100*130/1000
quantity kg 4.76 3.28 10.1
N P2O5 K2O
gr. / l
Table marked in red is an excel spreadsheet please, click to active
variable / input in the cells paint in orange, are adjustable

23. Preparation of Stock Solution
4. Calculating the required fertilizers quantity to be dissolved in the stock solution tank.
N P2O5 K2O
gr. / l
33 20 47
20 47
0.61 0.46
= =
Derived from Multi-K 13 33 101
Derived from MAP 4 gr./l MAP gr./l Multi-K
Balance N gr./l 16
16
0.34
=
48
gr.l Amm. nitrate
Stock solution tank l. 100
100 * 48 100 * 33 100 * 101
1000
=
10.1
Dissolved Fertilizers
quantity (kg)
1000
=
3.3
1000
4.8
=
Table marked in red is an excel spreadsheet please, click to active
variable / input in the cells paint in orange, are adjustable

24. Preparation of Stock Solution
Fertilizer quantity to be dissolved in 1000 L stock solution tank.
Each liter of the stock solution contains gr.
N P2O5 K2O
33.3 20 46.6
Multi-K 101.4 g/ l x 1000 = 101.4 kg / m3
MAP 32.8 g/ l x 1000 = 32.8 kg / m3
AN 48 g/ l x 1000 = 48 kg / m3
1000 liters

25. Preparation of Stock Solution
From desired nutrient at the irrigation water to the required concentrated stock
solution (opt. II)
N P2O5 K2O
Required nutrients conc. in the irrig. water (gr. / m3 - ppm) 100 60 140
Fertilizers in use (gr. / m3 - ppm)
N, K20 - derived from Multi-K 40 304
N, P2O5 - derived from MAP 12 98
Balance of N 49
N, derived from Amm. Nitrate 143
Fertilizers in the irrigation water (gr. / m3 - ppm)
Multi-K 304
MAP 98
Amm. nitrate 143
N form
Table marked in red is an excel spreadsheet please, click to active
variable / input in the cells paint in orange, are adjustable

26. Preparation of Stock Solution
Kindly feed the calculated fertilizers quantity from previous slide
Fertilizers in the irrigation water (gr. / m3 - ppm)
Multi-K 304
MAP 98
Amm. nitrate 143
Stock solution tank l. 100
Dissolving rate % 18
Total dissolved qua. Kg 18
Dissolved fertilizers in the stock solution tank (kg)
Multi-K 10.0
MAP 3.2
Amm. nitrate 4.7
N P2O5 K2O
Nutrients conc. in the stock solution gr. / l 33.0 19.8 46.2
Required nutrients conc. in the irrig. water (gr. / m3 - ppm) 100 60 140
Pump injection rate l. per each m
3
of irrigation water 3.03
Table marked in red is an excel spreadsheet please, click to active
variable / input in the cells paint in orange, are adjustable

27. Preparation of Stock Solution
N P2O5 K2O
Required nutrients conc. in the irrig. water (gr. / m3 - ppm) 100 60 140
Fertilizers in use (gr. / m3 - ppm)
N, K20 - derived from Multi-K 40 304
N, P2O5 - derived from MAP 12 98
Balance of N 49
N, derived from Amm. Nitrate 143
Fertilizers in the irrigation water (gr. / m3 - ppm)
Multi-K 304
MAP 98
Amm. nitrate 143
N form
NH4 % 36
NO3 % 64
Stock solution tank l. 100
Dissolving rate % 18
Total dissolved qua. Kg 18
Dissolved fertilizers in the
stock solution tank kg
Multi-K 10.0
MAP 3.2
Amm. nitrate 4.7
Nutrients level in the stock solution N P2O5 K2O
gr. l 33.0 19.8 46.2
Required nutrients level 100 60 140
at the irrigation water (ppm)
Required pump injection rate (l)
per each m3 of irrigation water
3.03
Table marked in red is an excel spreadsheet please, click to active
variable / input in the cells paint in orange, are adjustable

28. Preparation of Stock Solution - Two tanks
From desired nutrient at the irrigation water to the required concentrated stock solution
Table marked in red is an excel spreadsheet please, click to active
variable / input in the cells paint in orange, are adjustable
N P2O5 K2O CaO MgO
Required nutrients conc. in the irrig. water (gr. / m3 - ppm) 120 60 160 90 40
Fertilizers in use (gr. / m3 - ppm)
N, K20 - derived from Multi-K 45 348
N, P2O5 - derived from MAP 12 98
N, CaO derived fro Haifa Cal 53 340
MgO derived from MGS 250
Balance of N 10
N, derived from Amm. Nitrate 30
Fertilizers in the irrigation water (gr. / m3 - ppm)
Multi-K 348
MAP 98
Amm. nitrate 30
N, CaO derived fro Haifa Cal 340
MgO derived from MGS 250
N form
NH4 % 14
NO3 % 86

29. Preparation of Stock Solution - Two tanks
Kindly feed the calculated fertilizers quantity from previous slide
Table marked in red is an excel spreadsheet please, click to active
variable / input in the cells paint in orange, are adjustable
Fertilizers in the irrigation water (gr. / m3 - ppm)
Multi-K 348
MAP 98
Amm. nitrate 30
N, CaO derived fro Haifa Cal 340
MgO derived from MGS 250
Stock solution tank l. 100 100
Dissolving rate % 20 60
Total dissolved qua. Kg 20 30
Dissolved fertilizers in the
stock solution tank (kg)
Multi-K 7.3 Multi-K 7.3
MAP 4.1 Haifa Cal 17.7
Amm. nitrate 1.3
MGS 9.0
Nutrients level in the stock solution N P2O5 K2O N CaO MgO
gr. l 18.8 25.2 67.1 11.3 19.0 14.5
Required nutrients level 67 60 160 53 90 40
at the irrigation water (ppm)
Required pump injection rate (l)
per each m3 of irrigation water
2.38 4.74
TANK I ITANK I

30. Preparation of Stock Solution - Two tanks
Table marked in red is an excel spreadsheet please, click to active
variable / input in the cells paint in orange, are adjustable
N P2O5 K2O CaO MgO
120 60 160 90 40
Fertilizers in use (gr. / m3 - ppm)
N, K20 - derived from Multi-K 45 348
N, P2O5 - derived from MAP 12 98
N, CaO derived fro Haifa Cal 53 340
MgO derived from MGS 250
Balance of N 10
N, derived from Amm. Nitrate 30
Fertilizers in the irrigation water (gr. / m3 - ppm)
Multi-K 348
MAP 98
Amm. nitrate 30
N, CaO derived fro Haifa Cal 340
MgO derived from MGS 250
N form
NH4 % 14
NO3 % 86
Stock solution tank l. 100 100
Dissolving rate % 20 60
Total dissolved qua. Kg 20 30
Dissolved fertilizers in the
stock solution tank (kg)
Multi-K 7.3 Multi-K 7.3
MAP 4.1 Haifa Cal 17.7
Amm. nitrate 1.3
MGS 9.0
Nutrients level in the stock solution N P2O5 K2O N CaO MgO
gr. l 18.8 25.2 67.1 11.3 19.0 14.5
Required nutrients level 67 60 160 53 90 40
at the irrigation water (ppm)
Required pump injection rate (l)
per each m3 of irrigation water
2.38 4.74
Required nutrients conc. in the irrig. water (gr. / m3 - ppm)
TANK I TANK I I

31. Preparation of Stock Solution
From concentrated stock solution to dilute fertilizer solution (irrigation water)
1. Desired nutrients concentration in the irrigation water.
2. Injector ratio = 1:333; dilution factor = 333
determines the concentration of the stock solution.
injection rate – 3l / m3
Nc- desired concentration in parts per million (ppm) = 140
Ir - injector ratio 1: 333; dilution factor = 333
Cn - fertilizer analysis = 13-00-46 (46% K2O)
C - conversion constant to be used to make 1 liter of concentrated stock solution (gr) = 10
N P2O5 K2O
gr. / m3 (ppm)
100 60 140
Nc X Ir
Cn X C
= Fertilizer (gr.) / 1 I stock solution

32. Preparation of Stock Solution
3. WSF fertilizers to be used
4. Calculating the required fertilizers quantity to be dissolved in the
stock solution tank.
Multi–K
13-00-46
Ammonium nitrate
34-00-00
Haifa MAP
12-61-00
100 * 333 60 * 333 140 * 333
34 * 10 61 * 10 46 * 10
gr./ l Amm. nitrate
N, derived from Multi-K 13
N, derived from MAP 4
Total N gr./l (ppm) 17
17.1
0.34
Balance N - Amm. nitrate gr./l 48
Stock solution tank l. 100
Dissolved Fertilizers 10.1
quantity (kg) 3.3
4.8
Multi-K
MAP
Amm. Nitrate
= 97.9
= 50.3
= 101.3
gr./l Multi-K
= 32.8
gr./l MAP
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33. Fertilizer Requirements for use in Nutrigation
High nutrient content in solution
Total solubility under field conditions
Rapid dilution in irrigation wate
Grade fine,
Does not clog emitters
Low insoluble materials
Minimum conditional agents conten
Compatible with other fertilizers
Compatible with irrigation water
It does not cause sharp pH variations in irrigation water
Low corrosivity

34. Fertilizer properties
to be considered when preparing stock solution
Solubility - fully soluble
Purity - free of detrimental elements, chloride Cl-
Dissolution time
Concentration of the solution
Compatibility
pH tendency
EC contribution - salt index

35. Calculations fertilizers transformations
In most of the world fertilizers are related by units: N as elemental, P
as P2O5 and K as K2O.
ToFromToFrom
18NH4
+14N-NH423N-NH430NH4
+
274NO3
-62N-NO30N-NO3NO3
-
0P2O5P39P90P2O5
0PO4
-P29P90PO4
-
0K2OK0KK2O
0CaCO3Ca0CaCaCO3
0CaOCa0CaCaO
0MgCO3Mg0MgMgCO3
0MqOMg0MgMqO

36. Calculations fertilizers transformations
Meq/l - ppm conversion table
To ppmFrom Meg/I
0N0N-NO3
- or NH4
+
31PH2 PO4
-
0K+90K+
0Ca2+90Ca2+
0Mg2+Mg2+
0SO4
2-SO4
2-
0Na+Na+
0CI-CI-
To Meq/IFrom ppm
0N0N-NO3
- or NH4
+
0PH2 PO4
-
0K+90K+
10Ca2+90Ca2+
9.996Mg2+Mg2+
0SO4
2-SO4
2-
0Na+Na+
0CI-CI-

37. Dry WSF fertilizers (chloride free) and their respective solubilities at 3 tem. levels
F e r t i l i z e r s N P P2O5 K K2O +
SOLUBILITY
g / L Water
10º C 20º C 30º C
Urea 46 0 0 0 0 450 510 570
Ammonium Nitrate 33.5 0 0 0 0 610 660 710
Ammonium Sulphate 20 0 0 0 0 24 S 420 430 440
Multi Cal Calcium Nitrate 15.5 0 0 0 0 26.5 CaO 950 1,200 1,500
MAP Mono Ammonium Phosphate 12 26.6 61 0 295 374 464
0 22.6 52 28 34 183 226 280MKP Mono Potassium Phosphate
Multi-K –Potassium Nitrate 13 0 0 38 44 219 330 480
Magnisal 11-0-0+ 16 Mg O 11 0 0 0 0 16 MgO 210 320 450
Magnesium Sulphate 15.5 0 0 0 0 26.5 CaO 950 1,200 1,500
Potassium Sulphate 0 0 0 41.5 52 18 S 80 100 110

38. How to calculate a Cl free blend (based on Urea)
The following example is a 4 steps for blend 20 N - 20 P205- 20 K20 with
basic fertilizers:
Multi-K 13-0-46
MAP 12-61-0
Urea 46-0-0
1. Mutiply the desired level of potassium (K2O) by 2.174 (100:46):
20 x 2.174 = 43.48 43.48% Multi-K
2. Multiply the desired level of Phosphate (P2O5) by 1.639 (100:61):
20 x 1.639 = 32.78 32.78 % MAP
20 – 8.7 P – 16.6 K
20 x 0.43 = 8.7 P
20 x 0.83 = 16.6 K

39. How to calculate a Cl free blend (based on Urea)
3. Calculate Nitrogen suplied by Multi-K and MAP
43.48 x 13% = 5.65 % N suplied by Multi-K
32.78 x 12 % = 3.93 % N suplied by MAP
5.65 + 3.93 = 9.58 %
4. Calculate Multi-K and MAP rate in the blend
100 – (43.48 + 32.78) = 23.74 % UREA}
23.74 x 46% = 10.92 + (5.65+3.93) = 20.5 N
300 Gr 20-20-20 per 1Lit of water = 6%-6%-6%(W/V) = 60-60-60 Content Gr/Lit ( N-P205-K20)
300 Gr 20-8.7-16.6 per 1 Lit of water = 6%-2.61%-4.98% (W/V) = 60-26.1-49.8 Gr/Lit (N-P-K)

40. Analysis of stock solution
Analysis of stock solution by dissolving 300 g dry soluble fertilizer and filling water to
1 Liter and the plant nutrinet content.
Ratio
Dry Soluble Mixed Fertilizer Fertilizer solution Content in the solution
W/W % W/V % g/L
N- P2O5 - K2O
1:1:1
20-20-20 6-6-6 60:60:60
18-18-18 5.4-5.4-5.4 54:54:54
2:1:3 20-9-28 6-2.7-8.4 60:27:84
2:1:2 23-11-22 6.9-3.3-6.8 69:33:66
1:2:1 16-32-16 4.8-9.6-4.8 48:96:48
1:1:2 15-15-30 4.5-4.5-9 45:45.90
2:1:1 28-14-14 8.4-4.2-4.2 84:42:42
3:1:3 24-8-24 7.2-2.4-7.2 72:24:72
2:1:3 17-10-27 5.1-3-8.1 51:30:81
1.5:1:3.5 14-10-35 4.2-3-10.5 42:30.105
1.3:1:3.3 14:11:34 4.2-3.3-10.2 42:33:102
2:1:4 16-8-32 4.8-2.4-9.6 48:24:96
1:0:3 13-0-46 3.9-0-13.8 39:0:138
300 Gr 17 -10-27 per 1Lit of water = 5.1%-3%-8.1%(W/V) = 51-30-81 Content Gr/Lit ( N-P205-K20)

41. Thank You
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