1. Fertilizer Materials and Calculation
Nutrient Management
Fertilizer Materials and Calculation
Part 1: Understanding the PalayCheck System

2. FERTILIZER TERMINOLOGIES
Fertilizer – any substance which is added to the soil or applied to the plant to supply the elements essential for plant nutrition
Fertilizer grade – the guaranteed percentage of total nitrogen (N), available phosphorus (P2O5), and water soluble potassium (K2O), in that order, in a fertilizer material
0% K2O
16% N
20% P2O5

3. FERTILIZER TERMINOLOGIES
Total plant food – the total percentage of nutrients (usually of N,P,K and S) in a fertilizer material
= 46% total plant food
= 54% total plant food
Carrier – a material that is necessary to hold the fertilizer element in a form suitable for use
100% – 46% total plant food = 54% carrier

4. FERTILIZER TERMINOLOGIES
Filler – a material used to provide the fertilizer with the desired amount of nutrient per unit of weight, to make application easier, or to reduce the absorption of water from the air
Fertilizer recommendation – the amount (kg) of N,P2O5, and K2O recommended per hectare
= 90 kg N, 30 kg P2O5, and 60 kg K2O per hectare application

5. Classification of Fertilizer Materials
According to form
Natural organic
Chemical or inorganic
Natural chemical
Synthetic chemical
According to fertilizer elements present
Single
Incomplete
Complete
Mixed

6. According to form
1. Natural organic – any fertilizer of plant and/or animal origin that has undergone decomposition.
Examples: Commercial organic fertilizer (OF), compost, chicken manure
Commercial OF may either be pure organic or fortified organic:
Organic Matter (%)
C:N Ratio
Moisture Content (%)
N+P2O5+K2O (%)
Pure Organic
≥ 20
12:1
≤ 35
≤ 7
Fortified Organic
> 7

7. According to form
2. Chemical or inorganic – any fertilizer material which is natural or synthetic product of chemical reaction of certain raw materials.
Natural chemical – rock phosphate, Chilean nitrate of soda, most potassium materials
Synthetic chemical – ammonium sulfate, ordinary superphosphate, ammonium phosphate, complete fertilizer; Urea is synthetic but in organic form.

8. According to number of fertilizer elements present
Single fertilizers – contain only one of the 3 major fertilizer elements (N,P, and K) Examples: Urea, Ammonium sulfate, ordinary superphosphate, muriate of potash, sulfate of potash
Incomplete fertilizers – contain 2 of the 3 major fertilizer elements Examples: ammonium phosphate, , potassium nitrate, potassium phosphate, urea superphosphate ( )

9. According to number of fertilizer elements present
Complete fertilizers – contain all the 3 major fertilizer elements Examples: ; ; ;
Mixed fertilizers – contain 2 or more of the major fertilizer elements that are supplied by 2 or more fertilizer materials Examples: ammonium phosphate + muriate of potash; urea superphosphate ( )

10. Why study fertilizer grades
and fertilizer computation?
Consider this:
If Shane needs a teaspoon of sugar to sweeten her juice but there is no sugar available, can she use honey instead?
If Aling Mena does not have enough soy sauce for the adobe she’s cooking, can she add salt? How much?
If Mang Ado needs to apply fertilizer at a recommended rate of but no complete fertilizer is available, what other fertilizers and how much of it should he use to meet the recommendation?

11. Common fertilizer grades in the market
50 kg
Complete fertilizer
50 kg sack:
14% nitrogen
14% phosphorus
14% potassium
7 kg nitrogen
7 kg phosphorus
7 kg potassium
FERTILIZER
50 kg
Ammonium phosphate
50 kg sack:
16% nitrogen
20% phosphorus
0% potassium
8kg nitrogen
10kg phosphorus
0kg potassium

12. Other common fertilizers: Ammonium sulfate (21-0-0) Solophos (0-18-0)
50 kg
46-0-0
Urea
50 kg sack:
46% nitrogen
0% phosphorus
0% potassium
23 kg nitrogen
0 kg phosphorus
0 kg potassium
Other common fertilizers:
Ammonium sulfate (21-0-0)
Solophos (0-18-0)
Muriate of potash (0-0-60)
Urea superphosphate ( )
46% x 50 kg
100

13. Fertilizer Calculation
If Mang Ado needs to apply fertilizer at a recommended rate of but no complete fertilizer is available, what other fertilizers and how much of it should he use to meet the recommendation?
Amount of Fertilizer Material (kg)
Recommended Rate (kg nutrient/ha) x Area (ha) =
Percent Nutrient in Fertilizer Material

14. 2 1 3 Use a combination of 3 single fertilizers 46-0-0 0-0-60 21-0-0
0-0-60 2 1
21-0-0
0-0-60
0-18-0
Use a combination of incomplete and single fertilizer materials
0-0-60 3
46-0-0
Use a combination of complete and single fertilizer materials
OPTIONS

15. Option 1. To calculate the amount of fertilizer materials for 1 ha at the recommended rate of using a combination of single fertilizers:
(ammonium sulfate)
(ordinary superphosphate)
(muriate of potash or potassium chloride)

16. Amount of (kg)
90 kg N/ha x 1 ha 0.21 =
428.6
Amount of (kg)
30 kg P2O5/ha x 1 ha
0.18 =
166.7
Amount of (kg)
60 kg K2O/ha x 1 ha
0.60 =
100.0
Therefore, Mang Ado must apply kg , kg , and kg to satisfy the recommended rate of

17. Option 2. To calculate the amount of fertilizer materials for 1 ha at the recommended rate of using a combination of incomplete and single fertilizers:
(ammonium phosphate
(urea)
(muriate of potash)

18. 90 kg N – kg N from 150 kg 16-20-0/ha x 1 ha
Amount of (kg)
30 kg P2O5/ha x 1 ha
0.20 =
150.0
Amount of (kg)
90 kg N – kg N from 150 kg /ha x 1 ha
0.46 =
90 – (150 x 0.16)
90 – 24 66 =
Amount of (kg)
60 kg K2O/ha x 1 ha
0.60 =
100.0
Therefore, he must apply kg , kg , and kg to satisfy the recommended rate of

19. Option 3. To calculate the amount of fertilizer materials for 1 ha at the recommended rate of using a combination of complete and single fertilizers:
(complete)
(urea)
(muriate of potash)

20. 90 kg N – kg N from 214.3 kg 14-14-14/ha x 1 ha 0.46 =
Amount of (kg)
30 kg P2O5/ha x 1 ha
0.14 =
214.3
Amount of (kg)
90 kg N – kg N from kg /ha x 1 ha
0.46 =
90 – (214.3 x 0.14)
90 – 30 60
130.4
Amount of (kg)
60 kg K2O – kg K2O from kg /ha x 1 ha
0.60 =
60 – (214.3 x 0.14)
60 – 30 30
50.0
Therefore, he must apply kg , kg , and 50.0 kg to satisfy the recommended rate of

21. Determine the least expensive fertilizer combination that can satisfy the recommended rate ( ).

22. 0-0-60
Cost of option 1. combination of single fertilizers:
0-18-0
21-0-0
21-0-0
428.6 kg
50 kg/bag =
P 4,714.60
x P 550/bag
0-18-0
166.7 kg
50 kg/bag =
P 1,833.70
x P 550/bag
0-0-60
100.0 kg
50 kg/bag =
P 1,650.00
x P 825/bag
TOTAL COST = P 8,198.30

23. Cost of option 2. combination of incomplete and single fertilizers:
46-0-0
Cost of option 2. combination of incomplete and single fertilizers:
0-0-60
150.0 kg
50 kg/bag =
P 2,460.00
x P 820/bag
46-0-0
143.5 kg
50 kg/bag =
P 2,554.30
x P 890/bag
0-0-60
100.0 kg
50 kg/bag =
P 1,650.00
x P 825/bag
TOTAL COST = P 6,664.30

24. Cost of option 3. combination of complete and single fertilizers:
0-0-60
Cost of option 3. combination of complete and single fertilizers:
46-0-0
214.3 kg
50 kg/bag =
P 3,471.66
x P 810/bag
46-0-0
130.4 kg
50 kg/bag =
P 2,321.12
x P 890/bag
0-0-60
50.0 kg
50 kg/bag = P
x P 825/bag
TOTAL COST = P 6,617.78

25. Use a combination of 3 single fertilizers
46-0-0
0-0-60
21-0-0
0-0-60
0-18-0
Use a combination of incomplete and single fertilizer materials
0-0-60
46-0-0
Use a combination of complete and single fertilizer materials

26. CREDITS Ms. Ev Parac Note: Instructional presentation designer:
Adapted from powerpoint presentations developed by: Mr. Salvador Yabes
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Produced in 2011.
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