B Y:D A O - AY E N , C Y R U S

F E L I X , J A C K Y J O H NJ I M E N E Z , J A M E S

Fertilizer Computations

Fertilizer Materials and Calculation

Nutrient Management

Part 1: Understanding the PalayCheck System

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

FERTILIZER TERMINOLOGIES

16% N20% P2O5

0% K2O16-20-

0

Total plant food – the total percentage of nutrients (usually of N,P,K and S) in a fertilizer material

17-0-17-12 = 46% total plant food14-14-14-12 = 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

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+30+60 = 90 kg N, 30 kg P2O5, and 60 kg K2O per hectare application

FERTILIZER TERMINOLOGIES

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

1. Natural organic – any fertilizer of plant and/or animal origin that has undergone decomposition.

Examples: Commercial organic fertilizer (OF), compost, chicken manure

Organic Matter (%) C:N Ratio

Moisture Content (%)

N+P2O5+K2O (%)

Pure Organic ≥ 20 12:1 ≤ 35 ≤ 7

Fortified Organic ≥ 20 12:1 ≤ 35 > 7

According to form

Commercial OF may either be pure organic or fortified organic:

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.

According to form

1. 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

2. Incomplete fertilizers – contain 2 of the 3 major fertilizer elements

Examples: ammonium phosphate, 17-0-17, potassium nitrate, potassium phosphate, urea superphosphate (20-10-0)

According to number of fertilizer elements present

3. Complete fertilizers – contain all the 3 major fertilizer elements

Examples: 14-14-14; 17-7-17; 10-15-15; 12-12-12

4. 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 (20-10-0)

According to number of fertilizer elements present

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 90+30+60 but no complete fertilizer is available, what other fertilizers and how much of it should he use to meet the recommendation?

FERTILIZER

50 kg

14-14-14

Complete fertilizer

14% nitrogen14% phosphorus14% potassium

50 kg sack:

7 kg nitrogen7 kg phosphorus7 kg potassium

Common fertilizer grades in the market

FERTILIZER

50 kg

16-20-0

Ammonium phosphate

16% nitrogen20% phosphorus0% potassium

50 kg sack:

8kg nitrogen10kg phosphorus0kg potassium

FERTILIZER

50 kg

46-0-0

Urea

46% nitrogen0% phosphorus0% potassium

50 kg sack:

23 kg nitrogen0 kg phosphorus0 kg potassium

Other common fertilizers: Ammonium sulfate (21-0-0)Solophos (0-18-0)Muriate of potash (0-0-60)Urea superphosphate (21-10-0)

46% x 50 kg

100

Fertilizer Calculation

Amount of Fertilizer Material (kg)

Recommended Rate (kg nutrient/ha) x Area (ha)=

Percent Nutrient in Fertilizer Material

If Mang Ado needs to apply fertilizer at a recommended rate of 90+30+60 but no complete fertilizer is available, what other fertilizers and how much of it should he use to meet the recommendation?

21-0-00-18-0

0-0-6016-20-0

Use a combination of incomplete and single fertilizer materials

0-0-60

46-0-0

Use a combination of 3 single fertilizers

0-0-60

46-0-0

14-14-14

Use a combination of complete and single fertilizer materials

1 2

3

OPTIONS

Option 1. To calculate the amount of fertilizer materials for 1 ha at the recommended rate of 90 + 30 + 60 using a combination of single fertilizers:

• 21-0-0 (ammonium sulfate)• 0-18-0 (ordinary superphosphate)• 0-0-60 (muriate of potash or potassium chloride)

Therefore, Mang Ado must apply 428.6 kg 21-0-0, 166.7 kg 0-18-0, and 100.0 kg 0-0-60 to satisfy the recommended rate of 90 + 30 + 60.

Amount of 21-0-0 (kg)

90 kg N/ha x 1 ha0.21

= = 428.6

Amount of 0-18-0 (kg)

30 kg P2O5/ha x 1 ha

0.18

= = 166.7

Amount of 0-0-60 (kg)

60 kg K2O/ha x 1 ha

0.60

= = 100.0

16-20-0 (ammonium phosphate 46-0-0 (urea) 0-0-60 (muriate of potash)

Option 2. To calculate the amount of fertilizer materials for 1 ha at the recommended rate of 90 + 30 + 60 using a combination of incomplete and single fertilizers:

Amount of 16-20-0 (kg) 30 kg P2O5/ha x 1 ha

0.20= = 150.0

Amount of 46-0-0 (kg) 90 kg N – kg N from 150 kg 16-20-0/ha x 1 ha0.46=

90 – (150 x 0.16)0.46

= 90 – 240.46

= 660.46

=

= 143.5

Amount of 0-0-60 (kg) 60 kg K2O/ha x 1 ha0.60

= = 100.0

Therefore, he must apply 150.0 kg 16-20-0, 143.5 kg 46-0-0, and 100.0 kg 0-0-60 to satisfy the recommended rate of 90 + 30 + 60

14-14-14 (complete) 46-0-0 (urea) 0-0-60 (muriate of potash)

Option 3. To calculate the amount of fertilizer materials for 1 ha at the recommended rate of 90 + 30 + 60 using a combination of complete and single fertilizers:

Amount of 14-14-14 (kg) 30 kg P2O5/ha x 1 ha0.14

= = 214.3

Therefore, he must apply 214.3 kg 14-14-14, 130.4 kg 46-0-0, and 50.0 kg 0-0-60 to satisfy the recommended rate of 90 + 30 + 60

Amount of 46-0-0 (kg) 90 kg N – kg N from 214.3 kg 14-14-14/ha x 1 ha0.46

=

90 – (214.3 x 0.14)0.46

= 90 – 300.46

= 600.46

= 130.4=

Amount of 0-0-60 (kg) 60 kg K2O – kg K2O from 214.3 kg 14-14-14/ha x 1 ha0.60

=

60 – (214.3 x 0.14)0.60= 60 – 30

0.60= 300.60= 50.0=

Determine the least expensive fertilizer combination that can satisfy the recommended rate (90 + 30 + 60).

21-0-0428.6 kg50 kg/bag= = P

4,714.60x P 550/bag

0-18-0166.7 kg50 kg/bag= = P

1,833.70x P 550/bag

0-0-60100.0 kg50 kg/bag= = P

1,650.00x P 825/bag

TOTAL COST = P 8,198.30

Cost of option 1. combination of single fertilizers:

21-0-0 0-18-0

0-0-60

16-20-0150.0 kg50 kg/bag= = P 2,460.00x P 820/bag

46-0-0143.5 kg50 kg/bag= = P 2,554.30x P 890/bag

0-0-60100.0 kg50 kg/bag= = P 1,650.00x P 825/bag

TOTAL COST = P 6,664.30

Cost of option 2. combination of incomplete and single fertilizers:

16-20-0

0-0-60

46-0-0

14-14-14214.3 kg50 kg/bag= = P 3,471.66x P 810/bag

46-0-0130.4 kg50 kg/bag= = P 2,321.12x P 890/bag

0-0-6050.0 kg

50 kg/bag= = P 825.00x P 825/bag

TOTAL COST = P 6,617.78

Cost of option 3. combination of complete and single fertilizers:

0-0-60

46-0-0

14-14-14

21-0-00-18-0

0-0-6016-20-0

Use a combination of incomplete and single fertilizer materials

0-0-60

46-0-0

Use a combination of 3 single fertilizers

0-0-60

46-0-0

14-14-14

Use a combination of complete and single fertilizer materials

THANK YOU VERY MUCH!!!