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Labeling of fertilizer

February 15, 2024

"NPK" redirects here. For other uses, see NPK (disambiguation).

Many countries have standardized the labeling of fertilizers to indicate their contents of major nutrients.[1][2] The most common labeling convention, the NPK or N-P-K label, shows the amounts of the chemical elements nitrogen, phosphorus, and potassium.

Common labeling conventions edit

The NPK analysis label edit

Fertilizers are usually labeled with three numbers, as in 18-20-10, indicating the relative content of the primary macronutrients nitrogen (N), phosphorus (P), and potassium (K), respectively.

More precisely, the first number ("N value") is the percentage of elemental nitrogen by weight in the fertilizer; that is, the mass fraction of nitrogen times 100. The second number ("P value") is the percentage by weight of phosphorus pentoxide P
2O
5. The third number ("K value") is the equivalent content of potassium oxide K
2O.[3]

For example, a 15-13-20 fertilizer would contain 15% by weight of nitrogen, 13% by weight of P
2O
5, 20% by weight of K
2O, and 52% of some inert ingredient.

Other labeling conventions edit

In the U.K., fertilizer labeling regulations allow for reporting the elemental mass fractions of phosphorus and potassium. The regulations stipulate that this should be done in parentheses after the standard N-P-K values, as in "15-30-15 (15-13-13)".[4]

In Australia, macronutrient fertilizers are labeled with an "N-P-K-S" system, which uses elemental mass fractions rather than the standard N-P-K values and includes the amount of sulfur (S) contained in the fertilizer. [5]

Fertilizers with additional macronutrients (S, Ca, Mg) may add more numbers to the N-P-K ratio to indicate the amount. The additional numbers are similarly reported in the oxide mass fraction form. For example, a Polish fertilizer labeled "NPK (Ca,S) 4-12-12 (14-29)" has an equivalent of 14% soluble calcium oxide and 29% total sulfur trioxide.[6]

Converting nutrient analysis to composition edit

The values in an NPK fertilizer label are related to the concentrations (by weight) of phosphorus and potassium elements as follows:

  • P
    2    O
    5     consists of 56.4% elemental oxygen and 43.6% elemental phosphorus by weight. Therefore, the elemental phosphorus percentage of a fertilizer is 0.436 times its P value.
  • K
    2    O     consists of 17% oxygen and 83% elemental potassium by weight. Therefore, the elemental potassium percentage is 0.83 times the K value.

The N value in NPK labels represents actual percentage of nitrogen element by weight, so it does not need to be converted.

So, for example, an 18−51−20 fertilizer contains by weight

  • 18% elemental nitrogen,
  • 0.436 × 51 = 22% elemental phosphorus, and
  • 0.83 × 20 = 17% elemental potassium.

As another example, the fertilizer sylvite is a naturally occurring mineral consisting mostly of potassium chloride, KCl. Pure potassium chloride contains one potassium atom (whose atomic mass is 39.09 g/mol) for every chlorine atom (whose atomic mass is 35.45 g/mol). Therefore, pure KCl is 39.09/(39.09 + 35.45) = 52% potassium and 48% chlorine by weight. Its K value is therefore 52/0.83 = 63; that is, a fertilizer that gets all its potassium from K
2O and has the same potassium contents as pure KCl would have to be 63% K
2O. Pure KCl fertilizer would thus be labeled 0-0-63. Since sylvite contains other compounds that contribute no N, P, or K, it is usually labeled 0-0-60.

NPK values for commercial fertilizers edit

NPK values for various synthetic fertilizers[7] edit

NPK values for mined fertilizer minerals edit

NPK values for biosolids fertilizers and others edit

See also edit

References edit

  1. ^ Chambers, Albert; Sally Rutherford (27 November 2007). "Voluntary Standards for the Fertilizer and Supplements Industry". Retrieved 3 February 2010.
  2. ^ "Draft Code of Practice for Fertilier Description and Labeling". Fertilizer Industry Federation Association (FIFA). 15 September 2008. Retrieved 3 February 2010.
  3. ^ nutrient_analysiswww.flairform.com 22 October 2014 28 October 2014 at the Wayback Machine
  4. ^ UK Fertilizers Regulations 1990, Schedule 2 Part 1, Para. 7.
  5. ^ (PDF). Australian Government Department of Agriculture, Fisheries and Forestry. Archived from the original (PDF) on 28 February 2015. Retrieved 27 October 2014.
  6. ^ "NPK (Ca,S) 4-12-12 (14-29) Lubofoska". skladrolny.pl. Retrieved 15 December 2022. Lubofoska is a fertilizer applied before sowing...
  7. ^ NPK (Fertilizer) chemicalland21.com accessed 15 December 2022
  8. ^ a b c d J. B. Sartain, University of Florida, , Grounds Maintenance, archived from the original on 29 October 2019, retrieved 28 October 2014
  9. ^ "Fertiliser labels explained". RHS Advice. Royal Horticultural Society. Retrieved 31 October 2021.
  10. ^ Bat and seal guano are lower in fertilizer value than bird guano. see Guano
  11. ^ George Rehm; Michael Schmitt; John Lamb; Gyes Randall; Lowell Busman (2002). . University of Minnesota Extension Service. Archived from the original on 5 September 2013. Retrieved 28 October 2014.
  12. ^ a b c from "Average total N, ammonium N, phosphate and potash content of manure at the time of land application" in Animal Manure As a Plant Nutrient Resource, Bulletin ID-101 (Reviewed 02/05/01), Cooperative Extension Service, Purdue University. West Lafayette, IN 47907 . Archived from the original on 12 March 2012. Retrieved 28 October 2014.
  13. ^ Organic Fish, Blood and Bone Feed – Harrod Horticultural (UK) www.harrodhorticultural.com accessed 15 December 2022

February 15, 2024
labeling, fertilizer, redirects, here, other, uses, disambiguation, many, countries, have, standardized, labeling, fertilizers, indicate, their, contents, major, nutrients, most, common, labeling, convention, label, shows, amounts, chemical, elements, nitrogen. NPK redirects here For other uses see NPK disambiguation Many countries have standardized the labeling of fertilizers to indicate their contents of major nutrients 1 2 The most common labeling convention the NPK or N P K label shows the amounts of the chemical elements nitrogen phosphorus and potassium Contents 1 Common labeling conventions 1 1 The NPK analysis label 1 2 Other labeling conventions 2 Converting nutrient analysis to composition 3 NPK values for commercial fertilizers 3 1 NPK values for various synthetic fertilizers 7 3 2 NPK values for mined fertilizer minerals 3 3 NPK values for biosolids fertilizers and others 4 See also 5 ReferencesCommon labeling conventions editThe NPK analysis label edit Fertilizers are usually labeled with three numbers as in 18 20 10 indicating the relative content of the primary macronutrients nitrogen N phosphorus P and potassium K respectively More precisely the first number N value is the percentage of elemental nitrogen by weight in the fertilizer that is the mass fraction of nitrogen times 100 The second number P value is the percentage by weight of phosphorus pentoxide P2 O5 The third number K value is the equivalent content of potassium oxide K2 O 3 For example a 15 13 20 fertilizer would contain 15 by weight of nitrogen 13 by weight of P2 O5 20 by weight of K2 O and 52 of some inert ingredient Other labeling conventions edit In the U K fertilizer labeling regulations allow for reporting the elemental mass fractions of phosphorus and potassium The regulations stipulate that this should be done in parentheses after the standard N P K values as in 15 30 15 15 13 13 4 In Australia macronutrient fertilizers are labeled with an N P K S system which uses elemental mass fractions rather than the standard N P K values and includes the amount of sulfur S contained in the fertilizer 5 Fertilizers with additional macronutrients S Ca Mg may add more numbers to the N P K ratio to indicate the amount The additional numbers are similarly reported in the oxide mass fraction form For example a Polish fertilizer labeled NPK Ca S 4 12 12 14 29 has an equivalent of 14 soluble calcium oxide and 29 total sulfur trioxide 6 Converting nutrient analysis to composition editThe values in an NPK fertilizer label are related to the concentrations by weight of phosphorus and potassium elements as follows P2 O5 consists of 56 4 elemental oxygen and 43 6 elemental phosphorus by weight Therefore the elemental phosphorus percentage of a fertilizer is 0 436 times its P value K2 O consists of 17 oxygen and 83 elemental potassium by weight Therefore the elemental potassium percentage is 0 83 times the K value The N value in NPK labels represents actual percentage of nitrogen element by weight so it does not need to be converted So for example an 18 51 20 fertilizer contains by weight 18 elemental nitrogen 0 436 51 22 elemental phosphorus and 0 83 20 17 elemental potassium As another example the fertilizer sylvite is a naturally occurring mineral consisting mostly of potassium chloride KCl Pure potassium chloride contains one potassium atom whose atomic mass is 39 09 g mol for every chlorine atom whose atomic mass is 35 45 g mol Therefore pure KCl is 39 09 39 09 35 45 52 potassium and 48 chlorine by weight Its K value is therefore 52 0 83 63 that is a fertilizer that gets all its potassium from K2 O and has the same potassium contents as pure KCl would have to be 63 K2 O Pure KCl fertilizer would thus be labeled 0 0 63 Since sylvite contains other compounds that contribute no N P or K it is usually labeled 0 0 60 NPK values for commercial fertilizers editNPK values for various synthetic fertilizers 7 edit 15 0 0 Calcium nitrate 21 0 0 Ammonium sulphate 30 0 0 to 40 0 0 Sulfur coated urea slow release 8 31 0 0 Isobutylidenediurea 90 slow release 8 33 0 0 to 34 0 0 Ammonium nitrate 35 0 0 Ureaform 85 slow release sparingly soluble ureaformaldehyde 8 40 0 0 Methylene ureas 70 slow release 8 46 0 0 Urea U 46 82 0 0 Anhydrous ammonia 10 34 0 to 11 37 0 Ammonium polyphosphate 11 48 0 to 11 55 0 Monoammonium phosphate 18 46 0 to 21 54 0 Diammonium phosphate 7 7 7 Growmore 9 13 0 44 Potassium nitrate 0 17 0 to 0 22 0 Superphosphate Monocalcium phosphate monohydrate with gypsum 0 44 0 to 0 52 0 Triple superphosphate Monocalcium phosphate monohydrate 0 0 22 Potassium magnesium sulfate K mag NPK values for mined fertilizer minerals edit 11 8 2 to 16 12 3 bird guano 10 0 3 0 to 0 8 0 Raw Phosphate Rock would be 0 34 0 if it were soluble 11 0 0 60 Potassium chloride 0 0 19 Kainite 0 0 17 CarnalliteNPK values for biosolids fertilizers and others edit 9 0 0 dairy manure 12 1 0 1 horse manure 12 3 2 2 poultry manure 12 4 12 0 Bone meal 5 5 6 Fish blood and bone 13 6 2 0 MilorganiteSee also editFertilizerReferences edit Chambers Albert Sally Rutherford 27 November 2007 Voluntary Standards for the Fertilizer and Supplements Industry Retrieved 3 February 2010 Draft Code of Practice for Fertilier Description and Labeling Fertilizer Industry Federation Association FIFA 15 September 2008 Retrieved 3 February 2010 nutrient analysiswww flairform com 22 October 2014 Archived 28 October 2014 at the Wayback Machine UK Fertilizers Regulations 1990 Schedule 2 Part 1 Para 7 National Code of Practice for Fertilizer Description amp Labelling PDF Australian Government Department of Agriculture Fisheries and Forestry Archived from the original PDF on 28 February 2015 Retrieved 27 October 2014 NPK Ca S 4 12 12 14 29 Lubofoska skladrolny pl Retrieved 15 December 2022 Lubofoska is a fertilizer applied before sowing NPK Fertilizer chemicalland21 com accessed 15 December 2022 a b c d J B Sartain University of Florida Food for turf Slow release nitrogen Grounds Maintenance archived from the original on 29 October 2019 retrieved 28 October 2014 Fertiliser labels explained RHS Advice Royal Horticultural Society Retrieved 31 October 2021 Bat and seal guano are lower in fertilizer value than bird guano see Guano George Rehm Michael Schmitt John Lamb Gyes Randall Lowell Busman 2002 Understanding Phosphorus Fertilizers University of Minnesota Extension Service Archived from the original on 5 September 2013 Retrieved 28 October 2014 a b c from Average total N ammonium N phosphate and potash content of manure at the time of land application in Animal Manure As a Plant Nutrient Resource Bulletin ID 101 Reviewed 02 05 01 Cooperative Extension Service Purdue University West Lafayette IN 47907 ID 101 Archived from the original on 12 March 2012 Retrieved 28 October 2014 Organic Fish Blood and Bone Feed Harrod Horticultural UK www harrodhorticultural com accessed 15 December 2022 Retrieved from https en wikipedia org w index php title Labeling of fertilizer amp oldid 1201686456, wikipedia, wiki, book, books, library,

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