ASSOCIATION OF AMERICAN PLANT FOOD CONTROL OFFICIALS (AAPFCO)  OFFICIAL FERTILIZER DEFINITIONS NITROGEN PRODUCTS (N)

 

N-9 — Acidulated Fish Tankage (acidulated fish scrap)

Is the rendered product derived from fish and treated with sulfuric acid.
(Official 1950)

N-10 — Activated Sewage Products

Are those made from sewage freed from grit and coarse solids and aerated after being inoculated with microorganisms. The resulting flocculated organic matter is withdrawn from the tanks, filtered with or without the aid of coagulants, dried, ground, and screened.
(Official 1950)

N-44 — Alfalfa Meal

Is produced from alfalfa which has been mowed, chopped, dried, and ground.
(Official 2005)

N-39 — Amino urea formaldehyde

Definition deleted.
(Official 2002)

N-71 — Amino Acids

Are a recognized source of nitrogen and the basic structural units of proteins. They consist of an amino group, a carboxyl group, hydrogen atoms, and a distinctive side group.
(Official 2014)

N-70 — Ammonium Bicarbonate

The bicarbonate salt of the ammonium ion with the chemical formula of (NH₄)HCO₃. It shall contain not less than 17% total nitrogen. CAS# 1066-33-7. In its solid form ammonium bicarbonate is water soluble.
(Tentative WA 2019, Official WA 2020)

N-68 — Ammonium Calcium Nitrate Double Salt

Is a fertilizer-grade hydrated double salt (calcium nitrate and ammonium nitrate) formulated from nitric acid. It is a prill or granular dry product and is a single water-soluble compound but not a mixture/blend of multiple sources. This product shall contain a minimum of 15.0% nitrogen and 18.5% calcium and at least 12% water of crystallization. It has less than 10% ammonium nitrate by weight. It is further identified by CAS# 15245-12-2.
(Tentative WA 2019, Official WA 2020)

N-73 — Ammonium Citrate

Ammonium citrates are the ammonium salts of citric acid. Depending on the mole ratios of citric acid and ammonia, ammonium citrate salts could be mono-ammonium citrate (C₆H₁₁NO₇; N = 7.7%), di-ammonium citrate (C₆H₁₄N₂O₇; N = 12.3%), or tri-ammonium citrate (C₆H₁₇N₃O₇; N = 17%). They can serve as sources of nitrogen and as complexing agents of metallic cations.
(Tentative SA 2024)

N-1 — Ammoniated Superphosphate

Is a product obtained when superphosphate is treated with ammonia or with solutions which contain ammonia and other compounds of nitrogen. The guaranteed percentages of nitrogen and of available phosphate shall be stated as part of the name. 
(Official 1993)

N-2 — Ammonium Nitrate

Is chiefly the ammonium salt of nitric acid. It shall contain not less than thirty-three percent (33%) nitrogen, one-half of which is in the ammonium form and one-half in the nitrate form.
(Official 1951)

N-54 — Ammonium Nitrate-Sulfate

Is a blend of ammonium nitrate and ammonium sulfate. The nitrogen content is typically between 26–30%.
(Official 2013)

N-38 — Ammonium Phosphite

Is a product obtained when phosphorous acid is neutralized with ammonium hydroxide (aqueous) and consists primarily of diammonium phosphite [(NH₄)₂PO₃] in a stable aqueous solution. The phosphorus atom is in the oxidation state of III. It does not contain any significant amount of available phosphate.
(Official 2002)

N-55 — Ammonium Polysulfide

Is a mixture of ammonium polysulfides formed by reacting ammonium hydroxide and sulfur. The nitrogen content is not less than 2% and sulfur content is typically between 40–45%.
(Official 2013)

N-8 — Ammonium Sulfate Nitrate

Is a double salt of ammonium sulfate and ammonium nitrate which are present in equal molecular proportions. It shall contain not less than twenty-six percent (26%) nitrogen, one- fourth of which is in nitrate form and three-fourths in the ammonium form.
(Official 1954)

N-37† — Ammonium Thiosulfate (fertilizer quality)

Is a commercial product composed principally of (NH₄)₂S₂O₃. The guaranteed percentages of nitrogen and sulfur shall be stated as part of the name. It is a nitrification inhibitor.
(Official 2000)

N-52 — Anhydrous Ammonia

Is ammonia gas with the water content less than 0.5%, which is in a liquid form under pressure. The nitrogen concentration is typically 82%.
(Official 2013)

N-14 — Animal Manures

Are the excreta of animals together with whatever bedding materials are needed to follow good dairy barn, feedlot, poultry house, etc., practice in order to maintain proper sanitary conditions.
(Official 1991)

N-53 — Aqua Ammonia

Is a solution of ammonia and water. The nitrogen content is typically between 10–30%.
(Official 2013)

N-11 — Bat Guano

Is partially decomposed bat excrement. Bat guano has an organic matter content greater than 40%, is a source of nitrogen, and may contain up to 6% available phosphate (P₂O₅).
(Tentative WA 2017, Official SA 2017)

N-46 — Brewers Grains

Are the dried extracted residues of barley malt and/or other cereal grains from the manufacture of wort or beer.
(Official 2005)

N-45 — Brewers Yeast

Is the dried non-fermenting, non-extracted yeast of the botanical classification Saccharomyces, resulting as a byproduct from the brewing of beer and ale.
(Official 2005)

N-67 — Calcium Ammonium Nitrate

A dry fertilizer prill or granular containing as essential ingredients only ammonium nitrate and calcium carbonate (e.g., limestone) and/or magnesium carbonate and calcium carbonate (e.g., dolomite), prepared as a homogeneous mixture, with a maximum combustible material content, expressed as organic carbon, of 0.4% by weight. The minimum content of such calcium and/or magnesium carbonates in this product is 20% by weight and their purity level is 90% by weight minimum. The calcium in this product is not water-soluble.
(Tentative WA 2019, Official WA 2020)

N-3 — Calcium Nitrate (fertilizer quality)

Is chiefly the hydrated calcium salt of nitric acid. It shall contain not less than twelve percent (12%) nitrate nitrogen.
(Official 1999)

N-69 — Calcium Nitrate

Is the calcium salt of nitric acid; this product shall not contain an ammonium ion. It encompasses both the anhydrous form (CAS# 10124-37-5) and the hydrated form (CAS# 13477-34-4) of the salt.
(Tentative WA 2019, Official WA 2020)

N-56 — Calcium Nitrate-Urea

Definition deleted.
(Official 2015, SA)

N-41 — Corn Gluten Meal

Is the dried residue from corn after the removal of the larger part of the starch, germ, and bran.
(Official 2003)

N-72 — Corn Steep Liquor

A water-soluble by-product of corn wet milling. It may be produced by soaking cleaned shelled corn in dilute sulfur dioxide solution, followed by corn solids removal and concentration of the steep water by evaporation. The resulting corn steep liquor is a source of nitrogen, available phosphate, and soluble potash.
(Tentative WA 2020, Official SA 2021)

N-48 — Cottonseed Meal

Definition deleted. See N-61.
(Official 2016, SA)

N-22‡ — Crude, Inert, or Slow-Acting Nitrogenous Materials

Are unprocessed organic substances relatively high in nitrogen but having a very low value as plant food and showing a low activity by both the alkaline and neutral permanganate methods (below 50% and 80% respectively).
(Official 1964)

N-12‡ — Cyanamide (Lime Nitrogen)

Is a commercial product consisting principally of calcium cyanamide (CaCN₂). It is a nitrification inhibitor.
(Official 2002)

N-31‡ — Dicyandiamide (cyanoguanidine)

Is a water-soluble organic compound of formula C₂H₄N₄ which contains at least sixty-five percent (65%) nitrogen. It is a source of slowly available nitrogen. It is a nitrification inhibitor.
(Official 2000)

N-30‡ — Dimethylenetriurea (DMTU)

Is a water-soluble condensation product resulting from the reaction of two molecules of formaldehyde with three molecules of urea, with the elimination of two molecules of water, and having a minimum total nitrogen content of forty-one percent (41%). It is a source of slowly available nitrogen.
(Official 1984)

N-50 — Distillers Grains

Is obtained after the removal of ethyl alcohol by distillation following the yeast fermentation of a grain or grain mixture by separating the resultant coarse grain fraction of the whole stillage by methods employed in the grain distilling industry.
(Official 2011)

N-13 — Dried Blood

Also known as Blood Meal, is the collected blood of slaughtered animals, dried and ground and containing not less than twelve percent (12%) nitrogen.
(Tentative 2015, WA), (Official 2015, SA)

N-58 — Ferric Ammonium Sulfate

Also known as Ammonium Iron (III) Sulfate FeNH₄(SO₄)₂, which is a double salt of ferric sulfate and ammonium sulfate.
(Official 2013)

N-62† — Feather Meal

A product from poultry processing, consisting of ground and processed (hydrolysis, pressure, heat and/or other methods that aid in nutrient availability and provide pathogen reduction) bird feathers.
(Tentative WA 2018, Official SA 2018)

N-57 — Ferrous Ammonium Sulfate

See Fe-19.
(Official 2015, SA)

N-18 — Fish Tankage (fish scrap, dry ground fish, fish meal)

Is the dried ground product derived from rendered or unrendered fish.
(Official 1950)

N-15 — Garbage Tankage

Is the rendered, dried, and ground product derived from waste household food materials.
(Official 1951)

N-16 — Hoof and Horn Meal

Is processed dried, ground hoofs and horns.
(Official 1951)

N-65 — Hydrolyzed Feather Meal

Definition deleted.
(Official 2016, SA)

N-26‡ — Isobutylidene Diurea

Is a condensation product of isobutyraldehyde and urea having a minimum total nitrogen content of thirty percent (30%). It is a source of slowly available nitrogen by virtue of particle size, solubility decreasing with increase in particle size. Material conforming to the description of a “granular fertilizer” will have ninety percent (90%) of its nitrogen content in the water insoluble form prior to grinding as tested by AOAC International Method 945.01 (15th Edition).
(Official 1986)

N-51 — Kapok Seed Meal

Definition deleted. See N-61.
(Official 2015, SA)

N-59 — Magnesium Nitrate

Is the magnesium salt of nitric acid – Mg(NO₃)₂·6H₂O, with a minimum nitrogen concentration of 10.5% and a minimum magnesium concentration of 9.3%.
(Official 2013)

N-34 — Melamine

Definition deleted.
(Official 2011)

N-40‡ — Methylene Urea(s) (MU, polymethylene urea(s))

Is a product obtained by the reaction of urea with formaldehyde and contains oligomers of urea bonded together by methylene (-CH₂-) linkages. It is chiefly composed of cold-water soluble fractions from methylenediurea (MDU) and dimethylenetriurea (DMTU), hot-water soluble fractions from trimethylenetetraurea (TMTU) and tetramethylene pentaurea (TMPU), and hot-water insoluble fractions from longer chain oligomers. It is generally free of methylureas and methyl ethers. It is a source of slowly available nitrogen.
(Official 2001)

N-29‡ — Methylenediurea (MDU)

Is a water-soluble condensation product resulting from the reaction of one molecule of formaldehyde with two molecules of urea, with the elimination of one molecule of water. It has a minimum total nitrogen content of forty-two percent (42%) and is a source of slowly available nitrogen.
(Official 1984)

N-4 — Nitrate of Potash (potassium nitrate)

Is chiefly the potassium salt of nitric acid. It shall contain not less than twelve percent (12%) nitrogen and forty-four percent (44%) soluble potash.
(Official 1951)

N-5 — Nitrate of Soda

Is chiefly the sodium salt of nitric acid. It shall contain not less than sixteen percent (16%) nitrate nitrogen and twenty-six percent (26%) sodium.
(Official 1952)

N-6 — Nitrate of Soda and Potash (sodium and potassium nitrate)

Is chiefly the sodium and potassium salts of nitric acid. It shall contain not less than fifteen percent (15%) nitrate nitrogen, ten percent (10%) soluble potash and eighteen percent (18%) sodium.
(Official 1952)

N-43 — Nitrophosphate

Is the product obtained by acidulation of phosphate rock with nitric acid. The complex mixture of nitrates and phosphate thus obtained does not contain nitrate nitrogen and phosphorus in the same molecule. The process is subject to modification designed to remove the hygroscopic calcium nitrate formed. Such modifications include ammoniation, physical separation, co-acidulation with sulfuric or phosphoric acids, or subsequent treatment with carbon dioxide.
(Official 1974)

N-61 — Oilseed Meal

Is the product remaining after extracting most of the oil from whole oilseed. It is a source of slowly available nitrogen. The definition is used by prefixing the term “meal” with the name of the whole oilseed from which the meal is derived (e.g. soybean meal, cottonseed meal, mustard seed meal, etc.).
(Official 2014)

N-36‡ — Oxamide (fertilizer quality)

Is the diamide of oxalic acid of the formula C₂H₄N₂O₂ which contains twenty-eight to thirty- two percent nitrogen (28%–32%). It is a source of slowly available nitrogen.
(Official 1990)

N-17 — Peat

Moved. See PMP-12.

N-32‡ — Polymer Coated Urea (PCU)

Is a coated slow-release fertilizer consisting of urea particles coated with a polymer (plastic) resin. It typically contains about forty percent (40%) nitrogen. It is a source of slowly available nitrogen.
(Official 1990)

N-19‡ — Process Tankage

Is a product made under steam pressure from crude inert nitrogenous materials, with or without the use of acids or bases, for the purpose of increasing the activity of nitrogen. These products shall be called “Process Tankage” with or without further qualification. The water insoluble nitrogen in these products shall test at least fifty percent (50%) active by the alkaline, or eighty percent (80%) by the neutral permanganate method.
(Official 1994)

N-42 — Protein Hydrolysate

Is the organic material obtained by the hydrolysis of proteins to their constituent amino acids and short polypeptides. They are a source of nitrogen. The definition is used by prefixing the term with the name of the protein from which the hydrolysate is derived. Examples include Fish Protein Hydrolysate or Soy Protein Hydrolysate.
(Tentative 2015, SA; Official 2016, WA)

N-21 — Sheep Manure Wool Waste

Is the by-product from wool-carding establishments consisting chiefly of sheep manure, seeds, and wool fiber.
(Official 1951)

N-47 — Soybean Meal

Definition deleted. See N-61.
(Official 2016, SA)

N-7 — Sulfate of Ammonia (ammonium sulfate)

Is chiefly the ammonium salt of sulfuric acid. It shall contain not less than twenty and five-tenths percent (20.5%) nitrogen.
(Official 1951)

N-27‡ — Sulfur Coated Urea (SCU)

Is a coated slow-release fertilizer consisting of urea particles coated with sulfur. The product is usually further coated with a sealant (2% to 3% of total weight) and a conditioner (2% to 3% of total weight). It typically contains about thirty percent (30%) to forty percent (40%) nitrogen and about ten percent (10%) to thirty percent (30%) sulfur.
(Official 1980)

N-20 — Tankage

Also known as Meat & Bone Meal, is the rendered, dried, and ground by-product, largely meat and bone from animals (slaughtered or that have died otherwise).
(Tentative 2015, WA; Official 2015, SA)

N-33‡ — Triazone

Is a water-soluble compound of formula C₅H₁₁N₅O₂ [5-(N-methyl)-urea-1,3,5-triazin-2-one] which contains at least forty percent (40%) total nitrogen. It is a source of slowly available nitrogen.
(Official 1989; Secretary’s note: last sentence added 2012)

N-64 — UAN/Calcium Solutions

Manufactured as liquid mixtures of UAN solution and water-soluble calcium solutions containing calcium chloride or calcium nitrate. If sufficient water-soluble calcium is added to produce a calcium-to-urea nitrogen ratio equal to or greater than 0.2, the resulting product can be considered an enhanced efficiency fertilizer since the soluble calcium mitigates ammonia volatilization loss when compared to UAN, the enhancing efficiency reference product standard. 
(Tentative 2016, WA; Official 2016, SA)

N-23 — Urea

Is the commercial synthetic acid amide of carbonic acid and it shall contain not less than forty- five percent (45%) nitrogen.
(Official 1966)

N-60 — Urea Ammonium Nitrate Solution (UAN-x)

Is a commercial liquid product composed of a mixture of ammonium nitrate, urea, and water. The Guaranteed Total Nitrogen content of the product shall be denoted by “x”. Typical UAN products contain between 28–32% Total Nitrogen.

N-49 — Urea Phosphite

Is a liquid product formed by processing a mixture of urea and phosphorous acid. Typically the product contains twenty percent (20%) urea nitrogen. The phosphorus atom is in the oxidation state III and does not contain any significant amount of available phosphate.
(Official 2007)

N-24‡ — Ureaform Fertilizer Materials (sparingly soluble)

Are reaction products of urea and formaldehyde which contain at least thirty-five percent (35%) nitrogen, largely insoluble but slowly available form. The water insoluble content shall be at least sixty percent (60%) of the total nitrogen. The water insoluble nitrogen in these products shall have an activity index of not less than forty percent (40%) when determined by the appropriate AOAC International method.
(Official 1984)

N-25‡ — Urea-Formaldehyde Products (sparingly soluble)

Are reaction products of urea and formaldehyde which contain less than thirty-five percent (35%) nitrogen, largely insoluble but slowly available form. They shall have the percentage of total nitrogen as part of the product name; for example: 20% N Urea-Formaldehyde. The water insoluble nitrogen (AOAC Int. Method 945.01) shall be at least sixty percent (60%) of the total nitrogen. The activity index of the water insoluble nitrogen shall be either: 
(1) not less than forty percent (40%) by the AOAC International method for urea-formaldehyde products (#955.05), or
(2) not less than fifty percent (50%) by the AOAC International alkaline permanganate method (#920.07) or eighty percent (80%) by the neutral permanganate method (#920.06).
(Official 1984)

N-28 — Urea-Formaldehyde Products (water soluble)

Are reaction products of urea and formaldehyde which contain at least thirty percent (30%) nitrogen, largely in water soluble form. Some slowly available nitrogen products are present. Stable aqueous solutions may be prepared from these materials. The reaction products shall contain a maximum of fifty-five percent (55%) free urea, with the remainder of the urea being chemically combined as methylolureas, methylolurea ethers, and/or methylenediurea (MDU) and dimethylenetriurea (DMTU).
(Official 1984)

N-35‡ — Urea-Triazone Solution

Is a stable solution resulting from controlled reaction in aqueous medium of urea, formaldehyde, and ammonia which contains at least twenty-five percent (25%) total nitrogen. The solution shall contain no more than forty percent (40%) nor less than five percent (5%) of total nitrogen from unreacted urea and not less than forty percent (40%) from triazone. All other nitrogen shall be derived from water-soluble, dissolved reaction products of the above reactants. It is a source of slowly available nitrogen.
(Official 1990)

N-63 — Wheat Middlings

Consisting of fine particles of wheat bran, wheat shorts, wheat germ, wheat flour, and offal obtained in the process of commercial wheat milling.
(Official 2015, SA)