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Extension » Agronomy Guide » Crop and Soil Management » Tables » Table 1.2-11. Description of fertilizer materials

Table 1.2-11. Description of fertilizer materials

**Table 1.2-11. Description of fertilizer materials.**
Fertilizer	Total N, %	Available phosphoric acid, %	Soluable potash, %	Equivalent acidity ¹	Salt index ²	Comments
Pounds of calcium carbonate equivalent per pound of fertilizer material. Positive numbers indicate that the material increases soil acidity, that is, lowers soil pH. Negative numbers indicate that the material reduces acidity, that is, raises soil pH. Salt index of equal weights of the fertilizer material compared to sodium nitrate, which equals 100. Useful for comparing the salt effect of different fertilizer materials.
Anhydrous ammonia—NH₃	82	0	0	148	47	A high-pressure liquid that turns into a gas when released. Must be injected 6–8 inches deep on friable, moist soil. N loss by volatilization can occur if not properly injected, or if soil is too wet or too dry at application.
Urea—NH₂-CO-NH₂	46	0	0	0.84	75	A dry material in granular or prilled form, urea-N rapidly hydrolyzes to NH_4⁺. Can be used for direct application, in mixed fertilizers, and in liquid nitrogen. N at application is present as urea-N. Within 1 day after application, about 66% of urea-N is hydrolyzed to ammonia-N; all within 1 week. When not incorporated, significant N loss by volatilization can occur until approximately 0.5 inch of rain has fallen. Not recommended for starter use. Broadcast (incorporated) or sidedress.
Ammonium nitrate—NH₄NO₃	33–34	0	0	0.63	105	A dry material in granular or prilled form, in which half of the N is as nitrate and half is as ammonium. Used for direct application and in the production of nitrogen solutions (see below). Broadcast or sidedress. Can be left on surface or incorporated into soil. Ammonium nitrate is a good fertilizer but it can be very difficult to get because it is used as an explosive.
Nitrogen solutions (UAN)—Urea+NH₄NO₃+Water	28–32 (mostly 30 in	0	0	0.54	74	A mixture of ammonium nitrate, urea, and water. Urea supplies about half of the N that may be subject to volatilization loss—read comments above for urea. The other half of N is supplied by ammonium nitrate—read comments above for ammonium nitrate. Once applied, nitrogen solution behaves exactly like dry urea and ammonium nitrate. To minimize N loss, incorporate into soil as soon as possible after application. Use caution when spraying, as leaf burn can occur. To minimize injury, do not spray on vegetation. For postemergence application, use a directed spray or dribble between the rows.
Ammonium sulfate—(NH₄)₂SO₄	21	0	0	1.12	69	A dry crystalline material in which the nitrogen is all in the ammonium form. Produced by two methods—by-product and synthetic. Used for direct application and blended complete fertilizers. Broadcast or sidedress. Can be left on surface or incorporated into soil. Contains 24% sulfur. Good starter N source.
Diammonium phosphate (DAP)—(NH₄)₂HPO₄	18	46	0	0.74	34	A dry granular or crystalline material. Common analysis is 18-46-0. Used for direct application and in blended fertilizers. Starter fertilizers containing DAP should be used with caution; be sure to band at least 2 inches to the side and 2 inches below seed.
Monoammonium phosphate (MAP)—NH₄H₂PO₄	11	52	0	0.65	30	A dry granular material. Common analysis 11-52-0. Used for direct application and in blended fertilizers. Makes an excellent starter fertilizer, either alone or with a small amount of potash.
Ammonium polyphosphate	10	34	0	0.53	-	A liquid solution (10-34-0). The agronomic effectiveness of APP is similar to that of MAP. Sequesters some micronutrients and impurities in fluid fertilizers, keeping them in solution.
Triple superphosphate—Ca(H₂PO₄)₂	0	46	0	0	10	Dry granular material. Used for direct application and in blended fertilizers.
Muriate of potash—KCl	0	0	60–62	0	116	Dry granular material. Used for direct application and in blended fertilizers.
Potassium sulfate—K2SO4	0	0	50	0	46	Dry crystalline material. A specialty fertilizer used for direct application and in blended fertilizers.
Potassium nitrate—KNO₃	13	0	45	-0.26	74	Dry crystalline material. A specialty fertilizer used for direct application and in blended fertilizers.
Potassium hydroxide—KOH	0	0	70	-0.89	-	Crystalline material usually used in liquid fertilizers. Basic nature of this material allows production of neutral liquid fertilizers. Primarily used in liquid starter fertilizers.
Sulfate of potash magnesia— Sul-Po-Mag or K-Mag	0	0	22	-	-	Crystalline material made from langbeinite. Contains 22% sulfur and 11% magnesium.

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