Common Fertilizers Used in Virginia: Secondary and Micronutrients
ID
SPES-200NP
Introduction
Secondary macronutrients are used in relatively large quantities by plants for optimal growth and are sulfur (S), calcium (Ca), and magnesium (Mg). Micronutrients on the other hand are needed in much smaller quantities than both primary and secondary macronutrients; however, micronutrients are still essential for plant growth. Often, soils in Virginia contain enough micronutrients and fertilizer amendments are not warranted. Micronutrients include iron (Fe), zinc (Zn), copper (Cu), manganese (Mn), boron (B), chloride (Cl), molybdenum (Mo), cobalt (Co), sodium (Na), silicon (Si), selenium (Se), nickel (Ni), and Vanadium (V) (Havlin et al, 1996). Soil pH plays a large role in soil availability of secondary and micronutrients; therefore, proper soil testing and lime amendments are necessary to ensure adequate nutrient solubility within the soil system. Visit the Virginia Tech Soil Testing Lab website for additional publications and resources regarding proper soil sampling techniques and recommendations at: https://www.soiltest.vt.edu/. This publication will outline some possible secondary macronutrient and micronutrient fertilizer sources. However, numerous formulations and blends are available from many different companies and dealers. Regardless of product or source used, read the product’s label carefully and follow all recommendations for foliar and/or soil application.
| Fertilizer Material | Chemical Formula | Nutrient Percent | Other Nutrients (%) |
|---|---|---|---|
| Calcium sources | % Ca | ||
| Calcitic lime | CaCO3 | 31.7 | |
| Calcium nitrate | Ca(NO3)2 | 21.0 | 15% N |
| Dolomitic lime | CaCO3·MgCO3 | 21.5 | 11.4% Mg |
| Gypsum | CaSO4·2H2O | 22.5 | 16.8% S |
| Hydrated lime | Ca(OH)2 | 46.1 | |
| Marl | CaCO3 | 24.0 | |
| Polyhalite | K2SO4·MgSO4·2CaSO4· 2H2O | 12.0 | 14% K2O, 19% S, 4% Mg |
| Superphosphate, normal | Ca(H2PO4)2 | 18-21 | 16-20% P2O5 |
| Superphosphate, triple | Ca(H2PO4)2 | 13-15 | 44-48% P2O5 |
| Sulfur sources | % S | ||
| Ammonium sulfate | (NH4)2SO4 | 24 | 21% N |
| Ammonium thiosulfate | (NH4)2S2O3 | 26 | 12% N |
| Fertilizer Material | Chemical Formula | Nutrient Percent | Other Nutrients (%) |
| Gypsum | CaSO4·2H2O | 16.8 | 22.5% Ca |
| Polyhalite | K2SO4·MgSO4·2CaSO4· 2H2O | 19 | 14% K2O, 19% S, 4% Mg, 12% Ca |
| Potassium magnesium sulfate | K2SO4·2MgSO4 | 22.0 | 22% K2O, 11% Mg |
| Potassium sulfate | K2SO4 | 17-20 | 48-54% K2O |
| Potassium thiosulfate | K2S2O3 | 17 | 25% K2O |
| Sulfur, elemental | S | 90-100 | |
| Urea-sulfur | CO(NH2)2+S | 10-20 | 36-40% N |
| Urea-ammonium nitrate, sulfur blend | Various | 3-5 | 24-28% N |
| Zinc sulfate | ZnSO4·H2O | 17.8 | 36.4% Zn |
| Magnesium sources | % Mg | ||
| Dolomitic lime | MgCO3·CaCO3 | 11.4 | 21.5% Ca |
| Epsom salt | MgSO4·7H2O | 9.6 | 13% S |
| Magnesia | MgO | 55.0 | |
| Polyhalite | K2SO4·MgSO4·2CaSO4· 2H2O | 4 | 14% K2O, 19% S, 12% Ca |
| Potassium magnesium sulfate | K2SO4·2MgSO4 | 11.2 | 22% K2O, 22% S |
| Boron Sources | % B | ||
| Borax | Na2B4O7·10H2O | 11.3 | |
| Sodium octaborate, Borate 65 | Na2B8O13·4H2O | 20-21 | |
| Sodium pentaborate | Na2B10O16·10H2O | 18 | |
| Sodium tetraborate, Borate 46 | Na2B4O7·5H2O | 14-15 | |
| Boric acid | H3BO3 | 17.0 | |
| Boron frits | Frit | 2-11 | |
| Solubor | Na2B4O7·5H2O + Na2B10O16·10H2O | 20-21 | |
| Molybdenum sources | % Mo | ||
| Ammonium molybdate | (NH4)6Mo7O24·2H2O | 54 | 7% N |
| Molybdenum frits | Frit | 1-30 | |
| Molybdenum trioxide | MoO3 | 66 | |
| Sodium molybdate | Na2MoO4·2H2O | 39 | |
| Copper ammonium phosphate | Cu(NH4)PO4·H2O | 32 | 7.2% N, 36.5% P2O5 |
| Copper chelates | NaCuHEDTA | 9 | |
| Copper sources | % Cu | ||
| Copper chelates | Na2CuEDTA | 13 | |
| Copper frits | Frit | 40-50 | |
| Copper sulfate | CuSO4·5H2O | 25.5 | 12.8% S |
| Manganese sources | % Mn | ||
| Manganese chelate | MnEDTA | 12 | |
| Manganese frits | Frit | 10-35 | |
| Manganese oxide | MnO | 41-68 | |
| Manganese sulfate | MnSO4·4H2O | 26-28 | 14.4% S |
| Zinc sources | % Zn | ||
| Zinc carbonate | ZnCO3 | 52 | |
| Zinc chelates | NaZnHEDTA | 9 | |
| Zinc chelates | Na2ZnEDTA | 14 | |
| Zinc oxide | ZnO | 78 | |
| Zinc phosphate | Zn3(PO4)2 | 51 | 18.4% P2O5 |
| Zinc sulfate | ZnSO4·H2O | 35 | 17.9% S |
| Iron Sources | % Fe | ||
| Iron ammonium phosphate | Fe(NH4)PO4·H2O | 29 | 7.5% N, 38% P2O5 |
| Iron ammonium polyphosphate | Fe(NH4)HP2O7 | 22 | 5.6% N, 57% P2O5 |
| Iron chelates | NaFeEDTA | 5-14 | |
| Iron chelates | NaFeEDDHA | 6 | |
| Iron chelates | NaFeDTPA | 10 | |
| Iron frits | Frit | 30-40 | |
| Iron sulfate, Ferrous sulfate | FeSO4·7H2O | 19 | 11.5% S |
References
Alley, M.M. 2000. “Part VIII: Fertilizers.” Agronomy Handbook. Publication 424-100. Virginia Cooperative Extension, Blacksburg.
Gowariker, V. 2009. “The Fertilizer Encyclopedia.” John Wiley & Son, Inc., Hoboken, New Jersey. Havlin, J.L.,
J.D. Beaton, S.L. Tisdale, and W.L. Nelson. 1999. “Soil Fertility and Fertilizers, 6th Edition.” Prentice Hall, Upper Saddle River, New Jersey.
International Plant Nutrition Institute. 2015. “Boron.” Last Accessed April 8, 2020.
http://anz.ipni.net/article/ANZ-3234
International Plant Nutrition Institute. 2019. “Nutrient Source Specifics.” Last Accessed April 3, 2020. http://www.ipni.net/specifics-en
Sirius Minerals, LTD. 2019. “POLY4 Granular Product Specification Sheet.” Last Accessed April 2, 2020. https://www.poly4.com/site/assets/files/1224/granular_specifcation_sheet_-_october_19.pdf
Binford, G.D. 2006. “Chapter 8: Commercial Fertilizers.” The Mid-Atlantic Nutrient Management Handbook. Publication MAWP-0602. Last Accessed April 3, 2020. https://extension.psu.edu/programs/nutrient-management/educational/nutrient-management-general/mid-atlantic-nutrient-management-handbook
Acknowledgments
Funding for this work was provided in part by the Virginia Agricultural Experiment Station and the Hatch program of the National Institute of Food and Agriculture, US Department of Agriculture.
Virginia Cooperative Extension materials are available for public use, reprint, or citation without further permission, provided the use includes credit to the author and to Virginia Cooperative Extension, Virginia Tech, and Virginia State University.
Virginia Cooperative Extension is a partnership of Virginia Tech, Virginia State University, the U.S. Department of Agriculture, and local governments. Its programs and employment are open to all, regardless of age, color, disability, sex (including pregnancy), gender, gender identity, gender expression, genetic information, ethnicity or national origin, political affiliation, race, religion, sexual orientation, or military status, or any other basis protected by law.
Publication Date
April 10, 2020
