What is a micronutrient?

Photo Credit: https://www.agronomy.k-state.edu/extension/soil-fertility/nutrient-deficiencies/index.html

Micronutrients (sometimes also called trace elements) are essential plant nutrients required in very small amounts to sustain plant growth and development, especially enzyme systems related to photosynthesis and respiration. The main essential elements in this group usually include boron, chlorine, copper, iron, manganese, molybdenum, nickel, and zinc.

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Regional Educator ResourcesOther Educator ResourcesTechnical Resources
Title Source Resource type and Date Short Summary / Preview
Micro- and secondary macronutrients University of Minnesota Extension Webpage

Not Dated

While micro and secondary nutrients are not as essential as the Macronutrients N,P, and K; these are nutrients key to Minnesota farmers in some geographical regions, soils, crops grown and management practices used. The nutrients Boron, Copper, Sulfur, Magnesium, and Zinc are in this category. This publication links to a guide for each that describes each nutrient and provides information such as: availability and deficiencies in Minnesota soils, the nutrients’ roles in plant functions, causes and symptoms of deficiencies, requirements of nutrients, plant responses to nutrient applications and sources of nutrients.
Role of Micronutrients in Efficient Crop Production Purdue University Extension Publication

Jul 1990

This resource discusses the micronutrients needed by field crops in Indiana, approximate micronutrient uptake by corn, soybeans and alfalfa, diagnosing micronutrient deficiencies and plant sampling guide for diagnosing micronutrient deficiencies. It then explains in what soil types and locations in Indiana and in what crops, micronutrient deficiencies are most likely to occur and how to correct them.
Manganese Deficiencies in Indiana Soils Purdue University Extension Publication

Jul 2003

As a micronutrient, manganese is needed in small amounts for normal growth of all crops.  This publication reviews how to recognize manganese deficiency, soil testing and plant analysis for manganese as well as corrective measures.
Zinc Deficiency in Corn Purdue University Extension Publication

Jun 2012

This publication from Indiana explains the symptoms of zinc deficiency in corn, tissue sampling procedures of corn to measure potential zinc deficiencies and factors affecting zinc deficiencies. The resource also explains soil testing to identify zinc deficiency, how to correct it and different zinc fertilizers and application methods that can be practiced.
Striped Corn – Potential Nutritional Deficiencies Purdue University Extension Publication

Jun 2013

This two-page Purdue University fact-sheet publication provides colored photos for identifying potential corn nutrient deficiencies. Photos of yellow to white colored leaf veins illustrate: sulfur (S); zinc (Zn); magnesium (Mg) and manganese (Mn) deficiency visual signs.
Wheat Production and Fertilization in Indiana Purdue University Extension Publication

Nov 1992

This publication is directed at helping Indiana producers achieve optimum wheat yields by discussing varieties, planting dates, seeding rates, fertilization and other management practices.
Nutrient Deficiencies Kansas State University University Webpage

Not Dated

This is a gallery of photos of nutrient deficiencies for common row crops.
Micronutrients Kansas State University Extension Training Manual

Not Dated

This is a section from an extension handbook. This section is on micronutrients for common row crops.
Micronutrient Management Kansas State University Presentation

Dec 2019

This is a slide set developed and used for extension training purposes. It contains information on zinc, iron, boron, copper, manganese, molybdenum, chlorine, and nickel, with particular respect to the amounts needed for producing row crops.
Diagnosing Nutrient Deficiencies in the Field Kansas State University Extension Publications

Aug 2011

This publication discusses nutrient deficiencies and provides good visuals to help diagnose nutrient deficiencies.
Healthy Soils Produce Healthy Crops SARE Extension/Government Webpage

not dated

Low quantities of nutrients, high levels of such toxic elements as aluminum and high concentrations of salts can adversely affect the growth of your crops.
Other Nutrients SARE Book Excerpt


Although farmers understandably focus on nitrogen and phosphorus—because of the large quantities used and the potential for environmental problems—additional nutrient and soil chemical issues remain important.
Title Source Resource type and date Short Summary
Soil Nutrient Management For Forages: Phosphorus, Potassium, Sulphur, and Micronutrients Montana State University Extension Publication


Improvements in forage production have the potential to increase income and significantly reduce livestock production costs. Soil fertility is important for forage production, stand health/longevity, and forage quality.
Title Source Resource type and Date Short Summary
Strategies for Increasing Micronutrient Availability in Soil for Plant Uptake (Chapter 11 of Plant Micronutrient Use Efficiency) Academic Press Book Chapter


This abstract links to the ScienceDigest Journal book, “Plant Micronutrient Use Efficiency.” Chapter 11 authored by Tsugiyuki Masunaga and Juan D. Marques Fong. Micronutrient update by plants is summarized while also identifying the complex molecular micronutrient mechanisms.
Zinc in Soil Environment for Plant Health and Management Strategy Universal Journal of Agricultural Research Peer-reviewed Publication


Under severe zinc deficiency the shoot apices die (‘die-back’) as is widely distributed. Zinc toxicity leads to chlorosis in young leaves.
Soil factors associated with zinc deficiency in crops and humans Environmental Geochemistry and Health Peer-reviewed Publication

Oct 2009

This is a brief abstract from the Environ Geochem Health publication authored by BJ Alloway from the University of Reading – UK.  Zinc deficiency is highlighted as a potential nutrient problem in plants & humans worldwide.
Patterns of Soil Calcium and Aluminum Across the Conterminous United States (Chapter 9 of Forest Health Monitoring: 2008 National Technical Report) U.S. Department of Agriculture Forest Service Book Chapter

Jun 2012

Low concentrations of aluminum (Al) (<1 mg/l) can stimulate plant growth and may act as a fungicide, but Al is a cation generally considered to have negative effects on plants. The toxic effects of Al include the inhibition of root growth and reduced uptake of several key cations (phosphorus, magnesium, and Ca).

Technical review: March 18, 2020