Essential Nutrients
   Thirteen essential nutrients
    –Nitrogen, phosphorus, potassium, calcium, 
     magnesium, sulfur
    –Iron, manganese, boron, molybdenum, 
     copper, zinc, and chlorine
     •Nickel has recently been added
   Micros are needed in much lower 
    concentrations to ensure adequate 
    supply
     Essential Micronutrients
     Essential Micronutrients
    Minor elements or trace elements
    Minor elements or trace elements
    Increased interest in micronutrients
    Increased interest in micronutrients
      Higher crop yields and micronutrient removal rates
      Higher crop yields and micronutrient removal rates
      Declining soil organic matter, a major source of 
      Declining soil organic matter, a major source of 
      most micronutrients
      most micronutrients
      N, P and K fertilizers contain lower amounts of 
      N, P and K fertilizers contain lower amounts of 
      micronutrient impurities
      micronutrient impurities
    Excessive levels can cause toxic effects on plants
    Excessive levels can cause toxic effects on plants
    In Kansas: S, Zn, Fe, and Cl.
    In Kansas: S, Zn, Fe, and Cl.
     Other micronutrients: B, Mg, Cu, Mn, and Ni.
     Other micronutrients: B, Mg, Cu, Mn, and Ni.
         Organic Matter
         Organic Matter
  Important source of most micronutrients.
    Important source of most micronutrients.
  Simple organic compounds as chelates.
    Simple organic compounds as chelates.
  S, Zn and B deficiencies are more likely to 
    S, Zn and B deficiencies are more likely to 
   occur in soils low in O.M.
    occur in soils low in O.M.
  Deficiencies of Cu and Mn are most 
    Deficiencies of Cu and Mn are most 
   common in peat soils. 
    common in peat soils. 
             Soil pH
              Soil pH
  Soil pH affects availability of 
    Soil pH affects availability of 
   micronutrients.
    micronutrients.
  In general the solubility and availability of 
    In general the solubility and availability of 
   micronutrients are greatest in acid soils 
    micronutrients are greatest in acid soils 
   and lowest in high pH calcareous soils.
    and lowest in high pH calcareous soils.
  Exception is Mo.
    Exception is Mo.
  In some soils, high levels of soluble Fe, Al 
    In some soils, high levels of soluble Fe, Al 
   and Mn may be toxic to plants.
    and Mn may be toxic to plants.
                Sulfur (S)
                Sulfur (S)
                                     Brian Lang, IA