Chapter 12 - Plant Nutrition

Essential Plant Elements Primary Macronutrients - Nitrogen (N) - Phosphorus (P) - Potassium (K) Secondary Macronutrients - Calcium (Ca) - Magnesium (Mg) - Sulfur (S) Micronutrients - Iron (Fe) - Copper (Cu) - Zinc (Zn) - Boron (B) - Molybdenum (Mo) - Manganese (Mn) - Nickel (Ni) - Chlorine (Cl)

Nitrogen Functions: - component of chlorophyll, proteins and nucleic acids - responsible for vegetative growth deficiency symptoms (stunting, chlorosis) General Information: - mobile within plant - ionic forms: NH 4 +, NO 3 -

Nitrogen Cycle

Nitrogen in the Soil very mobile and active form is highly dependent upon microbes Organic N Inorganic N NH 4 + Inorganic N NO 3 - nitrification (warm, MWD, neutral pH soils) immobilization mineralization (wet soils) denitrification leaching atmosphere

Phosphorus Functions: - the “energy” element - needed for good root development, flowering and fruiting - component of cell membranes deficiency symptom (purplish coloration) General Information: - mobile within plant - ionic forms: HPO 4 -2, H 2 PO 4 -

Potassium Functions: - helps regulate stomatal opening/closing - needed to prevent lodging (stem toppling) - improves disease resistance deficiency symptom (marginal scorching) General Information: - mobile within plant - ionic form: K +

Calcium Functions: - component of cell walls and membranes - needed for apical (tip) growth of roots and shoots deficiency symptom (blossom end rot) General Information: - immobile within plant - ionic form: Ca +2

Magnesium Functions: - component of chlorophyll - assists in activating various enzyme systems deficiency symptom (interveinal chlorosis) General Information: - mobile within plant - ionic form: Mg +2

Sulfur Functions: - component of several amino acids - responsible for the pungent flavors of many crops deficiency symptoms (stunting, chlorosis) General Information: - variable mobility within plant - ionic form: SO 4 -2

Iron Functions: - needed for chlorophyll production - involved in various reactions in photosynthesis deficiency symptom (interveinal chlorosis) General Information: - immobile within plant - ionic forms: Fe +2, Fe +3

Nickel Functions: - needed for urea metabolism (form of N) - especially important for legume crops deficiency symptoms (leaf tip necrosis, deformed leaves - “mouse-ear”) General Information: - mobile within plant - ionic form: Ni +2

Zinc Functions: - assists in activating various enzyme systems deficiency symptoms (interveinal chlorosis, shortened internodes) General Information: - immobile within plant - ionic forms: Zn +2

Manganese Functions: - needed for chlorophyll production - needed for nitrogen metabolism deficiency symptoms (interveinal chlorosis, brownish-black speckling) General Information: - immobile within plant - ionic forms: Mn +2

Copper Functions: - needed for chlorophyll production - assists in activating various enzyme systems deficiency symptom (leaf tip die back) General Information: - immobile within plant - ionic forms: Cu +2

Molybdenum Functions: - needed for nitrogen metabolism - needed by legume crops for N fixation deficiency symptoms (chlorosis with marginal necrosis) General Information: - mobile within plant - ionic forms: MoO 4 -2

Boron Functions: - needed for integrity of cell walls and membranes - needed to insure good pollination deficiency symptom (abnormal apical development) General Information: - immobile within plant - ionic form: H 3 BO 3

Chlorine Functions: - involved in photosynthesis - helps regulate stomatal opening/closing toxicity symptoms (chlorosis with tip and marginal burn) General Information: - mobile within plant - ionic forms: Cl -