Plant Fertility

Terms and Definitions Essential Nutrient Deficiency Plant dies without it Inadequate amounts = plant shows deficiency Required for yield Required to complete lifecycle Deficiency Plant condition where an essential nutrient is not adequately supplied

Terms and Definitions Symptom Fertilizer A visual sign or condition that results from a deficiency: aids in diagnosing a deficiency. Fertilizer Natural, manufactured, or processed materials that contain one or more of the essential nutrients; available in: dry, liquid, and gaseous form

Essential Nutrients (18) Non-mineral – from air and water Carbon (C) Hydrogen (H) Oxygen (O) Primary Macronutrients Nitrogen (N) Phosphorus (P) Potassium (K)…aka “Potash”

Essential Nutrients Secondary Macronutrients Micronutrients Calcium (Ca) Magnesium (Mg) Sulfur (S) Micronutrients Iron (Fe) – Zinc (Zn) Nickel (Ni) – Copper (Cu) Manganese (Mn) – Boron (B) Chlorine (Cl) – Cobalt (Co) Molybdenum (Mo)

“The Big 10” Essential Elements Carbon (C) Hydrogen (H) Oxygen (O) Phosphorus (P) Potash (K) Nitrogen (N) Sulfur (S) Calcium (Ca) Iron (Fe) Magnesium (Mg) C. HOPKINS CAFÉ Mighty Good

Plant Nutrient Availability ** Most nutrients cannot be taken up by plants as the “stable” element. Plant nutrients are available as ions: Cation Positive-charged ion Anion Negative-charged ion

Plant Nutrient Availability Primary nutrient forms: Nitrogen Ammonia (NH4+) Nitrate (NO3-) Phosphorus—hydrogen phosphates H2PO3- & HPO32- Potassium K+

Plant Nutrient Availability Other nutrient forms: Calcium (Ca2+) Magnesium (Mg2+) Sulfur—Sulfate (SO42-) Iron, Copper, Zinc, Manganese & Nickel (Xx2+) Chlorine—Chloride (Cl-) Boron—Borate (BO33-) Molybdenum—Molybdenate (MoO42-)

Primary Nutrient Functions Nitrogen Functions Occurs mainly in protein Component of chlorophyll (green color) Promotes vegetative growth Nitrogen Deficiencies Mobile nutrient Deficiencies occur in older leaves first Chlorosis and stunted growth

Primary Nutrient Functions Phosphorus Functions Major component of chromosomes (DNA & RNA) Energy transfer and storage—promotes root development Promotes maturity—fruit and seed formation Phosphorus Deficiencies Stunted growth Leaves darken and turn reddish purple (grasses) or bluish (legumes) Discoloration occurs in younger leaves

Primary Nutrient Functions Potassium Functions Synthesis of protein, carbohydrates and chlorophyll Regulates nutrient and H2O absorption by plant roots Promotes seed (grain) development and size Potassium Deficiencies Occurs in older leaves Chlorosis or speckled leaves Weak stems/lodging

Soil pH What is pH? Measures the concentration of H+ ions in a substance Concentrations measured by a factor of 10 (ex: pH of 1 is 10 times stronger than 2, etc.) Range 0-14 Neutral pH = 7 <7 = acidic >7 = alkaline or basic Iowa soil pH: 6 – 7.5

Soil pH pH affects nutrient availability

Soil pH Different crops prefer different pH levels:

Changing Soil pH Lowering pH (increasing acidity) Adding sulfur compounds Adding nitrogen fertilizer Good soil drainage High rainfall Parent material high in acid elements

Changing Soil pH Raising pH (increasing alkalinity) Adding lime (CaCO3) Poor drainage Low rainfall Parent material high in alkaline base elements